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Coroutines and RxJava - An Asynchronicity Comparison

M
Manuel Vicente Vivo

The document provides an overview and comparison of coroutines and RxJava for asynchronous programming in Kotlin. It begins with a recap of coroutines concepts. Then it compares key topics between the two libraries like cancellation, channels, and concurrency. The goal is to help attendees learn the differences and similarities between coroutines and RxJava and use what they learned to build an example app.

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C O R O U T I N E S A N D R X J AVA A N A S Y N C H R O N I C I T Y C O M PA R I S O N M A N U E L V I C E N T E V I V O @ M A N U E LV I C N T
@manuelvicnt #DroidconBos A G E N D A • Coroutines Recap • RxJava & Coroutines concepts • Build an App
@manuelvicnt #DroidconBos G O A L S • Learn Coroutines with basic RxJava knowledge • Compare both libraries on different topics • Use what we learned to build the App • Code available
@manuelvicnt #DroidconBos T H E A P P
@manuelvicnt #DroidconBos I N T E N D E D A U D I E N C E • Able to read Kotlin code • Basic RxJava experience • Coroutines 101 • You want to learn differences and similarities between RxJava and Coroutines
@manuelvicnt #DroidconBos I H E A R D C O R O U T I N E S ? • From the Kotlin documentation… • Coroutines simplify asynchronous programming • Code can be expressed sequentially and the library handles the asynchronous code for us • Computations can be suspended without blocking a Thread
@manuelvicnt #DroidconBos I H E A R D C O R O U T I N E S ? • From the Kotlin documentation… • Coroutines simplify asynchronous programming • Code can be expressed sequentially and the library handles the asynchronous code for us • Computations can be suspended without blocking a Thread
@manuelvicnt #DroidconBos I H E A R D C O R O U T I N E S ? • From the Kotlin documentation… • Coroutines simplify asynchronous programming • Code can be expressed sequentially and the library handles the asynchronous code for us • Computations can be suspended without blocking a Thread
I WA N T T O P L AY A G A M E
@manuelvicnt #DroidconBos What is this? launch(CommonPool) { heavyComputation() }
@manuelvicnt #DroidconBos What is this? launch(CommonPool) { heavyComputation() } Coroutine
@manuelvicnt #DroidconBos What is this? launch(CommonPool) { heavyComputation() }
@manuelvicnt #DroidconBos What is this? launch(CommonPool) { heavyComputation() } Coroutine Builder
@manuelvicnt #DroidconBos What is this? launch(CommonPool) { heavyComputation() }
@manuelvicnt #DroidconBos What is this? launch(CommonPool) { heavyComputation() } Coroutine Context
@manuelvicnt #DroidconBos What is this? launch(CommonPool) { heavyComputation() }
@manuelvicnt #DroidconBos What is this? launch(CommonPool) { heavyComputation() } Suspending Lambda
@manuelvicnt #DroidconBos What is this? launch(CommonPool) { heavyComputation() val data = makeNetworkRequest() updateDB(data) } Suspending Lambda
@manuelvicnt #DroidconBos What is this? launch(CommonPool) { heavyComputation() val data = makeNetworkRequest() updateDB(data) } Suspending Lambda
@manuelvicnt #DroidconBos What is this? launch(CommonPool) { heavyComputation() val data = makeNetworkRequest() updateDB(data) } Suspending Lambda
@manuelvicnt #DroidconBos What is this? launch(CommonPool) { heavyComputation() val data = makeNetworkRequest() updateDB(data) } Suspending Lambda
@manuelvicnt #DroidconBos What is this? launch(CommonPool) { heavyComputation() val data = makeNetworkRequest() updateDB(data) } Suspending Lambda
@manuelvicnt #DroidconBos What is this? launch(CommonPool) { heavyComputation() val data = makeNetworkRequest() updateDB(data) } Suspending Lambda
@manuelvicnt #DroidconBos What is this? launch(CommonPool) { heavyComputation() val data = makeNetworkRequest() updateDB(data) } Suspending Lambda
@manuelvicnt #DroidconBos What is this? launch(CommonPool) { heavyComputation() val data = makeNetworkRequest() updateDB(data) } Suspending Lambda
C O R O U T I N E S R E C A P C O M P L E T E D
C O R O U T I N E S - R X J AVA C O M PA R I S O N
C A N C E L E X E C U T I O N
@manuelvicnt #DroidconBos With Disposables How to cancel an Observable?
@manuelvicnt #DroidconBos With Disposables How to cancel an Observable? val disposable: Disposable = Observable.interval(1, TimeUnit.SECONDS) .subscribe() disposable.dispose()
@manuelvicnt #DroidconBos With Disposables How to cancel an Observable? val disposable: Disposable = Observable.interval(1, TimeUnit.SECONDS) .subscribe() disposable.dispose()
@manuelvicnt #DroidconBos With the Coroutine Job (from the Coroutine Context) How to cancel a Coroutine?
@manuelvicnt #DroidconBos With the Coroutine Job (from the Coroutine Context) How to cancel a Coroutine? val job = launch(CommonPool) { // my suspending block } job.cancel()
@manuelvicnt #DroidconBos With the Coroutine Job (from the Coroutine Context) How to cancel a Coroutine? val parentJob = Job() launch(parentJob + CommonPool) { // my suspending block } parentJob.cancel()
@manuelvicnt #DroidconBos With the Coroutine Job (from the Coroutine Context) How to cancel a Coroutine? val parentJob = Job() launch(CommonPool, parent = parentJob) { // my suspending block } parentJob.cancel()
C H A N N E L S
@manuelvicnt #DroidconBos C H A N N E L S • Transfer stream of values • Similar to Reactive Streams Publisher or RxJava Observable/Flowable
@manuelvicnt #DroidconBos C H A N N E L S • Transfer stream of values • Similar to Reactive Streams Publisher or RxJava Observable/Flowable Observable.create<Int> { emitter -> for (i in 1..5) { emitter.onNext(i) } emitter.onComplete() }
@manuelvicnt #DroidconBos Observable.create<Int> { emitter -> for (i in 1..5) { emitter.onNext(i) } emitter.onComplete() } C H A N N E L S
@manuelvicnt #DroidconBos Observable.create<Int> { emitter -> for (i in 1..5) { emitter.onNext(i) } emitter.onComplete() } C H A N N E L S
@manuelvicnt #DroidconBos Observable.create<Int> { emitter -> for (i in 1..5) { emitter.onNext(i) } emitter.onComplete() } C H A N N E L S
@manuelvicnt #DroidconBos Observable.create<Int> { emitter -> for (i in 1..5) { emitter.onNext(i) } emitter.onComplete() }.subscribe() C H A N N E L S
@manuelvicnt #DroidconBos C H A N N E L S Observable.create<Int> { emitter -> for (i in 1..5) { emitter.onNext(i) } emitter.onComplete() }.subscribe()
@manuelvicnt #DroidconBos C H A N N E L S Observer Timeline Observable.create<Int> { emitter -> for (i in 1..5) { emitter.onNext(i) } emitter.onComplete() }.subscribe()
@manuelvicnt #DroidconBos C H A N N E L S Observer Timeline 1 Observable.create<Int> { emitter -> for (i in 1..5) { emitter.onNext(i) } emitter.onComplete() }.subscribe()
@manuelvicnt #DroidconBos C H A N N E L S Observer Timeline 1 2 Observable.create<Int> { emitter -> for (i in 1..5) { emitter.onNext(i) } emitter.onComplete() }.subscribe()
@manuelvicnt #DroidconBos C H A N N E L S Observer Timeline 1 2 3 Observable.create<Int> { emitter -> for (i in 1..5) { emitter.onNext(i) } emitter.onComplete() }.subscribe()
@manuelvicnt #DroidconBos C H A N N E L S Observer Timeline 1 2 3 4 Observable.create<Int> { emitter -> for (i in 1..5) { emitter.onNext(i) } emitter.onComplete() }.subscribe()
@manuelvicnt #DroidconBos C H A N N E L S Observer Timeline 1 2 3 4 5 Observable.create<Int> { emitter -> for (i in 1..5) { emitter.onNext(i) } emitter.onComplete() }.subscribe()
@manuelvicnt #DroidconBos C H A N N E L S Observer Timeline 1 2 3 4 5 Observable.create<Int> { emitter -> for (i in 1..5) { emitter.onNext(i) } emitter.onComplete() }.subscribe()
@manuelvicnt #DroidconBos C H A N N E L S Observer Timeline 1 2 3 4 5 Observable.create<Int> { emitter -> for (i in 1..5) { emitter.onNext(i) } emitter.onComplete() }.subscribe()
@manuelvicnt #DroidconBos C H A N N E L S Observer Timeline 1 2 3 4 5 Observer 2 Timeline Observable.create<Int> { emitter -> for (i in 1..5) { emitter.onNext(i) } emitter.onComplete() }.subscribe()
@manuelvicnt #DroidconBos C H A N N E L S Observer Timeline 1 2 3 4 5 Observer 2 Timeline 1 Observable.create<Int> { emitter -> for (i in 1..5) { emitter.onNext(i) } emitter.onComplete() }.subscribe()
@manuelvicnt #DroidconBos C H A N N E L S Observer Timeline 1 2 3 4 5 Observer 2 Timeline 1 2 Observable.create<Int> { emitter -> for (i in 1..5) { emitter.onNext(i) } emitter.onComplete() }.subscribe()
@manuelvicnt #DroidconBos C H A N N E L S Observer Timeline 1 2 3 4 5 Observer 2 Timeline 1 2 3 Observable.create<Int> { emitter -> for (i in 1..5) { emitter.onNext(i) } emitter.onComplete() }.subscribe()
@manuelvicnt #DroidconBos C H A N N E L S Observer Timeline 1 2 3 4 5 Observer 2 Timeline 1 2 3 4 Observable.create<Int> { emitter -> for (i in 1..5) { emitter.onNext(i) } emitter.onComplete() }.subscribe()
@manuelvicnt #DroidconBos C H A N N E L S Observer Timeline 1 2 3 4 5 Observer 2 Timeline 1 2 3 4 5 Observable.create<Int> { emitter -> for (i in 1..5) { emitter.onNext(i) } emitter.onComplete() }.subscribe()
@manuelvicnt #DroidconBos C H A N N E L S Observer Timeline 1 2 3 4 5 Observer 2 Timeline 1 2 3 4 5 Observable.create<Int> { emitter -> for (i in 1..5) { emitter.onNext(i) } emitter.onComplete() }.subscribe()
@manuelvicnt #DroidconBos C H A N N E L S • Transfer stream of values • Can be shared between different Coroutines • By default, channel capacity == 1
@manuelvicnt #DroidconBos C H A N N E L S • Transfer stream of values • Can be shared between different Coroutines • By default, channel capacity == 1 interface Channel<E> : SendChannel<E>, ReceiveChannel<E>
@manuelvicnt #DroidconBos interface Channel<E> : SendChannel<E>, ReceiveChannel<E> C H A N N E L S
@manuelvicnt #DroidconBos interface Channel<E> : SendChannel<E>, ReceiveChannel<E> public interface SendChannel<in E> { public suspend fun send(element: E) public fun offer(element: E) public fun close(cause: Throwable? = null): Boolean } public interface ReceiveChannel<out E> { public suspend fun receive(): E public fun close(cause: Throwable? = null): Boolean } C H A N N E L S
@manuelvicnt #DroidconBos interface Channel<E> : SendChannel<E>, ReceiveChannel<E> public interface SendChannel<in E> { public suspend fun send(element: E) public fun offer(element: E) public fun close(cause: Throwable? = null): Boolean } public interface ReceiveChannel<out E> { public suspend fun receive(): E public fun close(cause: Throwable? = null): Boolean } C H A N N E L S
@manuelvicnt #DroidconBos interface Channel<E> : SendChannel<E>, ReceiveChannel<E> public interface SendChannel<in E> { public suspend fun send(element: E) public fun offer(element: E) public fun close(cause: Throwable? = null): Boolean } public interface ReceiveChannel<out E> { public suspend fun receive(): E public fun close(cause: Throwable? = null): Boolean } C H A N N E L S
@manuelvicnt #DroidconBos interface Channel<E> : SendChannel<E>, ReceiveChannel<E> public interface SendChannel<in E> { public suspend fun send(element: E) public fun offer(element: E) public fun close(cause: Throwable? = null): Boolean } public interface ReceiveChannel<out E> { public suspend fun receive(): E public fun close(cause: Throwable? = null): Boolean } C H A N N E L S
@manuelvicnt #DroidconBos C H A N N E L S val channel = Channel<Int>() Channel
@manuelvicnt #DroidconBos C H A N N E L S val channel = Channel<Int>() Channel launch { channel.send(1) }
@manuelvicnt #DroidconBos C H A N N E L S val channel = Channel<Int>() Channel 1 launch { channel.send(1) }
@manuelvicnt #DroidconBos C H A N N E L S val channel = Channel<Int>() Channel 1 launch { channel.send(1) } launch { val value = channel.receive() }
@manuelvicnt #DroidconBos C H A N N E L S val channel = Channel<Int>() Channel 1 launch { channel.send(1) } launch { val value = channel.receive() }
@manuelvicnt #DroidconBos C H A N N E L S val channel = Channel<Int>() Channel CapacityChannel 1
@manuelvicnt #DroidconBos C H A N N E L S val channel = Channel<Int>() Channel Capacity launch { channel.send(1) channel.send(2) } Channel 1
@manuelvicnt #DroidconBos C H A N N E L S val channel = Channel<Int>() Channel Capacity launch { channel.send(1) channel.send(2) } Channel 1
@manuelvicnt #DroidconBos C H A N N E L S val channel = Channel<Int>() Channel Capacity 1 launch { channel.send(1) channel.send(2) } Channel 0
@manuelvicnt #DroidconBos C H A N N E L S val channel = Channel<Int>() Channel Capacity 1 launch { channel.send(1) channel.send(2) } Channel 0
@manuelvicnt #DroidconBos C H A N N E L S val channel = Channel<Int>() Channel Capacity 1 launch { channel.send(1) channel.send(2) } Channel 0 // Suspended until the // channel is NOT full
@manuelvicnt #DroidconBos C H A N N E L S val channel = Channel<Int>() Channel Capacity 1 launch { channel.send(1) channel.send(2) } Channel 0 // Suspended until the // channel is NOT full launch { val value = channel.receive() }
@manuelvicnt #DroidconBos C H A N N E L S val channel = Channel<Int>() Channel Capacity launch { channel.send(1) channel.send(2) } Channel 1 // Suspended until the // channel is NOT full launch { val value = channel.receive() } 1
@manuelvicnt #DroidconBos C H A N N E L S val channel = Channel<Int>() Channel Capacity launch { channel.send(1) channel.send(2) } Channel 1 // Suspended until the // channel is NOT full launch { val value = channel.receive() } 1
@manuelvicnt #DroidconBos C H A N N E L S val channel = Channel<Int>() Channel Capacity launch { channel.send(1) channel.send(2) } Channel launch { val value = channel.receive() } 11
@manuelvicnt #DroidconBos C H A N N E L S val channel = Channel<Int>() Channel Capacity launch { channel.send(1) channel.send(2) } Channel launch { val value = channel.receive() } 11
@manuelvicnt #DroidconBos C H A N N E L S val channel = Channel<Int>() Channel Capacity launch { channel.send(1) channel.send(2) } Channel 0 launch { val value = channel.receive() } 21
@manuelvicnt #DroidconBos C H A N N E L S val channel = Channel<Int>() launch { for (x in 1..5) channel.send(x) }
@manuelvicnt #DroidconBos C H A N N E L S val channel = Channel<Int>() launch { for (x in 1..5) channel.send(x) } launch { for (value in channel) { consumeValue(value) } } Channel
@manuelvicnt #DroidconBos C H A N N E L S val channel = Channel<Int>() launch { for (x in 1..5) channel.send(x) } launch { for (value in channel) { consumeValue(value) } } Channel 1
@manuelvicnt #DroidconBos C H A N N E L S val channel = Channel<Int>() launch { for (x in 1..5) channel.send(x) } launch { for (value in channel) { consumeValue(value) } } Channel 1 2
@manuelvicnt #DroidconBos C H A N N E L S val channel = Channel<Int>() launch { for (x in 1..5) channel.send(x) } launch { for (value in channel) { consumeValue(value) } } Channel 1 2 3
@manuelvicnt #DroidconBos C H A N N E L S val channel = Channel<Int>() launch { for (x in 1..5) channel.send(x) } launch { for (value in channel) { consumeValue(value) } } Channel 1 2 3 4
@manuelvicnt #DroidconBos C H A N N E L S val channel = Channel<Int>() launch { for (x in 1..5) channel.send(x) } launch { for (value in channel) { consumeValue(value) } } Channel 1 2 3 4 5
@manuelvicnt #DroidconBos C H A N N E L S val channel = Channel<Int>() launch { for (x in 1..5) channel.send(x) } launch { for (value in channel) { consumeValue(value) } } Channel 1 2 3 4 5
@manuelvicnt #DroidconBos C H A N N E L S Channel 1 2 3 4 5 launch { consumeValue(channel.receive()) }
@manuelvicnt #DroidconBos C H A N N E L S Channel 1 2 3 4 5 launch { consumeValue(channel.receive()) }
@manuelvicnt #DroidconBos C H A N N E L S Channel 1 2 3 4 5 launch { consumeValue(channel.receive()) }
@manuelvicnt #DroidconBos C H A N N E L S Channel 1 2 3 4 5 launch { consumeValue(channel.receive()) } // Suspended until the // channel is NOT empty
@manuelvicnt #DroidconBos B U F F E R E D C H A N N E L S • Channels take an optional capacity parameter • Allow senders to send multiple elements before suspending
@manuelvicnt #DroidconBos B U F F E R E D C H A N N E L S • Channels take an optional capacity parameter • Allow senders to send multiple elements before suspending val channel = Channel<Int>(3)
@manuelvicnt #DroidconBos C H A N N E L S • We can also use produce that implements the ReceiveChannel interface • Only the code inside produce can send elements to the channel • Useful to create custom operators
@manuelvicnt #DroidconBos C H A N N E L S • We can also use produce that implements the ReceiveChannel interface • Only the code inside produce can send elements to the channel • Useful to create custom operators val publisher = produce(capacity = 2) { for (x in 1..5) send(x) }
@manuelvicnt #DroidconBos C H A N N E L S val publisher = produce(capacity = 2) { for (x in 1..5) send(x) }
@manuelvicnt #DroidconBos C H A N N E L S val publisher = produce(capacity = 2) { for (x in 1..5) send(x) } launch { publisher.consumeEach { consumeValue(it) } }
@manuelvicnt #DroidconBos R A C E C O N D I T I O N I N C H A N N E L S val channel = Channel<Int>()
@manuelvicnt #DroidconBos R A C E C O N D I T I O N I N C H A N N E L S launch { val value1 = channel.receive() } launch { val value2 = channel.receive() } val channel = Channel<Int>()
@manuelvicnt #DroidconBos R A C E C O N D I T I O N I N C H A N N E L S launch { val value1 = channel.receive() } launch { val value2 = channel.receive() } val channel = Channel<Int>() launch { channel.send(1) }
B R O A D C A S T C H A N N E L
@manuelvicnt #DroidconBos B R O A D C A S T C H A N N E L • Similar to RxJava Subjects • Rx Hot Observable behavior
@manuelvicnt #DroidconBos B R O A D C A S T C H A N N E L • Similar to RxJava Subjects • Rx Hot Observable behavior publishSubject.subscribe { consumeValue(it) } publishSubject.subscribe { println(it) } Observer 1 Timeline Observer 2 Timeline
@manuelvicnt #DroidconBos B R O A D C A S T C H A N N E L • Similar to RxJava Subjects • Rx Hot Observable behavior publishSubject.subscribe { consumeValue(it) } publishSubject.subscribe { println(it) } publishSubject.onNext(3) Observer 1 Timeline Observer 2 Timeline
@manuelvicnt #DroidconBos B R O A D C A S T C H A N N E L • Similar to RxJava Subjects • Rx Hot Observable behavior publishSubject.subscribe { consumeValue(it) } publishSubject.subscribe { println(it) } publishSubject.onNext(3) Observer 1 Timeline Observer 2 Timeline 3 3
@manuelvicnt #DroidconBos B R O A D C A S T C H A N N E L • BroadcastChannel implements the SendChannel<E> interface • Emit the same item to multiple consumers that listen for the elements using openSubscription() val channel = BroadcastChannel<Int>(2)
@manuelvicnt #DroidconBos B R O A D C A S T C H A N N E L val channel = BroadcastChannel<Int>(2) val observer1Job = launch { channel.openSubscription().use { channel -> for (value in channel) { consumeValue(value) } } }
@manuelvicnt #DroidconBos B R O A D C A S T C H A N N E L Observer 1 Timeline val channel = BroadcastChannel<Int>(2) val observer1Job = launch { channel.openSubscription().use { channel -> for (value in channel) { consumeValue(value) } } }
@manuelvicnt #DroidconBos B R O A D C A S T C H A N N E L val observer2Job = launch { channel.consumeEach { value -> consumeValue(value) } }
@manuelvicnt #DroidconBos B R O A D C A S T C H A N N E L val observer2Job = launch { channel.consumeEach { value -> consumeValue(value) } } Observer 2 Timeline
@manuelvicnt #DroidconBos B R O A D C A S T C H A N N E L Observer 2 Timeline Observer 1 Timeline Channel Capacity 2
@manuelvicnt #DroidconBos B R O A D C A S T C H A N N E L Observer 2 Timeline Observer 1 Timeline Channel Capacity 2
@manuelvicnt #DroidconBos B R O A D C A S T C H A N N E L Observer 2 Timeline Observer 1 Timeline channel.send(4) Channel Capacity 1
@manuelvicnt #DroidconBos B R O A D C A S T C H A N N E L Observer 2 Timeline Observer 1 Timeline channel.send(4) 4 Channel Capacity 1
@manuelvicnt #DroidconBos B R O A D C A S T C H A N N E L Observer 2 Timeline Observer 1 Timeline channel.send(4) 4 Channel Capacity 1
@manuelvicnt #DroidconBos B R O A D C A S T C H A N N E L Observer 2 Timeline Observer 1 Timeline channel.send(4) 4 4 Channel Capacity 2
@manuelvicnt #DroidconBos B R O A D C A S T C H A N N E L Observer 2 Timeline Observer 1 Timeline channel.send(4) 4 4 Channel Capacity 2
@manuelvicnt #DroidconBos B R O A D C A S T C H A N N E L Observer 2 Timeline Observer 1 Timeline channel.send(4) 4 4 channel.send(2) Channel Capacity 1
@manuelvicnt #DroidconBos B R O A D C A S T C H A N N E L Observer 2 Timeline Observer 1 Timeline channel.send(4) 4 4 channel.send(2) 2 Channel Capacity 1
@manuelvicnt #DroidconBos B R O A D C A S T C H A N N E L Observer 2 Timeline Observer 1 Timeline channel.send(4) 4 4 channel.send(2) 2 Channel Capacity 1
@manuelvicnt #DroidconBos B R O A D C A S T C H A N N E L Observer 2 Timeline Observer 1 Timeline channel.send(4) 4 4 channel.send(2) 2 2 Channel Capacity 2
@manuelvicnt #DroidconBos B R O A D C A S T C H A N N E L • Special mention to ConflatedBroadcastChannel • Conflated is a special type of capacity • Behavior similar to Rx BehaviorSubject
@manuelvicnt #DroidconBos C O N F L AT E D B R O A D C A S T C H A N N E L Observer 1 Timeline 4 2
@manuelvicnt #DroidconBos C O N F L AT E D B R O A D C A S T C H A N N E L Observer 1 Timeline 4 2 // Closes Subscription
@manuelvicnt #DroidconBos C O N F L AT E D B R O A D C A S T C H A N N E L Observer 1 Timeline 4 2 // Closes Subscription // Resubscribes to ConflatedBroadcastChannel
@manuelvicnt #DroidconBos C O N F L AT E D B R O A D C A S T C H A N N E L Observer 1 Timeline 4 2 // Closes Subscription // Resubscribes to ConflatedBroadcastChannel New Observer 1 Timeline 2
@manuelvicnt #DroidconBos It’s supported by default What about Rx back-pressure?
@manuelvicnt #DroidconBos Observable Channel Subject Broadcast Channel Cold Hot Hot Hot Unicast Unicast Broadcast Broadcast C O M PA R I S O N
@manuelvicnt #DroidconBos C H A N N E L S • If we want a “Cold Observable” behavior, we can use publish
@manuelvicnt #DroidconBos C H A N N E L S • If we want a “Cold Observable” behavior, we can use publish val publisher = publish { for (x in 1..5) send(x) }
@manuelvicnt #DroidconBos C H A N N E L S • If we want a “Cold Observable” behavior, we can use publish val publisher = publish { for (x in 1..5) send(x) } publisher.openSubscription().use { channel -> for (value in channel) { consumeValue(value) } }
I N T E R O P org.jetbrains.kotlinx:kotlinx-coroutines-rx2:$kotlin_coroutines_version
@manuelvicnt #DroidconBos R X J AVA - > C O R O U T I N E S • OpenSubscription Observable.interval( 1, TimeUnit.SECONDS ) .openSubscription().use { channel -> for (value in channel) { consumeValue(value) } }
@manuelvicnt #DroidconBos R X J AVA - > C O R O U T I N E S • OpenSubscription Observable.interval( 1, TimeUnit.SECONDS ) .openSubscription().use { channel -> for (value in channel) { consumeValue(value) } }
@manuelvicnt #DroidconBos R X J AVA - > C O R O U T I N E S • OpenSubscription Observable.interval( 1, TimeUnit.SECONDS ) .openSubscription().use { channel -> for (value in channel) { consumeValue(value) } }
@manuelvicnt #DroidconBos R X J AVA - > C O R O U T I N E S • Await
@manuelvicnt #DroidconBos R X J AVA - > C O R O U T I N E S • Await val value = Observable.interval( 1, TimeUnit.SECONDS ) .awaitFirstOrDefault(-1)
@manuelvicnt #DroidconBos R X J AVA - > C O R O U T I N E S • Await val value = Observable.interval( 1, TimeUnit.SECONDS ) .awaitFirstOrDefault(-1)
@manuelvicnt #DroidconBos C O R O U T I N E S - > R X J AVA • Job.asCompletable
@manuelvicnt #DroidconBos C O R O U T I N E S - > R X J AVA • Job.asCompletable val job = launch { heavyComputation() } job.asCompletable(CommonPool).subscribe({ // Job completed })
@manuelvicnt #DroidconBos C O R O U T I N E S - > R X J AVA • Job.asCompletable val job = launch { heavyComputation() } job.asCompletable(CommonPool).subscribe({ // Job completed })
@manuelvicnt #DroidconBos C O R O U T I N E S - > R X J AVA • Job.asCompletable val job = launch { heavyComputation() } job.asCompletable(CommonPool).subscribe({ // Job completed })
@manuelvicnt #DroidconBos C O R O U T I N E S - > R X J AVA • Deferred.asSingle val deferred = async { heavyComputation() } deferred.asSingle(CommonPool).subscribe({ // Job completed }, { // Error happened })
@manuelvicnt #DroidconBos C O R O U T I N E S - > R X J AVA • Deferred.asSingle val deferred = async { heavyComputation() } deferred.asSingle(CommonPool).subscribe({ // Job completed }, { // Error happened })
@manuelvicnt #DroidconBos C O R O U T I N E S - > R X J AVA • Deferred.asSingle val deferred = async { heavyComputation() } deferred.asSingle(CommonPool).subscribe({ // Job completed }, { // Error happened })
@manuelvicnt #DroidconBos C O R O U T I N E S - > R X J AVA • CoroutineBuilders • rxCompletable • rxMaybe • rxSingle • rxObservable • rxFlowable
@manuelvicnt #DroidconBos C O R O U T I N E S - > R X J AVA • CoroutineBuilders • rxCompletable • rxMaybe • rxSingle • rxObservable • rxFlowable rxCompletable { // Suspending lambda }.subscribe()
A C T O R S
@manuelvicnt #DroidconBos A C T O R S • Actor = Coroutine + Channel • Opposite of produce
@manuelvicnt #DroidconBos A C T O R S • Actor = Coroutine + Channel • Opposite of produce val actor = actor<Int>() { for (int in channel) { // iterate over received Integers } }
@manuelvicnt #DroidconBos A C T O R S • Actor = Coroutine + Channel • Opposite of produce val actor = actor<Int>() { for (int in channel) { // iterate over received Integers } } launch { actor.send(2) }
@manuelvicnt #DroidconBos A C T O R S val userActionActor = actor<MainUserAction>(CommonPool) { for (msg in channel) { // iterate over incoming messages when (msg) { is MainUserAction.FirstAction -> { // Do something } is MainUserAction.SecondAction -> { // Do something } } } }
@manuelvicnt #DroidconBos A C T O R S val userActionActor = actor<MainUserAction>(CommonPool) { for (msg in channel) { // iterate over incoming messages when (msg) { is MainUserAction.FirstAction -> { // Do something } is MainUserAction.SecondAction -> { // Do something } } } }
@manuelvicnt #DroidconBos A C T O R S val userActionActor = actor<MainUserAction>(CommonPool) { for (msg in channel) { // iterate over incoming messages when (msg) { is MainUserAction.FirstAction -> { // Do something } is MainUserAction.SecondAction -> { // Do something } } } }
@manuelvicnt #DroidconBos A C T O R S val userActionActor = actor<MainUserAction>(CommonPool) { for (msg in channel) { when (msg) { is MainUserAction.FirstAction -> { // Do something } is MainUserAction.SecondAction -> { // Do something } } } }
O P E R AT O R S
@manuelvicnt #DroidconBos O P E R AT O R S • Some operators are built into the language with Kotlin Collections RxJava Coroutines map map filter filter skip drop reduce reduce
@manuelvicnt #DroidconBos O P E R AT O R S • Some others are easy to implement fun range( context: CoroutineContext, start: Int, count: Int ) = publish(context) { for (x in start until start + count) send(x) }
@manuelvicnt #DroidconBos O P E R AT O R S • Some others require more work • Completable.zip suspend fun zip(block: () -> Unit, block2: () -> Unit) { val deferred1 = async { block() } val deferred2 = async { block2() } deferred1.await() deferred2.await() }
@manuelvicnt #DroidconBos C O M P L E X O P E R AT O R S RxJava Coroutines timeout withTimeoutOrNull retry repeat(times) debounce ReceiveChannel<T>.debounce() groupBy groupBy
T H R E A D I N G
@manuelvicnt #DroidconBos T H R E A D I N G I N R X
@manuelvicnt #DroidconBos T H R E A D I N G I N R X • Threading control Operators: observeOn and subscribeOn
@manuelvicnt #DroidconBos T H R E A D I N G I N R X • Threading control Operators: observeOn and subscribeOn • Scheduler is a tool that schedules actions to be performed
@manuelvicnt #DroidconBos T H R E A D I N G I N R X • Threading control Operators: observeOn and subscribeOn • Scheduler is a tool that schedules actions to be performed • You can create your own Scheduler
@manuelvicnt #DroidconBos T H R E A D I N G Single.zip( Single.just(3), Single.just(4), BiFunction<Int, Int, Int> { n1, n2 -> n1 + n2 } ) .subscribeOn(Schedulers.computation()) .observeOn(Schedulers.io()) .flatMap { n -> Single.just(n * n) } .observeOn(Schedulers.computation()) .flatMap { n -> Single.just(n - 1) } .observeOn(AndroidSchedulers.mainThread()) .subscribe({ println("Finished with result $it") }, { println("Failed with error $it") })
@manuelvicnt #DroidconBos T H R E A D I N G Single.zip( Single.just(3), Single.just(4), BiFunction<Int, Int, Int> { n1, n2 -> n1 + n2 } ) .subscribeOn(Schedulers.computation()) .observeOn(Schedulers.io()) .flatMap { n -> Single.just(n * n) } .observeOn(Schedulers.computation()) .flatMap { n -> Single.just(n - 1) } .observeOn(AndroidSchedulers.mainThread()) .subscribe({ println("Finished with result $it") }, { println("Failed with error $it") })
@manuelvicnt #DroidconBos T H R E A D I N G Single.zip( Single.just(3), Single.just(4), BiFunction<Int, Int, Int> { n1, n2 -> n1 + n2 } ) .subscribeOn(Schedulers.computation()) .observeOn(Schedulers.io()) .flatMap { n -> Single.just(n * n) } .observeOn(Schedulers.computation()) .flatMap { n -> Single.just(n - 1) } .observeOn(AndroidSchedulers.mainThread()) .subscribe({ println("Finished with result $it") }, { println("Failed with error $it") })
@manuelvicnt #DroidconBos T H R E A D I N G Single.zip( Single.just(3), Single.just(4), BiFunction<Int, Int, Int> { n1, n2 -> n1 + n2 } ) .subscribeOn(Schedulers.computation()) .observeOn(Schedulers.io()) .flatMap { n -> Single.just(n * n) } .observeOn(Schedulers.computation()) .flatMap { n -> Single.just(n - 1) } .observeOn(AndroidSchedulers.mainThread()) .subscribe({ println("Finished with result $it") }, { println("Failed with error $it") }) Computation
@manuelvicnt #DroidconBos T H R E A D I N G Single.zip( Single.just(3), Single.just(4), BiFunction<Int, Int, Int> { n1, n2 -> n1 + n2 } ) .subscribeOn(Schedulers.computation()) .observeOn(Schedulers.io()) .flatMap { n -> Single.just(n * n) } .observeOn(Schedulers.computation()) .flatMap { n -> Single.just(n - 1) } .observeOn(AndroidSchedulers.mainThread()) .subscribe({ println("Finished with result $it") }, { println("Failed with error $it") })
@manuelvicnt #DroidconBos T H R E A D I N G Single.zip( Single.just(3), Single.just(4), BiFunction<Int, Int, Int> { n1, n2 -> n1 + n2 } ) .subscribeOn(Schedulers.computation()) .observeOn(Schedulers.io()) .flatMap { n -> Single.just(n * n) } .observeOn(Schedulers.computation()) .flatMap { n -> Single.just(n - 1) } .observeOn(AndroidSchedulers.mainThread()) .subscribe({ println("Finished with result $it") }, { println("Failed with error $it") }) Computation
@manuelvicnt #DroidconBos T H R E A D I N G Single.zip( Single.just(3), Single.just(4), BiFunction<Int, Int, Int> { n1, n2 -> n1 + n2 } ) .subscribeOn(Schedulers.computation()) .observeOn(Schedulers.io()) .flatMap { n -> Single.just(n * n) } .observeOn(Schedulers.computation()) .flatMap { n -> Single.just(n - 1) } .observeOn(AndroidSchedulers.mainThread()) .subscribe({ println("Finished with result $it") }, { println("Failed with error $it") }) Computation
@manuelvicnt #DroidconBos T H R E A D I N G Single.zip( Single.just(3), Single.just(4), BiFunction<Int, Int, Int> { n1, n2 -> n1 + n2 } ) .subscribeOn(Schedulers.computation()) .observeOn(Schedulers.io()) .flatMap { n -> Single.just(n * n) } .observeOn(Schedulers.computation()) .flatMap { n -> Single.just(n - 1) } .observeOn(AndroidSchedulers.mainThread()) .subscribe({ println("Finished with result $it") }, { println("Failed with error $it") }) Computation Io
@manuelvicnt #DroidconBos T H R E A D I N G Single.zip( Single.just(3), Single.just(4), BiFunction<Int, Int, Int> { n1, n2 -> n1 + n2 } ) .subscribeOn(Schedulers.computation()) .observeOn(Schedulers.io()) .flatMap { n -> Single.just(n * n) } .observeOn(Schedulers.computation()) .flatMap { n -> Single.just(n - 1) } .observeOn(AndroidSchedulers.mainThread()) .subscribe({ println("Finished with result $it") }, { println("Failed with error $it") }) Computation Io
@manuelvicnt #DroidconBos T H R E A D I N G Single.zip( Single.just(3), Single.just(4), BiFunction<Int, Int, Int> { n1, n2 -> n1 + n2 } ) .subscribeOn(Schedulers.computation()) .observeOn(Schedulers.io()) .flatMap { n -> Single.just(n * n) } .observeOn(Schedulers.computation()) .flatMap { n -> Single.just(n - 1) } .observeOn(AndroidSchedulers.mainThread()) .subscribe({ println("Finished with result $it") }, { println("Failed with error $it") }) Computation Io
@manuelvicnt #DroidconBos T H R E A D I N G Single.zip( Single.just(3), Single.just(4), BiFunction<Int, Int, Int> { n1, n2 -> n1 + n2 } ) .subscribeOn(Schedulers.computation()) .observeOn(Schedulers.io()) .flatMap { n -> Single.just(n * n) } .observeOn(Schedulers.computation()) .flatMap { n -> Single.just(n - 1) } .observeOn(AndroidSchedulers.mainThread()) .subscribe({ println("Finished with result $it") }, { println("Failed with error $it") }) Computation Io
@manuelvicnt #DroidconBos T H R E A D I N G Single.zip( Single.just(3), Single.just(4), BiFunction<Int, Int, Int> { n1, n2 -> n1 + n2 } ) .subscribeOn(Schedulers.computation()) .observeOn(Schedulers.io()) .flatMap { n -> Single.just(n * n) } .observeOn(Schedulers.computation()) .flatMap { n -> Single.just(n - 1) } .observeOn(AndroidSchedulers.mainThread()) .subscribe({ println("Finished with result $it") }, { println("Failed with error $it") }) Computation Io Main Thread
@manuelvicnt #DroidconBos T H R E A D I N G I N C O R O U T I N E S
@manuelvicnt #DroidconBos T H R E A D I N G I N C O R O U T I N E S • It is defined in the CoroutineContext with a value for the key ContinuationInterceptor
@manuelvicnt #DroidconBos T H R E A D I N G I N C O R O U T I N E S • It is defined in the CoroutineContext with a value for the key ContinuationInterceptor • Specified with a CoroutineDispatcher • Specific Thread • Thread Pool
@manuelvicnt #DroidconBos T H R E A D I N G I N C O R O U T I N E S • Some values: • CommonPool • UI (Android) • Unconfined
@manuelvicnt #DroidconBos T H R E A D I N G I N C O R O U T I N E S
@manuelvicnt #DroidconBos T H R E A D I N G I N C O R O U T I N E S • Create your own ThreadPoolDispatcher
@manuelvicnt #DroidconBos T H R E A D I N G I N C O R O U T I N E S • Create your own ThreadPoolDispatcher • NewSingleThreadContext val coroutineDispatcher = newSingleThreadContext("Name")
@manuelvicnt #DroidconBos T H R E A D I N G I N C O R O U T I N E S • Create your own ThreadPoolDispatcher • NewSingleThreadContext • NewFixedThreadPoolContext ••val coroutineDispatcher = newFixedThreadPoolContext(4, "Name") val coroutineDispatcher = newSingleThreadContext("Name")
@manuelvicnt #DroidconBos T H R E A D I N G launch(CommonPool) { val deferred1 = async(coroutineContext) { 3 } val deferred2 = async(coroutineContext) { 4 } var result = deferred1.await() + deferred2.await() launch(newSingleThreadContext("CustomThread")) { result = result * result - 1 }.join() withContext(UI) { println("Finished with result $result") } }
@manuelvicnt #DroidconBos T H R E A D I N G launch(CommonPool) { val deferred1 = async(coroutineContext) { 3 } val deferred2 = async(coroutineContext) { 4 } var result = deferred1.await() + deferred2.await() launch(newSingleThreadContext("CustomThread")) { result = result * result - 1 }.join() withContext(UI) { println("Finished with result $result") } }
@manuelvicnt #DroidconBos T H R E A D I N G launch(CommonPool) { val deferred1 = async(coroutineContext) { 3 } val deferred2 = async(coroutineContext) { 4 } var result = deferred1.await() + deferred2.await() launch(newSingleThreadContext("CustomThread")) { result = result * result - 1 }.join() withContext(UI) { println("Finished with result $result") } }
@manuelvicnt #DroidconBos T H R E A D I N G launch(CommonPool) { val deferred1 = async(coroutineContext) { 3 } val deferred2 = async(coroutineContext) { 4 } var result = deferred1.await() + deferred2.await() launch(newSingleThreadContext("CustomThread")) { result = result * result - 1 }.join() withContext(UI) { println("Finished with result $result") } } CommonPool
@manuelvicnt #DroidconBos T H R E A D I N G launch(CommonPool) { val deferred1 = async(coroutineContext) { 3 } val deferred2 = async(coroutineContext) { 4 } var result = deferred1.await() + deferred2.await() launch(newSingleThreadContext("CustomThread")) { result = result * result - 1 }.join() withContext(UI) { println("Finished with result $result") } } CommonPool
@manuelvicnt #DroidconBos T H R E A D I N G launch(CommonPool) { val deferred1 = async(coroutineContext) { 3 } val deferred2 = async(coroutineContext) { 4 } var result = deferred1.await() + deferred2.await() launch(newSingleThreadContext("CustomThread")) { result = result * result - 1 }.join() withContext(UI) { println("Finished with result $result") } } CommonPool CustomThread
@manuelvicnt #DroidconBos T H R E A D I N G launch(CommonPool) { val deferred1 = async(coroutineContext) { 3 } val deferred2 = async(coroutineContext) { 4 } var result = deferred1.await() + deferred2.await() launch(newSingleThreadContext("CustomThread")) { result = result * result - 1 }.join() withContext(UI) { println("Finished with result $result") } } CommonPool CustomThread
@manuelvicnt #DroidconBos T H R E A D I N G launch(CommonPool) { val deferred1 = async(coroutineContext) { 3 } val deferred2 = async(coroutineContext) { 4 } var result = deferred1.await() + deferred2.await() launch(newSingleThreadContext("CustomThread")) { result = result * result - 1 }.join() withContext(UI) { println("Finished with result $result") } } CommonPool CustomThread UI
M AT H A P P M V I A R C H I T E C T U R E
Coroutines and RxJava - An Asynchronicity Comparison
@manuelvicnt #DroidconBos M AT H A P P • Three Projects. Implemented with: • Coroutines • RxJava • Coroutines/RxJava Interop
@manuelvicnt #DroidconBos M AT H A P P • MVI • Architecture Components ViewModels • Survives Configuration Changes
R E S T O R E S TAT E
@manuelvicnt #DroidconBos M V I A R C H I T E C T U R E V I E W V I E W M O D E L 1. User Input 2. User Action 3. Process Result4. View State 5. Render State
@manuelvicnt #DroidconBos M V I A R C H I T E C T U R E V I E W V I E W M O D E L 1. User Input 2. User Action 3. Process Result4. View State 5. Render State ?
@manuelvicnt #DroidconBos M V I A R C H I T E C T U R E V I E W V I E W M O D E L 1. User Input 2. User Action 3. Process Result4. View State 5. Render State ? ?
@manuelvicnt #DroidconBos R X A R C H I T E C T U R E V I E W V I E W M O D E L 1. User Input 2. User Action S U B J E C T * S U B J E C T * 3. Process Result4. View State 5. Render State * Not optimal
@manuelvicnt #DroidconBos R X A R C H I T E C T U R E V I E W V I E W M O D E L 2. User Action R X R E L AY O B S E R VA B L E 4. View State Exposes an Observable but implemented with a Subject so View cannot call onNext() RxRelay to avoid the View calling onComplete()
@manuelvicnt #DroidconBos C O R O U T I N E S A R C H I T E C T U R E V I E W V I E W M O D E L 1. User Input 2. User Action A C T O R C B C * * ConflatedBroadcastChannel 3. Process Result4. View State 5. Render State
@manuelvicnt #DroidconBos C O M M O N I M P L E M E N TAT I O N sealed class MainUserAction { class Calculate( val number: Long ) : MainUserAction() class FunFactEnabled( val enabled: Boolean ) : MainUserAction() }
@manuelvicnt #DroidconBos C O M M O N I M P L E M E N TAT I O N sealed class MainViewState { object Loading : MainViewState() class Rendered( val fibonacciNumber: Long, val funFact: String ) : MainViewState() object WrongInputError : MainViewState() object RequestError : MainViewState() }
@manuelvicnt #DroidconBos V I E W M O D E L • Extends from ViewModel in Architecture Components • Receives User Actions • Processes User Action • Notifies View with the ViewState
@manuelvicnt #DroidconBos R X V I E W M O D E L
@manuelvicnt #DroidconBos R X V I E W M O D E L • Receives User Actions val userActionSubject: PublishSubject<MainUserAction>
@manuelvicnt #DroidconBos R X V I E W M O D E L • Receives User Actions • Notifies View with the ViewState val viewStateSubject: BehaviorSubject<MainViewState> val userActionSubject: PublishSubject<MainUserAction>
@manuelvicnt #DroidconBos R X V I E W M O D E L init { userActionSubject .subscribeOn(Schedulers.computation()) .subscribe({ when (it) { is MainUserAction.Calculate -> { if (it.number <= 0) { viewStateSubject. onNext(MainViewState.WrongInputError) } else { viewStateSubject.onNext(MainViewState.Loading) processCalculation(it) } } is MainUserAction.FunFactEnabled -> { askForFunFact = it.enabled } } }) }
@manuelvicnt #DroidconBos R X V I E W M O D E L init { userActionSubject .subscribeOn(Schedulers.computation()) .subscribe({ when (it) { is MainUserAction.Calculate -> { if (it.number <= 0) { viewStateSubject. onNext(MainViewState.WrongInputError) } else { viewStateSubject.onNext(MainViewState.Loading) processCalculation(it) } } is MainUserAction.FunFactEnabled -> { askForFunFact = it.enabled } } }) }
@manuelvicnt #DroidconBos R X V I E W M O D E L init { userActionSubject .subscribeOn(Schedulers.computation()) .subscribe({ when (it) { is MainUserAction.Calculate -> { if (it.number <= 0) { viewStateSubject. onNext(MainViewState.WrongInputError) } else { viewStateSubject.onNext(MainViewState.Loading) processCalculation(it) } } is MainUserAction.FunFactEnabled -> { askForFunFact = it.enabled } } }) }
@manuelvicnt #DroidconBos R X V I E W M O D E L init { userActionSubject .subscribeOn(Schedulers.computation()) .subscribe({ when (it) { is MainUserAction.Calculate -> { if (it.number <= 0) { viewStateSubject. onNext(MainViewState.WrongInputError) } else { viewStateSubject.onNext(MainViewState.Loading) processCalculation(it) } } is MainUserAction.FunFactEnabled -> { askForFunFact = it.enabled } } }) }
@manuelvicnt #DroidconBos R X V I E W M O D E L init { userActionSubject .subscribeOn(Schedulers.computation()) .subscribe({ when (it) { is MainUserAction.Calculate -> { if (it.number <= 0) { viewStateSubject. onNext(MainViewState.WrongInputError) } else { viewStateSubject.onNext(MainViewState.Loading) processCalculation(it) } } is MainUserAction.FunFactEnabled -> { askForFunFact = it.enabled } } }) }
@manuelvicnt #DroidconBos • Clean up when it’s not longer needed R X V I E W M O D E L override fun onCleared() { userActionSubject.onComplete() viewStateSubject.onComplete() super.onCleared() }
@manuelvicnt #DroidconBos C O R O U T I N E S V I E W M O D E L
@manuelvicnt #DroidconBos C O R O U T I N E S V I E W M O D E L • Receives User Actions val userActionActor = actor<MainUserAction>(CommonPool, parent = parentJob)
@manuelvicnt #DroidconBos C O R O U T I N E S V I E W M O D E L • Receives User Actions • Notifies View with the ViewState val viewStateChannel = ConflatedBroadcastChannel<MainViewState>() val userActionActor = actor<MainUserAction>(CommonPool, parent = parentJob)
@manuelvicnt #DroidconBos C O R O U T I N E S V I E W M O D E L private val parentJob = Job() val userActionActor = actor<MainUserAction>( CommonPool, parent = parentJob ) { for (msg in channel) { // iterate over incoming messages when (msg) { is MainUserAction.Calculate -> { if (msg.number <= 0) { viewStateChannel.offer(MainViewState.WrongInputError) } else { viewStateChannel.offer(MainViewState.Loading) processCalculation(msg) } } is MainUserAction.FunFactEnabled -> { askForFunFact = msg.enabled } } } }
@manuelvicnt #DroidconBos C O R O U T I N E S V I E W M O D E L private val parentJob = Job() val userActionActor = actor<MainUserAction>( CommonPool, parent = parentJob ) { for (msg in channel) { // iterate over incoming messages when (msg) { is MainUserAction.Calculate -> { if (msg.number <= 0) { viewStateChannel.offer(MainViewState.WrongInputError) } else { viewStateChannel.offer(MainViewState.Loading) processCalculation(msg) } } is MainUserAction.FunFactEnabled -> { askForFunFact = msg.enabled } } } }
@manuelvicnt #DroidconBos C O R O U T I N E S V I E W M O D E L private val parentJob = Job() val userActionActor = actor<MainUserAction>( CommonPool, parent = parentJob ) { for (msg in channel) { // iterate over incoming messages when (msg) { is MainUserAction.Calculate -> { if (msg.number <= 0) { viewStateChannel.offer(MainViewState.WrongInputError) } else { viewStateChannel.offer(MainViewState.Loading) processCalculation(msg) } } is MainUserAction.FunFactEnabled -> { askForFunFact = msg.enabled } } } }
@manuelvicnt #DroidconBos C O R O U T I N E S V I E W M O D E L private val parentJob = Job() val userActionActor = actor<MainUserAction>( CommonPool, parent = parentJob ) { for (msg in channel) { // iterate over incoming messages when (msg) { is MainUserAction.Calculate -> { if (msg.number <= 0) { viewStateChannel.offer(MainViewState.WrongInputError) } else { viewStateChannel.offer(MainViewState.Loading) processCalculation(msg) } } is MainUserAction.FunFactEnabled -> { askForFunFact = msg.enabled } } } }
@manuelvicnt #DroidconBos C O R O U T I N E S V I E W M O D E L private val parentJob = Job() val userActionActor = actor<MainUserAction>( CommonPool, parent = parentJob ) { for (msg in channel) { // iterate over incoming messages when (msg) { is MainUserAction.Calculate -> { if (msg.number <= 0) { viewStateChannel.offer(MainViewState.WrongInputError) } else { viewStateChannel.offer(MainViewState.Loading) processCalculation(msg) } } is MainUserAction.FunFactEnabled -> { askForFunFact = msg.enabled } } } }
@manuelvicnt #DroidconBos • Clean up when it’s not longer needed C O R O U T I N E S V I E W M O D E L override fun onCleared() { viewStateChannel.close() parentJob.cancel() // Cancels the Actor super.onCleared() }
@manuelvicnt #DroidconBos V I E W • Listens for User Events • Talks to ViewModel to process Input • Renders ViewState
@manuelvicnt #DroidconBos R X J AVA V I E W • Listens for User Events • Talks to ViewModel to process Input private fun setupViews() { calcButton.setOnClickListener { viewModel.userActionSubject.onNext( MainUserAction.Calculate( input.text.toString().toLong())) } funFact.setOnCheckedChangeListener { _, isChecked -> viewModel.userActionSubject.onNext( MainUserAction.FunFactEnabled(isChecked)) } }
@manuelvicnt #DroidconBos R X J AVA V I E W • Listens for User Events • Talks to ViewModel to process Input private fun setupViews() { calcButton.setOnClickListener { viewModel.userActionSubject.onNext( MainUserAction.Calculate( input.text.toString().toLong())) } funFact.setOnCheckedChangeListener { _, isChecked -> viewModel.userActionSubject.onNext( MainUserAction.FunFactEnabled(isChecked)) } }
@manuelvicnt #DroidconBos R X J AVA V I E W • Listens for User Events • Talks to ViewModel to process Input private fun setupViews() { calcButton.setOnClickListener { viewModel.userActionSubject.onNext( MainUserAction.Calculate( input.text.toString().toLong())) } funFact.setOnCheckedChangeListener { _, isChecked -> viewModel.userActionSubject.onNext( MainUserAction.FunFactEnabled(isChecked)) } }
@manuelvicnt #DroidconBos R X J AVA V I E W private fun listenViewModel() { viewStateDisposable = viewModel.viewStateObservable .observeOn(AndroidSchedulers.mainThread()) .subscribe({ when (it) { MainViewState.Loading -> { progressBar.visibility = View.VISIBLE result.text = "Loading..." funFactText.text = "" } MainViewState.WrongInputError -> { showError() } … } }) }
@manuelvicnt #DroidconBos R X J AVA V I E W • Renders ViewState private fun listenViewModel() { viewStateDisposable = viewModel.viewStateObservable .observeOn(AndroidSchedulers.mainThread()) .subscribe({ when (it) { MainViewState.Loading -> { progressBar.visibility = View.VISIBLE result.text = "Loading..." funFactText.text = "" } MainViewState.WrongInputError -> { showError() } … } }) }
@manuelvicnt #DroidconBos R X J AVA V I E W private fun listenViewModel() { viewStateDisposable = viewModel.viewStateObservable .observeOn(AndroidSchedulers.mainThread()) .subscribe({ when (it) { MainViewState.Loading -> { progressBar.visibility = View.VISIBLE result.text = "Loading..." funFactText.text = "" } MainViewState.WrongInputError -> { showError() } … } }) }
@manuelvicnt #DroidconBos R X J AVA V I E W • Renders ViewState private fun listenViewModel() { viewStateDisposable = viewModel.viewStateObservable .observeOn(AndroidSchedulers.mainThread()) .subscribe({ when (it) { MainViewState.Loading -> { progressBar.visibility = View.VISIBLE result.text = "Loading..." funFactText.text = "" } MainViewState.WrongInputError -> { showError() } … } }) }
@manuelvicnt #DroidconBos R X J AVA V I E W private fun listenViewModel() { viewStateDisposable = viewModel.viewStateObservable .observeOn(AndroidSchedulers.mainThread()) .subscribe({ when (it) { MainViewState.Loading -> { progressBar.visibility = View.VISIBLE result.text = "Loading..." funFactText.text = "" } MainViewState.WrongInputError -> { showError() } … } }) }
@manuelvicnt #DroidconBos R X J AVA V I E W • Renders ViewState private fun listenViewModel() { viewStateDisposable = viewModel.viewStateObservable .observeOn(AndroidSchedulers.mainThread()) .subscribe({ when (it) { MainViewState.Loading -> { progressBar.visibility = View.VISIBLE result.text = "Loading..." funFactText.text = "" } MainViewState.WrongInputError -> { showError() } … } }) }
@manuelvicnt #DroidconBos R X J AVA V I E W override fun onStart() { super.onStart() listenViewModel() // Registers to ViewState Observable } override fun onStop() { if (viewStateDisposable?.isDisposed == false) { viewStateDisposable?.dispose() } super.onStop() }
@manuelvicnt #DroidconBos R X J AVA V I E W • View Lifecycle override fun onStart() { super.onStart() listenViewModel() // Registers to ViewState Observable } override fun onStop() { if (viewStateDisposable?.isDisposed == false) { viewStateDisposable?.dispose() } super.onStop() }
@manuelvicnt #DroidconBos C O R O U T I N E S V I E W • Listens for User Events • Talks to ViewModel to process Input private fun setupViews() { calcButton.setOnClickListener { viewModel.userActionActor.offer( MainUserAction.Calculate( input.text.toString().toLong())) } funFact.setOnCheckedChangeListener { _, isChecked -> viewModel.userActionActor.offer( MainUserAction.FunFactEnabled(isChecked)) } }
@manuelvicnt #DroidconBos C O R O U T I N E S V I E W • Listens for User Events • Talks to ViewModel to process Input private fun setupViews() { calcButton.setOnClickListener { viewModel.userActionActor.offer( MainUserAction.Calculate( input.text.toString().toLong())) } funFact.setOnCheckedChangeListener { _, isChecked -> viewModel.userActionActor.offer( MainUserAction.FunFactEnabled(isChecked)) } }
@manuelvicnt #DroidconBos C O R O U T I N E S V I E W • Listens for User Events • Talks to ViewModel to process Input private fun setupViews() { calcButton.setOnClickListener { viewModel.userActionActor.offer( MainUserAction.Calculate( input.text.toString().toLong())) } funFact.setOnCheckedChangeListener { _, isChecked -> viewModel.userActionActor.offer( MainUserAction.FunFactEnabled(isChecked)) } }
@manuelvicnt #DroidconBos C O R O U T I N E S V I E W private val parentJob = Job() private fun listenViewModel() { // Launch on the CommonPool to not block the MainThread launch(parentJob + CommonPool) { viewModel.viewStateChannel.consumeEach { withContext(UI) { when (it) { MainViewState.Loading -> { progressBar.visibility = View.VISIBLE result.text = "Loading..." funFactText.text = "" } … } } } } }
@manuelvicnt #DroidconBos C O R O U T I N E S V I E W • Renders ViewState private val parentJob = Job() private fun listenViewModel() { // Launch on the CommonPool to not block the MainThread launch(parentJob + CommonPool) { viewModel.viewStateChannel.consumeEach { withContext(UI) { when (it) { MainViewState.Loading -> { progressBar.visibility = View.VISIBLE result.text = "Loading..." funFactText.text = "" } … } } } } }
@manuelvicnt #DroidconBos C O R O U T I N E S V I E W private val parentJob = Job() private fun listenViewModel() { // Launch on the CommonPool to not block the MainThread launch(parentJob + CommonPool) { viewModel.viewStateChannel.consumeEach { withContext(UI) { when (it) { MainViewState.Loading -> { progressBar.visibility = View.VISIBLE result.text = "Loading..." funFactText.text = "" } … } } } } }
@manuelvicnt #DroidconBos C O R O U T I N E S V I E W • Renders ViewState private val parentJob = Job() private fun listenViewModel() { // Launch on the CommonPool to not block the MainThread launch(parentJob + CommonPool) { viewModel.viewStateChannel.consumeEach { withContext(UI) { when (it) { MainViewState.Loading -> { progressBar.visibility = View.VISIBLE result.text = "Loading..." funFactText.text = "" } … } } } } }
@manuelvicnt #DroidconBos C O R O U T I N E S V I E W private val parentJob = Job() private fun listenViewModel() { // Launch on the CommonPool to not block the MainThread launch(parentJob + CommonPool) { viewModel.viewStateChannel.consumeEach { withContext(UI) { when (it) { MainViewState.Loading -> { progressBar.visibility = View.VISIBLE result.text = "Loading..." funFactText.text = "" } … } } } } }
@manuelvicnt #DroidconBos C O R O U T I N E S V I E W • Renders ViewState private val parentJob = Job() private fun listenViewModel() { // Launch on the CommonPool to not block the MainThread launch(parentJob + CommonPool) { viewModel.viewStateChannel.consumeEach { withContext(UI) { when (it) { MainViewState.Loading -> { progressBar.visibility = View.VISIBLE result.text = "Loading..." funFactText.text = "" } … } } } } }
@manuelvicnt #DroidconBos C O R O U T I N E S V I E W private val parentJob = Job() private fun listenViewModel() { // Launch on the CommonPool to not block the MainThread launch(parentJob + CommonPool) { viewModel.viewStateChannel.consumeEach { withContext(UI) { when (it) { MainViewState.Loading -> { progressBar.visibility = View.VISIBLE result.text = "Loading..." funFactText.text = "" } … } } } } }
@manuelvicnt #DroidconBos C O R O U T I N E S V I E W • Renders ViewState private val parentJob = Job() private fun listenViewModel() { // Launch on the CommonPool to not block the MainThread launch(parentJob + CommonPool) { viewModel.viewStateChannel.consumeEach { withContext(UI) { when (it) { MainViewState.Loading -> { progressBar.visibility = View.VISIBLE result.text = "Loading..." funFactText.text = "" } … } } } } }
@manuelvicnt #DroidconBos C O R O U T I N E S V I E W override fun onStart() { super.onStart() listenViewModel() // Listens to ViewStateChannel } override fun onStop() { parentJob.cancel() super.onStop() }
@manuelvicnt #DroidconBos C O R O U T I N E S V I E W • View Lifecycle override fun onStart() { super.onStart() listenViewModel() // Listens to ViewStateChannel } override fun onStop() { parentJob.cancel() super.onStop() }
S H O W M E S O M E N U M B E R S
@manuelvicnt #DroidconBos P E R F O R M A N C E
@manuelvicnt #DroidconBos P E R F O R M A N C E • Roughly the same • Not difficult enough to compare
@manuelvicnt #DroidconBos S I Z E Measure Coroutines RxJava Interop APK Size 2.4MB 2.9MB 3.1MB Method Count 29,131 37,271 39,590
@manuelvicnt #DroidconBos G I T H U B L I N K S manuelvicnt/MathCoroutines Coroutines manuelvicnt/MathRxJava RxJava manuelvicnt/MathRxCoroutines Coroutines and RxJava
@manuelvicnt #DroidconBos C O N C L U S I O N
@manuelvicnt #DroidconBos C O N C L U S I O N • Both libraries provide a way to do Asynchronous Programming • If you are a RxJava expert, no need to switch • If you struggle with RxJava, Coroutines is another option you can try • For new Android developers, Coroutines has a lower learning curve
C O R O U T I N E S A N D R X J AVA A N A S Y N C H R O N I C I T Y C O M PA R I S O N @ M A N U E LV I C N T A N Y Q U E S T I O N S ? M A N U E L V I C E N T E V I V O

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Coroutines and RxJava - An Asynchronicity Comparison

  • 1. C O R O U T I N E S A N D R X J AVA A N A S Y N C H R O N I C I T Y C O M PA R I S O N M A N U E L V I C E N T E V I V O @ M A N U E LV I C N T
  • 2. @manuelvicnt #DroidconBos A G E N D A • Coroutines Recap • RxJava & Coroutines concepts • Build an App
  • 3. @manuelvicnt #DroidconBos G O A L S • Learn Coroutines with basic RxJava knowledge • Compare both libraries on different topics • Use what we learned to build the App • Code available
  • 5. @manuelvicnt #DroidconBos I N T E N D E D A U D I E N C E • Able to read Kotlin code • Basic RxJava experience • Coroutines 101 • You want to learn differences and similarities between RxJava and Coroutines
  • 6. @manuelvicnt #DroidconBos I H E A R D C O R O U T I N E S ? • From the Kotlin documentation… • Coroutines simplify asynchronous programming • Code can be expressed sequentially and the library handles the asynchronous code for us • Computations can be suspended without blocking a Thread
  • 7. @manuelvicnt #DroidconBos I H E A R D C O R O U T I N E S ? • From the Kotlin documentation… • Coroutines simplify asynchronous programming • Code can be expressed sequentially and the library handles the asynchronous code for us • Computations can be suspended without blocking a Thread
  • 8. @manuelvicnt #DroidconBos I H E A R D C O R O U T I N E S ? • From the Kotlin documentation… • Coroutines simplify asynchronous programming • Code can be expressed sequentially and the library handles the asynchronous code for us • Computations can be suspended without blocking a Thread
  • 9. I WA N T T O P L AY A G A M E
  • 10. @manuelvicnt #DroidconBos What is this? launch(CommonPool) { heavyComputation() }
  • 11. @manuelvicnt #DroidconBos What is this? launch(CommonPool) { heavyComputation() } Coroutine
  • 12. @manuelvicnt #DroidconBos What is this? launch(CommonPool) { heavyComputation() }
  • 13. @manuelvicnt #DroidconBos What is this? launch(CommonPool) { heavyComputation() } Coroutine Builder
  • 14. @manuelvicnt #DroidconBos What is this? launch(CommonPool) { heavyComputation() }
  • 15. @manuelvicnt #DroidconBos What is this? launch(CommonPool) { heavyComputation() } Coroutine Context
  • 16. @manuelvicnt #DroidconBos What is this? launch(CommonPool) { heavyComputation() }
  • 17. @manuelvicnt #DroidconBos What is this? launch(CommonPool) { heavyComputation() } Suspending Lambda
  • 18. @manuelvicnt #DroidconBos What is this? launch(CommonPool) { heavyComputation() val data = makeNetworkRequest() updateDB(data) } Suspending Lambda
  • 19. @manuelvicnt #DroidconBos What is this? launch(CommonPool) { heavyComputation() val data = makeNetworkRequest() updateDB(data) } Suspending Lambda
  • 20. @manuelvicnt #DroidconBos What is this? launch(CommonPool) { heavyComputation() val data = makeNetworkRequest() updateDB(data) } Suspending Lambda
  • 21. @manuelvicnt #DroidconBos What is this? launch(CommonPool) { heavyComputation() val data = makeNetworkRequest() updateDB(data) } Suspending Lambda
  • 22. @manuelvicnt #DroidconBos What is this? launch(CommonPool) { heavyComputation() val data = makeNetworkRequest() updateDB(data) } Suspending Lambda
  • 23. @manuelvicnt #DroidconBos What is this? launch(CommonPool) { heavyComputation() val data = makeNetworkRequest() updateDB(data) } Suspending Lambda
  • 24. @manuelvicnt #DroidconBos What is this? launch(CommonPool) { heavyComputation() val data = makeNetworkRequest() updateDB(data) } Suspending Lambda
  • 25. @manuelvicnt #DroidconBos What is this? launch(CommonPool) { heavyComputation() val data = makeNetworkRequest() updateDB(data) } Suspending Lambda
  • 26. C O R O U T I N E S R E C A P C O M P L E T E D
  • 27. C O R O U T I N E S - R X J AVA C O M PA R I S O N
  • 28. C A N C E L E X E C U T I O N
  • 30. @manuelvicnt #DroidconBos With Disposables How to cancel an Observable? val disposable: Disposable = Observable.interval(1, TimeUnit.SECONDS) .subscribe() disposable.dispose()
  • 31. @manuelvicnt #DroidconBos With Disposables How to cancel an Observable? val disposable: Disposable = Observable.interval(1, TimeUnit.SECONDS) .subscribe() disposable.dispose()
  • 32. @manuelvicnt #DroidconBos With the Coroutine Job (from the Coroutine Context) How to cancel a Coroutine?
  • 33. @manuelvicnt #DroidconBos With the Coroutine Job (from the Coroutine Context) How to cancel a Coroutine? val job = launch(CommonPool) { // my suspending block } job.cancel()
  • 34. @manuelvicnt #DroidconBos With the Coroutine Job (from the Coroutine Context) How to cancel a Coroutine? val parentJob = Job() launch(parentJob + CommonPool) { // my suspending block } parentJob.cancel()
  • 35. @manuelvicnt #DroidconBos With the Coroutine Job (from the Coroutine Context) How to cancel a Coroutine? val parentJob = Job() launch(CommonPool, parent = parentJob) { // my suspending block } parentJob.cancel()
  • 36. C H A N N E L S
  • 37. @manuelvicnt #DroidconBos C H A N N E L S • Transfer stream of values • Similar to Reactive Streams Publisher or RxJava Observable/Flowable
  • 38. @manuelvicnt #DroidconBos C H A N N E L S • Transfer stream of values • Similar to Reactive Streams Publisher or RxJava Observable/Flowable Observable.create<Int> { emitter -> for (i in 1..5) { emitter.onNext(i) } emitter.onComplete() }
  • 39. @manuelvicnt #DroidconBos Observable.create<Int> { emitter -> for (i in 1..5) { emitter.onNext(i) } emitter.onComplete() } C H A N N E L S
  • 40. @manuelvicnt #DroidconBos Observable.create<Int> { emitter -> for (i in 1..5) { emitter.onNext(i) } emitter.onComplete() } C H A N N E L S
  • 41. @manuelvicnt #DroidconBos Observable.create<Int> { emitter -> for (i in 1..5) { emitter.onNext(i) } emitter.onComplete() } C H A N N E L S
  • 42. @manuelvicnt #DroidconBos Observable.create<Int> { emitter -> for (i in 1..5) { emitter.onNext(i) } emitter.onComplete() }.subscribe() C H A N N E L S
  • 43. @manuelvicnt #DroidconBos C H A N N E L S Observable.create<Int> { emitter -> for (i in 1..5) { emitter.onNext(i) } emitter.onComplete() }.subscribe()
  • 44. @manuelvicnt #DroidconBos C H A N N E L S Observer Timeline Observable.create<Int> { emitter -> for (i in 1..5) { emitter.onNext(i) } emitter.onComplete() }.subscribe()
  • 45. @manuelvicnt #DroidconBos C H A N N E L S Observer Timeline 1 Observable.create<Int> { emitter -> for (i in 1..5) { emitter.onNext(i) } emitter.onComplete() }.subscribe()
  • 46. @manuelvicnt #DroidconBos C H A N N E L S Observer Timeline 1 2 Observable.create<Int> { emitter -> for (i in 1..5) { emitter.onNext(i) } emitter.onComplete() }.subscribe()
  • 47. @manuelvicnt #DroidconBos C H A N N E L S Observer Timeline 1 2 3 Observable.create<Int> { emitter -> for (i in 1..5) { emitter.onNext(i) } emitter.onComplete() }.subscribe()
  • 48. @manuelvicnt #DroidconBos C H A N N E L S Observer Timeline 1 2 3 4 Observable.create<Int> { emitter -> for (i in 1..5) { emitter.onNext(i) } emitter.onComplete() }.subscribe()
  • 49. @manuelvicnt #DroidconBos C H A N N E L S Observer Timeline 1 2 3 4 5 Observable.create<Int> { emitter -> for (i in 1..5) { emitter.onNext(i) } emitter.onComplete() }.subscribe()
  • 50. @manuelvicnt #DroidconBos C H A N N E L S Observer Timeline 1 2 3 4 5 Observable.create<Int> { emitter -> for (i in 1..5) { emitter.onNext(i) } emitter.onComplete() }.subscribe()
  • 51. @manuelvicnt #DroidconBos C H A N N E L S Observer Timeline 1 2 3 4 5 Observable.create<Int> { emitter -> for (i in 1..5) { emitter.onNext(i) } emitter.onComplete() }.subscribe()
  • 52. @manuelvicnt #DroidconBos C H A N N E L S Observer Timeline 1 2 3 4 5 Observer 2 Timeline Observable.create<Int> { emitter -> for (i in 1..5) { emitter.onNext(i) } emitter.onComplete() }.subscribe()
  • 53. @manuelvicnt #DroidconBos C H A N N E L S Observer Timeline 1 2 3 4 5 Observer 2 Timeline 1 Observable.create<Int> { emitter -> for (i in 1..5) { emitter.onNext(i) } emitter.onComplete() }.subscribe()
  • 54. @manuelvicnt #DroidconBos C H A N N E L S Observer Timeline 1 2 3 4 5 Observer 2 Timeline 1 2 Observable.create<Int> { emitter -> for (i in 1..5) { emitter.onNext(i) } emitter.onComplete() }.subscribe()
  • 55. @manuelvicnt #DroidconBos C H A N N E L S Observer Timeline 1 2 3 4 5 Observer 2 Timeline 1 2 3 Observable.create<Int> { emitter -> for (i in 1..5) { emitter.onNext(i) } emitter.onComplete() }.subscribe()
  • 56. @manuelvicnt #DroidconBos C H A N N E L S Observer Timeline 1 2 3 4 5 Observer 2 Timeline 1 2 3 4 Observable.create<Int> { emitter -> for (i in 1..5) { emitter.onNext(i) } emitter.onComplete() }.subscribe()
  • 57. @manuelvicnt #DroidconBos C H A N N E L S Observer Timeline 1 2 3 4 5 Observer 2 Timeline 1 2 3 4 5 Observable.create<Int> { emitter -> for (i in 1..5) { emitter.onNext(i) } emitter.onComplete() }.subscribe()
  • 58. @manuelvicnt #DroidconBos C H A N N E L S Observer Timeline 1 2 3 4 5 Observer 2 Timeline 1 2 3 4 5 Observable.create<Int> { emitter -> for (i in 1..5) { emitter.onNext(i) } emitter.onComplete() }.subscribe()
  • 59. @manuelvicnt #DroidconBos C H A N N E L S • Transfer stream of values • Can be shared between different Coroutines • By default, channel capacity == 1
  • 60. @manuelvicnt #DroidconBos C H A N N E L S • Transfer stream of values • Can be shared between different Coroutines • By default, channel capacity == 1 interface Channel<E> : SendChannel<E>, ReceiveChannel<E>
  • 61. @manuelvicnt #DroidconBos interface Channel<E> : SendChannel<E>, ReceiveChannel<E> C H A N N E L S
  • 62. @manuelvicnt #DroidconBos interface Channel<E> : SendChannel<E>, ReceiveChannel<E> public interface SendChannel<in E> { public suspend fun send(element: E) public fun offer(element: E) public fun close(cause: Throwable? = null): Boolean } public interface ReceiveChannel<out E> { public suspend fun receive(): E public fun close(cause: Throwable? = null): Boolean } C H A N N E L S
  • 63. @manuelvicnt #DroidconBos interface Channel<E> : SendChannel<E>, ReceiveChannel<E> public interface SendChannel<in E> { public suspend fun send(element: E) public fun offer(element: E) public fun close(cause: Throwable? = null): Boolean } public interface ReceiveChannel<out E> { public suspend fun receive(): E public fun close(cause: Throwable? = null): Boolean } C H A N N E L S
  • 64. @manuelvicnt #DroidconBos interface Channel<E> : SendChannel<E>, ReceiveChannel<E> public interface SendChannel<in E> { public suspend fun send(element: E) public fun offer(element: E) public fun close(cause: Throwable? = null): Boolean } public interface ReceiveChannel<out E> { public suspend fun receive(): E public fun close(cause: Throwable? = null): Boolean } C H A N N E L S
  • 65. @manuelvicnt #DroidconBos interface Channel<E> : SendChannel<E>, ReceiveChannel<E> public interface SendChannel<in E> { public suspend fun send(element: E) public fun offer(element: E) public fun close(cause: Throwable? = null): Boolean } public interface ReceiveChannel<out E> { public suspend fun receive(): E public fun close(cause: Throwable? = null): Boolean } C H A N N E L S
  • 66. @manuelvicnt #DroidconBos C H A N N E L S val channel = Channel<Int>() Channel
  • 67. @manuelvicnt #DroidconBos C H A N N E L S val channel = Channel<Int>() Channel launch { channel.send(1) }
  • 68. @manuelvicnt #DroidconBos C H A N N E L S val channel = Channel<Int>() Channel 1 launch { channel.send(1) }
  • 69. @manuelvicnt #DroidconBos C H A N N E L S val channel = Channel<Int>() Channel 1 launch { channel.send(1) } launch { val value = channel.receive() }
  • 70. @manuelvicnt #DroidconBos C H A N N E L S val channel = Channel<Int>() Channel 1 launch { channel.send(1) } launch { val value = channel.receive() }
  • 71. @manuelvicnt #DroidconBos C H A N N E L S val channel = Channel<Int>() Channel CapacityChannel 1
  • 72. @manuelvicnt #DroidconBos C H A N N E L S val channel = Channel<Int>() Channel Capacity launch { channel.send(1) channel.send(2) } Channel 1
  • 73. @manuelvicnt #DroidconBos C H A N N E L S val channel = Channel<Int>() Channel Capacity launch { channel.send(1) channel.send(2) } Channel 1
  • 74. @manuelvicnt #DroidconBos C H A N N E L S val channel = Channel<Int>() Channel Capacity 1 launch { channel.send(1) channel.send(2) } Channel 0
  • 75. @manuelvicnt #DroidconBos C H A N N E L S val channel = Channel<Int>() Channel Capacity 1 launch { channel.send(1) channel.send(2) } Channel 0
  • 76. @manuelvicnt #DroidconBos C H A N N E L S val channel = Channel<Int>() Channel Capacity 1 launch { channel.send(1) channel.send(2) } Channel 0 // Suspended until the // channel is NOT full
  • 77. @manuelvicnt #DroidconBos C H A N N E L S val channel = Channel<Int>() Channel Capacity 1 launch { channel.send(1) channel.send(2) } Channel 0 // Suspended until the // channel is NOT full launch { val value = channel.receive() }
  • 78. @manuelvicnt #DroidconBos C H A N N E L S val channel = Channel<Int>() Channel Capacity launch { channel.send(1) channel.send(2) } Channel 1 // Suspended until the // channel is NOT full launch { val value = channel.receive() } 1
  • 79. @manuelvicnt #DroidconBos C H A N N E L S val channel = Channel<Int>() Channel Capacity launch { channel.send(1) channel.send(2) } Channel 1 // Suspended until the // channel is NOT full launch { val value = channel.receive() } 1
  • 80. @manuelvicnt #DroidconBos C H A N N E L S val channel = Channel<Int>() Channel Capacity launch { channel.send(1) channel.send(2) } Channel launch { val value = channel.receive() } 11
  • 81. @manuelvicnt #DroidconBos C H A N N E L S val channel = Channel<Int>() Channel Capacity launch { channel.send(1) channel.send(2) } Channel launch { val value = channel.receive() } 11
  • 82. @manuelvicnt #DroidconBos C H A N N E L S val channel = Channel<Int>() Channel Capacity launch { channel.send(1) channel.send(2) } Channel 0 launch { val value = channel.receive() } 21
  • 83. @manuelvicnt #DroidconBos C H A N N E L S val channel = Channel<Int>() launch { for (x in 1..5) channel.send(x) }
  • 84. @manuelvicnt #DroidconBos C H A N N E L S val channel = Channel<Int>() launch { for (x in 1..5) channel.send(x) } launch { for (value in channel) { consumeValue(value) } } Channel
  • 85. @manuelvicnt #DroidconBos C H A N N E L S val channel = Channel<Int>() launch { for (x in 1..5) channel.send(x) } launch { for (value in channel) { consumeValue(value) } } Channel 1
  • 86. @manuelvicnt #DroidconBos C H A N N E L S val channel = Channel<Int>() launch { for (x in 1..5) channel.send(x) } launch { for (value in channel) { consumeValue(value) } } Channel 1 2
  • 87. @manuelvicnt #DroidconBos C H A N N E L S val channel = Channel<Int>() launch { for (x in 1..5) channel.send(x) } launch { for (value in channel) { consumeValue(value) } } Channel 1 2 3
  • 88. @manuelvicnt #DroidconBos C H A N N E L S val channel = Channel<Int>() launch { for (x in 1..5) channel.send(x) } launch { for (value in channel) { consumeValue(value) } } Channel 1 2 3 4
  • 89. @manuelvicnt #DroidconBos C H A N N E L S val channel = Channel<Int>() launch { for (x in 1..5) channel.send(x) } launch { for (value in channel) { consumeValue(value) } } Channel 1 2 3 4 5
  • 90. @manuelvicnt #DroidconBos C H A N N E L S val channel = Channel<Int>() launch { for (x in 1..5) channel.send(x) } launch { for (value in channel) { consumeValue(value) } } Channel 1 2 3 4 5
  • 91. @manuelvicnt #DroidconBos C H A N N E L S Channel 1 2 3 4 5 launch { consumeValue(channel.receive()) }
  • 92. @manuelvicnt #DroidconBos C H A N N E L S Channel 1 2 3 4 5 launch { consumeValue(channel.receive()) }
  • 93. @manuelvicnt #DroidconBos C H A N N E L S Channel 1 2 3 4 5 launch { consumeValue(channel.receive()) }
  • 94. @manuelvicnt #DroidconBos C H A N N E L S Channel 1 2 3 4 5 launch { consumeValue(channel.receive()) } // Suspended until the // channel is NOT empty
  • 95. @manuelvicnt #DroidconBos B U F F E R E D C H A N N E L S • Channels take an optional capacity parameter • Allow senders to send multiple elements before suspending
  • 96. @manuelvicnt #DroidconBos B U F F E R E D C H A N N E L S • Channels take an optional capacity parameter • Allow senders to send multiple elements before suspending val channel = Channel<Int>(3)
  • 97. @manuelvicnt #DroidconBos C H A N N E L S • We can also use produce that implements the ReceiveChannel interface • Only the code inside produce can send elements to the channel • Useful to create custom operators
  • 98. @manuelvicnt #DroidconBos C H A N N E L S • We can also use produce that implements the ReceiveChannel interface • Only the code inside produce can send elements to the channel • Useful to create custom operators val publisher = produce(capacity = 2) { for (x in 1..5) send(x) }
  • 99. @manuelvicnt #DroidconBos C H A N N E L S val publisher = produce(capacity = 2) { for (x in 1..5) send(x) }
  • 100. @manuelvicnt #DroidconBos C H A N N E L S val publisher = produce(capacity = 2) { for (x in 1..5) send(x) } launch { publisher.consumeEach { consumeValue(it) } }
  • 101. @manuelvicnt #DroidconBos R A C E C O N D I T I O N I N C H A N N E L S val channel = Channel<Int>()
  • 102. @manuelvicnt #DroidconBos R A C E C O N D I T I O N I N C H A N N E L S launch { val value1 = channel.receive() } launch { val value2 = channel.receive() } val channel = Channel<Int>()
  • 103. @manuelvicnt #DroidconBos R A C E C O N D I T I O N I N C H A N N E L S launch { val value1 = channel.receive() } launch { val value2 = channel.receive() } val channel = Channel<Int>() launch { channel.send(1) }
  • 104. B R O A D C A S T C H A N N E L
  • 105. @manuelvicnt #DroidconBos B R O A D C A S T C H A N N E L • Similar to RxJava Subjects • Rx Hot Observable behavior
  • 106. @manuelvicnt #DroidconBos B R O A D C A S T C H A N N E L • Similar to RxJava Subjects • Rx Hot Observable behavior publishSubject.subscribe { consumeValue(it) } publishSubject.subscribe { println(it) } Observer 1 Timeline Observer 2 Timeline
  • 107. @manuelvicnt #DroidconBos B R O A D C A S T C H A N N E L • Similar to RxJava Subjects • Rx Hot Observable behavior publishSubject.subscribe { consumeValue(it) } publishSubject.subscribe { println(it) } publishSubject.onNext(3) Observer 1 Timeline Observer 2 Timeline
  • 108. @manuelvicnt #DroidconBos B R O A D C A S T C H A N N E L • Similar to RxJava Subjects • Rx Hot Observable behavior publishSubject.subscribe { consumeValue(it) } publishSubject.subscribe { println(it) } publishSubject.onNext(3) Observer 1 Timeline Observer 2 Timeline 3 3
  • 109. @manuelvicnt #DroidconBos B R O A D C A S T C H A N N E L • BroadcastChannel implements the SendChannel<E> interface • Emit the same item to multiple consumers that listen for the elements using openSubscription() val channel = BroadcastChannel<Int>(2)
  • 110. @manuelvicnt #DroidconBos B R O A D C A S T C H A N N E L val channel = BroadcastChannel<Int>(2) val observer1Job = launch { channel.openSubscription().use { channel -> for (value in channel) { consumeValue(value) } } }
  • 111. @manuelvicnt #DroidconBos B R O A D C A S T C H A N N E L Observer 1 Timeline val channel = BroadcastChannel<Int>(2) val observer1Job = launch { channel.openSubscription().use { channel -> for (value in channel) { consumeValue(value) } } }
  • 112. @manuelvicnt #DroidconBos B R O A D C A S T C H A N N E L val observer2Job = launch { channel.consumeEach { value -> consumeValue(value) } }
  • 113. @manuelvicnt #DroidconBos B R O A D C A S T C H A N N E L val observer2Job = launch { channel.consumeEach { value -> consumeValue(value) } } Observer 2 Timeline
  • 114. @manuelvicnt #DroidconBos B R O A D C A S T C H A N N E L Observer 2 Timeline Observer 1 Timeline Channel Capacity 2
  • 115. @manuelvicnt #DroidconBos B R O A D C A S T C H A N N E L Observer 2 Timeline Observer 1 Timeline Channel Capacity 2
  • 116. @manuelvicnt #DroidconBos B R O A D C A S T C H A N N E L Observer 2 Timeline Observer 1 Timeline channel.send(4) Channel Capacity 1
  • 117. @manuelvicnt #DroidconBos B R O A D C A S T C H A N N E L Observer 2 Timeline Observer 1 Timeline channel.send(4) 4 Channel Capacity 1
  • 118. @manuelvicnt #DroidconBos B R O A D C A S T C H A N N E L Observer 2 Timeline Observer 1 Timeline channel.send(4) 4 Channel Capacity 1
  • 119. @manuelvicnt #DroidconBos B R O A D C A S T C H A N N E L Observer 2 Timeline Observer 1 Timeline channel.send(4) 4 4 Channel Capacity 2
  • 120. @manuelvicnt #DroidconBos B R O A D C A S T C H A N N E L Observer 2 Timeline Observer 1 Timeline channel.send(4) 4 4 Channel Capacity 2
  • 121. @manuelvicnt #DroidconBos B R O A D C A S T C H A N N E L Observer 2 Timeline Observer 1 Timeline channel.send(4) 4 4 channel.send(2) Channel Capacity 1
  • 122. @manuelvicnt #DroidconBos B R O A D C A S T C H A N N E L Observer 2 Timeline Observer 1 Timeline channel.send(4) 4 4 channel.send(2) 2 Channel Capacity 1
  • 123. @manuelvicnt #DroidconBos B R O A D C A S T C H A N N E L Observer 2 Timeline Observer 1 Timeline channel.send(4) 4 4 channel.send(2) 2 Channel Capacity 1
  • 124. @manuelvicnt #DroidconBos B R O A D C A S T C H A N N E L Observer 2 Timeline Observer 1 Timeline channel.send(4) 4 4 channel.send(2) 2 2 Channel Capacity 2
  • 125. @manuelvicnt #DroidconBos B R O A D C A S T C H A N N E L • Special mention to ConflatedBroadcastChannel • Conflated is a special type of capacity • Behavior similar to Rx BehaviorSubject
  • 126. @manuelvicnt #DroidconBos C O N F L AT E D B R O A D C A S T C H A N N E L Observer 1 Timeline 4 2
  • 127. @manuelvicnt #DroidconBos C O N F L AT E D B R O A D C A S T C H A N N E L Observer 1 Timeline 4 2 // Closes Subscription
  • 128. @manuelvicnt #DroidconBos C O N F L AT E D B R O A D C A S T C H A N N E L Observer 1 Timeline 4 2 // Closes Subscription // Resubscribes to ConflatedBroadcastChannel
  • 129. @manuelvicnt #DroidconBos C O N F L AT E D B R O A D C A S T C H A N N E L Observer 1 Timeline 4 2 // Closes Subscription // Resubscribes to ConflatedBroadcastChannel New Observer 1 Timeline 2
  • 130. @manuelvicnt #DroidconBos It’s supported by default What about Rx back-pressure?
  • 131. @manuelvicnt #DroidconBos Observable Channel Subject Broadcast Channel Cold Hot Hot Hot Unicast Unicast Broadcast Broadcast C O M PA R I S O N
  • 132. @manuelvicnt #DroidconBos C H A N N E L S • If we want a “Cold Observable” behavior, we can use publish
  • 133. @manuelvicnt #DroidconBos C H A N N E L S • If we want a “Cold Observable” behavior, we can use publish val publisher = publish { for (x in 1..5) send(x) }
  • 134. @manuelvicnt #DroidconBos C H A N N E L S • If we want a “Cold Observable” behavior, we can use publish val publisher = publish { for (x in 1..5) send(x) } publisher.openSubscription().use { channel -> for (value in channel) { consumeValue(value) } }
  • 135. I N T E R O P org.jetbrains.kotlinx:kotlinx-coroutines-rx2:$kotlin_coroutines_version
  • 136. @manuelvicnt #DroidconBos R X J AVA - > C O R O U T I N E S • OpenSubscription Observable.interval( 1, TimeUnit.SECONDS ) .openSubscription().use { channel -> for (value in channel) { consumeValue(value) } }
  • 137. @manuelvicnt #DroidconBos R X J AVA - > C O R O U T I N E S • OpenSubscription Observable.interval( 1, TimeUnit.SECONDS ) .openSubscription().use { channel -> for (value in channel) { consumeValue(value) } }
  • 138. @manuelvicnt #DroidconBos R X J AVA - > C O R O U T I N E S • OpenSubscription Observable.interval( 1, TimeUnit.SECONDS ) .openSubscription().use { channel -> for (value in channel) { consumeValue(value) } }
  • 139. @manuelvicnt #DroidconBos R X J AVA - > C O R O U T I N E S • Await
  • 140. @manuelvicnt #DroidconBos R X J AVA - > C O R O U T I N E S • Await val value = Observable.interval( 1, TimeUnit.SECONDS ) .awaitFirstOrDefault(-1)
  • 141. @manuelvicnt #DroidconBos R X J AVA - > C O R O U T I N E S • Await val value = Observable.interval( 1, TimeUnit.SECONDS ) .awaitFirstOrDefault(-1)
  • 142. @manuelvicnt #DroidconBos C O R O U T I N E S - > R X J AVA • Job.asCompletable
  • 143. @manuelvicnt #DroidconBos C O R O U T I N E S - > R X J AVA • Job.asCompletable val job = launch { heavyComputation() } job.asCompletable(CommonPool).subscribe({ // Job completed })
  • 144. @manuelvicnt #DroidconBos C O R O U T I N E S - > R X J AVA • Job.asCompletable val job = launch { heavyComputation() } job.asCompletable(CommonPool).subscribe({ // Job completed })
  • 145. @manuelvicnt #DroidconBos C O R O U T I N E S - > R X J AVA • Job.asCompletable val job = launch { heavyComputation() } job.asCompletable(CommonPool).subscribe({ // Job completed })
  • 146. @manuelvicnt #DroidconBos C O R O U T I N E S - > R X J AVA • Deferred.asSingle val deferred = async { heavyComputation() } deferred.asSingle(CommonPool).subscribe({ // Job completed }, { // Error happened })
  • 147. @manuelvicnt #DroidconBos C O R O U T I N E S - > R X J AVA • Deferred.asSingle val deferred = async { heavyComputation() } deferred.asSingle(CommonPool).subscribe({ // Job completed }, { // Error happened })
  • 148. @manuelvicnt #DroidconBos C O R O U T I N E S - > R X J AVA • Deferred.asSingle val deferred = async { heavyComputation() } deferred.asSingle(CommonPool).subscribe({ // Job completed }, { // Error happened })
  • 149. @manuelvicnt #DroidconBos C O R O U T I N E S - > R X J AVA • CoroutineBuilders • rxCompletable • rxMaybe • rxSingle • rxObservable • rxFlowable
  • 150. @manuelvicnt #DroidconBos C O R O U T I N E S - > R X J AVA • CoroutineBuilders • rxCompletable • rxMaybe • rxSingle • rxObservable • rxFlowable rxCompletable { // Suspending lambda }.subscribe()
  • 151. A C T O R S
  • 152. @manuelvicnt #DroidconBos A C T O R S • Actor = Coroutine + Channel • Opposite of produce
  • 153. @manuelvicnt #DroidconBos A C T O R S • Actor = Coroutine + Channel • Opposite of produce val actor = actor<Int>() { for (int in channel) { // iterate over received Integers } }
  • 154. @manuelvicnt #DroidconBos A C T O R S • Actor = Coroutine + Channel • Opposite of produce val actor = actor<Int>() { for (int in channel) { // iterate over received Integers } } launch { actor.send(2) }
  • 155. @manuelvicnt #DroidconBos A C T O R S val userActionActor = actor<MainUserAction>(CommonPool) { for (msg in channel) { // iterate over incoming messages when (msg) { is MainUserAction.FirstAction -> { // Do something } is MainUserAction.SecondAction -> { // Do something } } } }
  • 156. @manuelvicnt #DroidconBos A C T O R S val userActionActor = actor<MainUserAction>(CommonPool) { for (msg in channel) { // iterate over incoming messages when (msg) { is MainUserAction.FirstAction -> { // Do something } is MainUserAction.SecondAction -> { // Do something } } } }
  • 157. @manuelvicnt #DroidconBos A C T O R S val userActionActor = actor<MainUserAction>(CommonPool) { for (msg in channel) { // iterate over incoming messages when (msg) { is MainUserAction.FirstAction -> { // Do something } is MainUserAction.SecondAction -> { // Do something } } } }
  • 158. @manuelvicnt #DroidconBos A C T O R S val userActionActor = actor<MainUserAction>(CommonPool) { for (msg in channel) { when (msg) { is MainUserAction.FirstAction -> { // Do something } is MainUserAction.SecondAction -> { // Do something } } } }
  • 159. O P E R AT O R S
  • 160. @manuelvicnt #DroidconBos O P E R AT O R S • Some operators are built into the language with Kotlin Collections RxJava Coroutines map map filter filter skip drop reduce reduce
  • 161. @manuelvicnt #DroidconBos O P E R AT O R S • Some others are easy to implement fun range( context: CoroutineContext, start: Int, count: Int ) = publish(context) { for (x in start until start + count) send(x) }
  • 162. @manuelvicnt #DroidconBos O P E R AT O R S • Some others require more work • Completable.zip suspend fun zip(block: () -> Unit, block2: () -> Unit) { val deferred1 = async { block() } val deferred2 = async { block2() } deferred1.await() deferred2.await() }
  • 163. @manuelvicnt #DroidconBos C O M P L E X O P E R AT O R S RxJava Coroutines timeout withTimeoutOrNull retry repeat(times) debounce ReceiveChannel<T>.debounce() groupBy groupBy
  • 164. T H R E A D I N G
  • 165. @manuelvicnt #DroidconBos T H R E A D I N G I N R X
  • 166. @manuelvicnt #DroidconBos T H R E A D I N G I N R X • Threading control Operators: observeOn and subscribeOn
  • 167. @manuelvicnt #DroidconBos T H R E A D I N G I N R X • Threading control Operators: observeOn and subscribeOn • Scheduler is a tool that schedules actions to be performed
  • 168. @manuelvicnt #DroidconBos T H R E A D I N G I N R X • Threading control Operators: observeOn and subscribeOn • Scheduler is a tool that schedules actions to be performed • You can create your own Scheduler
  • 169. @manuelvicnt #DroidconBos T H R E A D I N G Single.zip( Single.just(3), Single.just(4), BiFunction<Int, Int, Int> { n1, n2 -> n1 + n2 } ) .subscribeOn(Schedulers.computation()) .observeOn(Schedulers.io()) .flatMap { n -> Single.just(n * n) } .observeOn(Schedulers.computation()) .flatMap { n -> Single.just(n - 1) } .observeOn(AndroidSchedulers.mainThread()) .subscribe({ println("Finished with result $it") }, { println("Failed with error $it") })
  • 170. @manuelvicnt #DroidconBos T H R E A D I N G Single.zip( Single.just(3), Single.just(4), BiFunction<Int, Int, Int> { n1, n2 -> n1 + n2 } ) .subscribeOn(Schedulers.computation()) .observeOn(Schedulers.io()) .flatMap { n -> Single.just(n * n) } .observeOn(Schedulers.computation()) .flatMap { n -> Single.just(n - 1) } .observeOn(AndroidSchedulers.mainThread()) .subscribe({ println("Finished with result $it") }, { println("Failed with error $it") })
  • 171. @manuelvicnt #DroidconBos T H R E A D I N G Single.zip( Single.just(3), Single.just(4), BiFunction<Int, Int, Int> { n1, n2 -> n1 + n2 } ) .subscribeOn(Schedulers.computation()) .observeOn(Schedulers.io()) .flatMap { n -> Single.just(n * n) } .observeOn(Schedulers.computation()) .flatMap { n -> Single.just(n - 1) } .observeOn(AndroidSchedulers.mainThread()) .subscribe({ println("Finished with result $it") }, { println("Failed with error $it") })
  • 172. @manuelvicnt #DroidconBos T H R E A D I N G Single.zip( Single.just(3), Single.just(4), BiFunction<Int, Int, Int> { n1, n2 -> n1 + n2 } ) .subscribeOn(Schedulers.computation()) .observeOn(Schedulers.io()) .flatMap { n -> Single.just(n * n) } .observeOn(Schedulers.computation()) .flatMap { n -> Single.just(n - 1) } .observeOn(AndroidSchedulers.mainThread()) .subscribe({ println("Finished with result $it") }, { println("Failed with error $it") }) Computation
  • 173. @manuelvicnt #DroidconBos T H R E A D I N G Single.zip( Single.just(3), Single.just(4), BiFunction<Int, Int, Int> { n1, n2 -> n1 + n2 } ) .subscribeOn(Schedulers.computation()) .observeOn(Schedulers.io()) .flatMap { n -> Single.just(n * n) } .observeOn(Schedulers.computation()) .flatMap { n -> Single.just(n - 1) } .observeOn(AndroidSchedulers.mainThread()) .subscribe({ println("Finished with result $it") }, { println("Failed with error $it") })
  • 174. @manuelvicnt #DroidconBos T H R E A D I N G Single.zip( Single.just(3), Single.just(4), BiFunction<Int, Int, Int> { n1, n2 -> n1 + n2 } ) .subscribeOn(Schedulers.computation()) .observeOn(Schedulers.io()) .flatMap { n -> Single.just(n * n) } .observeOn(Schedulers.computation()) .flatMap { n -> Single.just(n - 1) } .observeOn(AndroidSchedulers.mainThread()) .subscribe({ println("Finished with result $it") }, { println("Failed with error $it") }) Computation
  • 175. @manuelvicnt #DroidconBos T H R E A D I N G Single.zip( Single.just(3), Single.just(4), BiFunction<Int, Int, Int> { n1, n2 -> n1 + n2 } ) .subscribeOn(Schedulers.computation()) .observeOn(Schedulers.io()) .flatMap { n -> Single.just(n * n) } .observeOn(Schedulers.computation()) .flatMap { n -> Single.just(n - 1) } .observeOn(AndroidSchedulers.mainThread()) .subscribe({ println("Finished with result $it") }, { println("Failed with error $it") }) Computation
  • 176. @manuelvicnt #DroidconBos T H R E A D I N G Single.zip( Single.just(3), Single.just(4), BiFunction<Int, Int, Int> { n1, n2 -> n1 + n2 } ) .subscribeOn(Schedulers.computation()) .observeOn(Schedulers.io()) .flatMap { n -> Single.just(n * n) } .observeOn(Schedulers.computation()) .flatMap { n -> Single.just(n - 1) } .observeOn(AndroidSchedulers.mainThread()) .subscribe({ println("Finished with result $it") }, { println("Failed with error $it") }) Computation Io
  • 177. @manuelvicnt #DroidconBos T H R E A D I N G Single.zip( Single.just(3), Single.just(4), BiFunction<Int, Int, Int> { n1, n2 -> n1 + n2 } ) .subscribeOn(Schedulers.computation()) .observeOn(Schedulers.io()) .flatMap { n -> Single.just(n * n) } .observeOn(Schedulers.computation()) .flatMap { n -> Single.just(n - 1) } .observeOn(AndroidSchedulers.mainThread()) .subscribe({ println("Finished with result $it") }, { println("Failed with error $it") }) Computation Io
  • 178. @manuelvicnt #DroidconBos T H R E A D I N G Single.zip( Single.just(3), Single.just(4), BiFunction<Int, Int, Int> { n1, n2 -> n1 + n2 } ) .subscribeOn(Schedulers.computation()) .observeOn(Schedulers.io()) .flatMap { n -> Single.just(n * n) } .observeOn(Schedulers.computation()) .flatMap { n -> Single.just(n - 1) } .observeOn(AndroidSchedulers.mainThread()) .subscribe({ println("Finished with result $it") }, { println("Failed with error $it") }) Computation Io
  • 179. @manuelvicnt #DroidconBos T H R E A D I N G Single.zip( Single.just(3), Single.just(4), BiFunction<Int, Int, Int> { n1, n2 -> n1 + n2 } ) .subscribeOn(Schedulers.computation()) .observeOn(Schedulers.io()) .flatMap { n -> Single.just(n * n) } .observeOn(Schedulers.computation()) .flatMap { n -> Single.just(n - 1) } .observeOn(AndroidSchedulers.mainThread()) .subscribe({ println("Finished with result $it") }, { println("Failed with error $it") }) Computation Io
  • 180. @manuelvicnt #DroidconBos T H R E A D I N G Single.zip( Single.just(3), Single.just(4), BiFunction<Int, Int, Int> { n1, n2 -> n1 + n2 } ) .subscribeOn(Schedulers.computation()) .observeOn(Schedulers.io()) .flatMap { n -> Single.just(n * n) } .observeOn(Schedulers.computation()) .flatMap { n -> Single.just(n - 1) } .observeOn(AndroidSchedulers.mainThread()) .subscribe({ println("Finished with result $it") }, { println("Failed with error $it") }) Computation Io Main Thread
  • 181. @manuelvicnt #DroidconBos T H R E A D I N G I N C O R O U T I N E S
  • 182. @manuelvicnt #DroidconBos T H R E A D I N G I N C O R O U T I N E S • It is defined in the CoroutineContext with a value for the key ContinuationInterceptor
  • 183. @manuelvicnt #DroidconBos T H R E A D I N G I N C O R O U T I N E S • It is defined in the CoroutineContext with a value for the key ContinuationInterceptor • Specified with a CoroutineDispatcher • Specific Thread • Thread Pool
  • 184. @manuelvicnt #DroidconBos T H R E A D I N G I N C O R O U T I N E S • Some values: • CommonPool • UI (Android) • Unconfined
  • 185. @manuelvicnt #DroidconBos T H R E A D I N G I N C O R O U T I N E S
  • 186. @manuelvicnt #DroidconBos T H R E A D I N G I N C O R O U T I N E S • Create your own ThreadPoolDispatcher
  • 187. @manuelvicnt #DroidconBos T H R E A D I N G I N C O R O U T I N E S • Create your own ThreadPoolDispatcher • NewSingleThreadContext val coroutineDispatcher = newSingleThreadContext("Name")
  • 188. @manuelvicnt #DroidconBos T H R E A D I N G I N C O R O U T I N E S • Create your own ThreadPoolDispatcher • NewSingleThreadContext • NewFixedThreadPoolContext ••val coroutineDispatcher = newFixedThreadPoolContext(4, "Name") val coroutineDispatcher = newSingleThreadContext("Name")
  • 189. @manuelvicnt #DroidconBos T H R E A D I N G launch(CommonPool) { val deferred1 = async(coroutineContext) { 3 } val deferred2 = async(coroutineContext) { 4 } var result = deferred1.await() + deferred2.await() launch(newSingleThreadContext("CustomThread")) { result = result * result - 1 }.join() withContext(UI) { println("Finished with result $result") } }
  • 190. @manuelvicnt #DroidconBos T H R E A D I N G launch(CommonPool) { val deferred1 = async(coroutineContext) { 3 } val deferred2 = async(coroutineContext) { 4 } var result = deferred1.await() + deferred2.await() launch(newSingleThreadContext("CustomThread")) { result = result * result - 1 }.join() withContext(UI) { println("Finished with result $result") } }
  • 191. @manuelvicnt #DroidconBos T H R E A D I N G launch(CommonPool) { val deferred1 = async(coroutineContext) { 3 } val deferred2 = async(coroutineContext) { 4 } var result = deferred1.await() + deferred2.await() launch(newSingleThreadContext("CustomThread")) { result = result * result - 1 }.join() withContext(UI) { println("Finished with result $result") } }
  • 192. @manuelvicnt #DroidconBos T H R E A D I N G launch(CommonPool) { val deferred1 = async(coroutineContext) { 3 } val deferred2 = async(coroutineContext) { 4 } var result = deferred1.await() + deferred2.await() launch(newSingleThreadContext("CustomThread")) { result = result * result - 1 }.join() withContext(UI) { println("Finished with result $result") } } CommonPool
  • 193. @manuelvicnt #DroidconBos T H R E A D I N G launch(CommonPool) { val deferred1 = async(coroutineContext) { 3 } val deferred2 = async(coroutineContext) { 4 } var result = deferred1.await() + deferred2.await() launch(newSingleThreadContext("CustomThread")) { result = result * result - 1 }.join() withContext(UI) { println("Finished with result $result") } } CommonPool
  • 194. @manuelvicnt #DroidconBos T H R E A D I N G launch(CommonPool) { val deferred1 = async(coroutineContext) { 3 } val deferred2 = async(coroutineContext) { 4 } var result = deferred1.await() + deferred2.await() launch(newSingleThreadContext("CustomThread")) { result = result * result - 1 }.join() withContext(UI) { println("Finished with result $result") } } CommonPool CustomThread
  • 195. @manuelvicnt #DroidconBos T H R E A D I N G launch(CommonPool) { val deferred1 = async(coroutineContext) { 3 } val deferred2 = async(coroutineContext) { 4 } var result = deferred1.await() + deferred2.await() launch(newSingleThreadContext("CustomThread")) { result = result * result - 1 }.join() withContext(UI) { println("Finished with result $result") } } CommonPool CustomThread
  • 196. @manuelvicnt #DroidconBos T H R E A D I N G launch(CommonPool) { val deferred1 = async(coroutineContext) { 3 } val deferred2 = async(coroutineContext) { 4 } var result = deferred1.await() + deferred2.await() launch(newSingleThreadContext("CustomThread")) { result = result * result - 1 }.join() withContext(UI) { println("Finished with result $result") } } CommonPool CustomThread UI
  • 197. M AT H A P P M V I A R C H I T E C T U R E
  • 199. @manuelvicnt #DroidconBos M AT H A P P • Three Projects. Implemented with: • Coroutines • RxJava • Coroutines/RxJava Interop
  • 200. @manuelvicnt #DroidconBos M AT H A P P • MVI • Architecture Components ViewModels • Survives Configuration Changes
  • 201. R E S T O R E S TAT E
  • 202. @manuelvicnt #DroidconBos M V I A R C H I T E C T U R E V I E W V I E W M O D E L 1. User Input 2. User Action 3. Process Result4. View State 5. Render State
  • 203. @manuelvicnt #DroidconBos M V I A R C H I T E C T U R E V I E W V I E W M O D E L 1. User Input 2. User Action 3. Process Result4. View State 5. Render State ?
  • 204. @manuelvicnt #DroidconBos M V I A R C H I T E C T U R E V I E W V I E W M O D E L 1. User Input 2. User Action 3. Process Result4. View State 5. Render State ? ?
  • 205. @manuelvicnt #DroidconBos R X A R C H I T E C T U R E V I E W V I E W M O D E L 1. User Input 2. User Action S U B J E C T * S U B J E C T * 3. Process Result4. View State 5. Render State * Not optimal
  • 206. @manuelvicnt #DroidconBos R X A R C H I T E C T U R E V I E W V I E W M O D E L 2. User Action R X R E L AY O B S E R VA B L E 4. View State Exposes an Observable but implemented with a Subject so View cannot call onNext() RxRelay to avoid the View calling onComplete()
  • 207. @manuelvicnt #DroidconBos C O R O U T I N E S A R C H I T E C T U R E V I E W V I E W M O D E L 1. User Input 2. User Action A C T O R C B C * * ConflatedBroadcastChannel 3. Process Result4. View State 5. Render State
  • 208. @manuelvicnt #DroidconBos C O M M O N I M P L E M E N TAT I O N sealed class MainUserAction { class Calculate( val number: Long ) : MainUserAction() class FunFactEnabled( val enabled: Boolean ) : MainUserAction() }
  • 209. @manuelvicnt #DroidconBos C O M M O N I M P L E M E N TAT I O N sealed class MainViewState { object Loading : MainViewState() class Rendered( val fibonacciNumber: Long, val funFact: String ) : MainViewState() object WrongInputError : MainViewState() object RequestError : MainViewState() }
  • 210. @manuelvicnt #DroidconBos V I E W M O D E L • Extends from ViewModel in Architecture Components • Receives User Actions • Processes User Action • Notifies View with the ViewState
  • 211. @manuelvicnt #DroidconBos R X V I E W M O D E L
  • 212. @manuelvicnt #DroidconBos R X V I E W M O D E L • Receives User Actions val userActionSubject: PublishSubject<MainUserAction>
  • 213. @manuelvicnt #DroidconBos R X V I E W M O D E L • Receives User Actions • Notifies View with the ViewState val viewStateSubject: BehaviorSubject<MainViewState> val userActionSubject: PublishSubject<MainUserAction>
  • 214. @manuelvicnt #DroidconBos R X V I E W M O D E L init { userActionSubject .subscribeOn(Schedulers.computation()) .subscribe({ when (it) { is MainUserAction.Calculate -> { if (it.number <= 0) { viewStateSubject. onNext(MainViewState.WrongInputError) } else { viewStateSubject.onNext(MainViewState.Loading) processCalculation(it) } } is MainUserAction.FunFactEnabled -> { askForFunFact = it.enabled } } }) }
  • 215. @manuelvicnt #DroidconBos R X V I E W M O D E L init { userActionSubject .subscribeOn(Schedulers.computation()) .subscribe({ when (it) { is MainUserAction.Calculate -> { if (it.number <= 0) { viewStateSubject. onNext(MainViewState.WrongInputError) } else { viewStateSubject.onNext(MainViewState.Loading) processCalculation(it) } } is MainUserAction.FunFactEnabled -> { askForFunFact = it.enabled } } }) }
  • 216. @manuelvicnt #DroidconBos R X V I E W M O D E L init { userActionSubject .subscribeOn(Schedulers.computation()) .subscribe({ when (it) { is MainUserAction.Calculate -> { if (it.number <= 0) { viewStateSubject. onNext(MainViewState.WrongInputError) } else { viewStateSubject.onNext(MainViewState.Loading) processCalculation(it) } } is MainUserAction.FunFactEnabled -> { askForFunFact = it.enabled } } }) }
  • 217. @manuelvicnt #DroidconBos R X V I E W M O D E L init { userActionSubject .subscribeOn(Schedulers.computation()) .subscribe({ when (it) { is MainUserAction.Calculate -> { if (it.number <= 0) { viewStateSubject. onNext(MainViewState.WrongInputError) } else { viewStateSubject.onNext(MainViewState.Loading) processCalculation(it) } } is MainUserAction.FunFactEnabled -> { askForFunFact = it.enabled } } }) }
  • 218. @manuelvicnt #DroidconBos R X V I E W M O D E L init { userActionSubject .subscribeOn(Schedulers.computation()) .subscribe({ when (it) { is MainUserAction.Calculate -> { if (it.number <= 0) { viewStateSubject. onNext(MainViewState.WrongInputError) } else { viewStateSubject.onNext(MainViewState.Loading) processCalculation(it) } } is MainUserAction.FunFactEnabled -> { askForFunFact = it.enabled } } }) }
  • 219. @manuelvicnt #DroidconBos • Clean up when it’s not longer needed R X V I E W M O D E L override fun onCleared() { userActionSubject.onComplete() viewStateSubject.onComplete() super.onCleared() }
  • 220. @manuelvicnt #DroidconBos C O R O U T I N E S V I E W M O D E L
  • 221. @manuelvicnt #DroidconBos C O R O U T I N E S V I E W M O D E L • Receives User Actions val userActionActor = actor<MainUserAction>(CommonPool, parent = parentJob)
  • 222. @manuelvicnt #DroidconBos C O R O U T I N E S V I E W M O D E L • Receives User Actions • Notifies View with the ViewState val viewStateChannel = ConflatedBroadcastChannel<MainViewState>() val userActionActor = actor<MainUserAction>(CommonPool, parent = parentJob)
  • 223. @manuelvicnt #DroidconBos C O R O U T I N E S V I E W M O D E L private val parentJob = Job() val userActionActor = actor<MainUserAction>( CommonPool, parent = parentJob ) { for (msg in channel) { // iterate over incoming messages when (msg) { is MainUserAction.Calculate -> { if (msg.number <= 0) { viewStateChannel.offer(MainViewState.WrongInputError) } else { viewStateChannel.offer(MainViewState.Loading) processCalculation(msg) } } is MainUserAction.FunFactEnabled -> { askForFunFact = msg.enabled } } } }
  • 224. @manuelvicnt #DroidconBos C O R O U T I N E S V I E W M O D E L private val parentJob = Job() val userActionActor = actor<MainUserAction>( CommonPool, parent = parentJob ) { for (msg in channel) { // iterate over incoming messages when (msg) { is MainUserAction.Calculate -> { if (msg.number <= 0) { viewStateChannel.offer(MainViewState.WrongInputError) } else { viewStateChannel.offer(MainViewState.Loading) processCalculation(msg) } } is MainUserAction.FunFactEnabled -> { askForFunFact = msg.enabled } } } }
  • 225. @manuelvicnt #DroidconBos C O R O U T I N E S V I E W M O D E L private val parentJob = Job() val userActionActor = actor<MainUserAction>( CommonPool, parent = parentJob ) { for (msg in channel) { // iterate over incoming messages when (msg) { is MainUserAction.Calculate -> { if (msg.number <= 0) { viewStateChannel.offer(MainViewState.WrongInputError) } else { viewStateChannel.offer(MainViewState.Loading) processCalculation(msg) } } is MainUserAction.FunFactEnabled -> { askForFunFact = msg.enabled } } } }
  • 226. @manuelvicnt #DroidconBos C O R O U T I N E S V I E W M O D E L private val parentJob = Job() val userActionActor = actor<MainUserAction>( CommonPool, parent = parentJob ) { for (msg in channel) { // iterate over incoming messages when (msg) { is MainUserAction.Calculate -> { if (msg.number <= 0) { viewStateChannel.offer(MainViewState.WrongInputError) } else { viewStateChannel.offer(MainViewState.Loading) processCalculation(msg) } } is MainUserAction.FunFactEnabled -> { askForFunFact = msg.enabled } } } }
  • 227. @manuelvicnt #DroidconBos C O R O U T I N E S V I E W M O D E L private val parentJob = Job() val userActionActor = actor<MainUserAction>( CommonPool, parent = parentJob ) { for (msg in channel) { // iterate over incoming messages when (msg) { is MainUserAction.Calculate -> { if (msg.number <= 0) { viewStateChannel.offer(MainViewState.WrongInputError) } else { viewStateChannel.offer(MainViewState.Loading) processCalculation(msg) } } is MainUserAction.FunFactEnabled -> { askForFunFact = msg.enabled } } } }
  • 228. @manuelvicnt #DroidconBos • Clean up when it’s not longer needed C O R O U T I N E S V I E W M O D E L override fun onCleared() { viewStateChannel.close() parentJob.cancel() // Cancels the Actor super.onCleared() }
  • 229. @manuelvicnt #DroidconBos V I E W • Listens for User Events • Talks to ViewModel to process Input • Renders ViewState
  • 230. @manuelvicnt #DroidconBos R X J AVA V I E W • Listens for User Events • Talks to ViewModel to process Input private fun setupViews() { calcButton.setOnClickListener { viewModel.userActionSubject.onNext( MainUserAction.Calculate( input.text.toString().toLong())) } funFact.setOnCheckedChangeListener { _, isChecked -> viewModel.userActionSubject.onNext( MainUserAction.FunFactEnabled(isChecked)) } }
  • 231. @manuelvicnt #DroidconBos R X J AVA V I E W • Listens for User Events • Talks to ViewModel to process Input private fun setupViews() { calcButton.setOnClickListener { viewModel.userActionSubject.onNext( MainUserAction.Calculate( input.text.toString().toLong())) } funFact.setOnCheckedChangeListener { _, isChecked -> viewModel.userActionSubject.onNext( MainUserAction.FunFactEnabled(isChecked)) } }
  • 232. @manuelvicnt #DroidconBos R X J AVA V I E W • Listens for User Events • Talks to ViewModel to process Input private fun setupViews() { calcButton.setOnClickListener { viewModel.userActionSubject.onNext( MainUserAction.Calculate( input.text.toString().toLong())) } funFact.setOnCheckedChangeListener { _, isChecked -> viewModel.userActionSubject.onNext( MainUserAction.FunFactEnabled(isChecked)) } }
  • 233. @manuelvicnt #DroidconBos R X J AVA V I E W private fun listenViewModel() { viewStateDisposable = viewModel.viewStateObservable .observeOn(AndroidSchedulers.mainThread()) .subscribe({ when (it) { MainViewState.Loading -> { progressBar.visibility = View.VISIBLE result.text = "Loading..." funFactText.text = "" } MainViewState.WrongInputError -> { showError() } … } }) }
  • 234. @manuelvicnt #DroidconBos R X J AVA V I E W • Renders ViewState private fun listenViewModel() { viewStateDisposable = viewModel.viewStateObservable .observeOn(AndroidSchedulers.mainThread()) .subscribe({ when (it) { MainViewState.Loading -> { progressBar.visibility = View.VISIBLE result.text = "Loading..." funFactText.text = "" } MainViewState.WrongInputError -> { showError() } … } }) }
  • 235. @manuelvicnt #DroidconBos R X J AVA V I E W private fun listenViewModel() { viewStateDisposable = viewModel.viewStateObservable .observeOn(AndroidSchedulers.mainThread()) .subscribe({ when (it) { MainViewState.Loading -> { progressBar.visibility = View.VISIBLE result.text = "Loading..." funFactText.text = "" } MainViewState.WrongInputError -> { showError() } … } }) }
  • 236. @manuelvicnt #DroidconBos R X J AVA V I E W • Renders ViewState private fun listenViewModel() { viewStateDisposable = viewModel.viewStateObservable .observeOn(AndroidSchedulers.mainThread()) .subscribe({ when (it) { MainViewState.Loading -> { progressBar.visibility = View.VISIBLE result.text = "Loading..." funFactText.text = "" } MainViewState.WrongInputError -> { showError() } … } }) }
  • 237. @manuelvicnt #DroidconBos R X J AVA V I E W private fun listenViewModel() { viewStateDisposable = viewModel.viewStateObservable .observeOn(AndroidSchedulers.mainThread()) .subscribe({ when (it) { MainViewState.Loading -> { progressBar.visibility = View.VISIBLE result.text = "Loading..." funFactText.text = "" } MainViewState.WrongInputError -> { showError() } … } }) }
  • 238. @manuelvicnt #DroidconBos R X J AVA V I E W • Renders ViewState private fun listenViewModel() { viewStateDisposable = viewModel.viewStateObservable .observeOn(AndroidSchedulers.mainThread()) .subscribe({ when (it) { MainViewState.Loading -> { progressBar.visibility = View.VISIBLE result.text = "Loading..." funFactText.text = "" } MainViewState.WrongInputError -> { showError() } … } }) }
  • 239. @manuelvicnt #DroidconBos R X J AVA V I E W override fun onStart() { super.onStart() listenViewModel() // Registers to ViewState Observable } override fun onStop() { if (viewStateDisposable?.isDisposed == false) { viewStateDisposable?.dispose() } super.onStop() }
  • 240. @manuelvicnt #DroidconBos R X J AVA V I E W • View Lifecycle override fun onStart() { super.onStart() listenViewModel() // Registers to ViewState Observable } override fun onStop() { if (viewStateDisposable?.isDisposed == false) { viewStateDisposable?.dispose() } super.onStop() }
  • 241. @manuelvicnt #DroidconBos C O R O U T I N E S V I E W • Listens for User Events • Talks to ViewModel to process Input private fun setupViews() { calcButton.setOnClickListener { viewModel.userActionActor.offer( MainUserAction.Calculate( input.text.toString().toLong())) } funFact.setOnCheckedChangeListener { _, isChecked -> viewModel.userActionActor.offer( MainUserAction.FunFactEnabled(isChecked)) } }
  • 242. @manuelvicnt #DroidconBos C O R O U T I N E S V I E W • Listens for User Events • Talks to ViewModel to process Input private fun setupViews() { calcButton.setOnClickListener { viewModel.userActionActor.offer( MainUserAction.Calculate( input.text.toString().toLong())) } funFact.setOnCheckedChangeListener { _, isChecked -> viewModel.userActionActor.offer( MainUserAction.FunFactEnabled(isChecked)) } }
  • 243. @manuelvicnt #DroidconBos C O R O U T I N E S V I E W • Listens for User Events • Talks to ViewModel to process Input private fun setupViews() { calcButton.setOnClickListener { viewModel.userActionActor.offer( MainUserAction.Calculate( input.text.toString().toLong())) } funFact.setOnCheckedChangeListener { _, isChecked -> viewModel.userActionActor.offer( MainUserAction.FunFactEnabled(isChecked)) } }
  • 244. @manuelvicnt #DroidconBos C O R O U T I N E S V I E W private val parentJob = Job() private fun listenViewModel() { // Launch on the CommonPool to not block the MainThread launch(parentJob + CommonPool) { viewModel.viewStateChannel.consumeEach { withContext(UI) { when (it) { MainViewState.Loading -> { progressBar.visibility = View.VISIBLE result.text = "Loading..." funFactText.text = "" } … } } } } }
  • 245. @manuelvicnt #DroidconBos C O R O U T I N E S V I E W • Renders ViewState private val parentJob = Job() private fun listenViewModel() { // Launch on the CommonPool to not block the MainThread launch(parentJob + CommonPool) { viewModel.viewStateChannel.consumeEach { withContext(UI) { when (it) { MainViewState.Loading -> { progressBar.visibility = View.VISIBLE result.text = "Loading..." funFactText.text = "" } … } } } } }
  • 246. @manuelvicnt #DroidconBos C O R O U T I N E S V I E W private val parentJob = Job() private fun listenViewModel() { // Launch on the CommonPool to not block the MainThread launch(parentJob + CommonPool) { viewModel.viewStateChannel.consumeEach { withContext(UI) { when (it) { MainViewState.Loading -> { progressBar.visibility = View.VISIBLE result.text = "Loading..." funFactText.text = "" } … } } } } }
  • 247. @manuelvicnt #DroidconBos C O R O U T I N E S V I E W • Renders ViewState private val parentJob = Job() private fun listenViewModel() { // Launch on the CommonPool to not block the MainThread launch(parentJob + CommonPool) { viewModel.viewStateChannel.consumeEach { withContext(UI) { when (it) { MainViewState.Loading -> { progressBar.visibility = View.VISIBLE result.text = "Loading..." funFactText.text = "" } … } } } } }
  • 248. @manuelvicnt #DroidconBos C O R O U T I N E S V I E W private val parentJob = Job() private fun listenViewModel() { // Launch on the CommonPool to not block the MainThread launch(parentJob + CommonPool) { viewModel.viewStateChannel.consumeEach { withContext(UI) { when (it) { MainViewState.Loading -> { progressBar.visibility = View.VISIBLE result.text = "Loading..." funFactText.text = "" } … } } } } }
  • 249. @manuelvicnt #DroidconBos C O R O U T I N E S V I E W • Renders ViewState private val parentJob = Job() private fun listenViewModel() { // Launch on the CommonPool to not block the MainThread launch(parentJob + CommonPool) { viewModel.viewStateChannel.consumeEach { withContext(UI) { when (it) { MainViewState.Loading -> { progressBar.visibility = View.VISIBLE result.text = "Loading..." funFactText.text = "" } … } } } } }
  • 250. @manuelvicnt #DroidconBos C O R O U T I N E S V I E W private val parentJob = Job() private fun listenViewModel() { // Launch on the CommonPool to not block the MainThread launch(parentJob + CommonPool) { viewModel.viewStateChannel.consumeEach { withContext(UI) { when (it) { MainViewState.Loading -> { progressBar.visibility = View.VISIBLE result.text = "Loading..." funFactText.text = "" } … } } } } }
  • 251. @manuelvicnt #DroidconBos C O R O U T I N E S V I E W • Renders ViewState private val parentJob = Job() private fun listenViewModel() { // Launch on the CommonPool to not block the MainThread launch(parentJob + CommonPool) { viewModel.viewStateChannel.consumeEach { withContext(UI) { when (it) { MainViewState.Loading -> { progressBar.visibility = View.VISIBLE result.text = "Loading..." funFactText.text = "" } … } } } } }
  • 252. @manuelvicnt #DroidconBos C O R O U T I N E S V I E W override fun onStart() { super.onStart() listenViewModel() // Listens to ViewStateChannel } override fun onStop() { parentJob.cancel() super.onStop() }
  • 253. @manuelvicnt #DroidconBos C O R O U T I N E S V I E W • View Lifecycle override fun onStart() { super.onStart() listenViewModel() // Listens to ViewStateChannel } override fun onStop() { parentJob.cancel() super.onStop() }
  • 254. S H O W M E S O M E N U M B E R S
  • 255. @manuelvicnt #DroidconBos P E R F O R M A N C E
  • 256. @manuelvicnt #DroidconBos P E R F O R M A N C E • Roughly the same • Not difficult enough to compare
  • 257. @manuelvicnt #DroidconBos S I Z E Measure Coroutines RxJava Interop APK Size 2.4MB 2.9MB 3.1MB Method Count 29,131 37,271 39,590
  • 258. @manuelvicnt #DroidconBos G I T H U B L I N K S manuelvicnt/MathCoroutines Coroutines manuelvicnt/MathRxJava RxJava manuelvicnt/MathRxCoroutines Coroutines and RxJava
  • 259. @manuelvicnt #DroidconBos C O N C L U S I O N
  • 260. @manuelvicnt #DroidconBos C O N C L U S I O N • Both libraries provide a way to do Asynchronous Programming • If you are a RxJava expert, no need to switch • If you struggle with RxJava, Coroutines is another option you can try • For new Android developers, Coroutines has a lower learning curve
  • 261. C O R O U T I N E S A N D R X J AVA A N A S Y N C H R O N I C I T Y C O M PA R I S O N @ M A N U E LV I C N T A N Y Q U E S T I O N S ? M A N U E L V I C E N T E V I V O