Android Overview
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This document provides an overview of the Android mobile operating system. It describes Android as an open-source operating system based on a modified Linux kernel. Developers write Android apps using Java and Google's Java libraries. The document outlines Android's architecture, including the Dalvik virtual machine and distribution through app stores like Google Play. It also summarizes the main Android development tools like the SDK, Android Studio IDE, and commands for creating and building basic Android projects from the command line.
![Dalvik
VM
• Dalvik
VM
is
a
so]ware
that
runs
the
apps
on
android
devices
– Dalvik
can
be
found
on
phones,
tablets,
TVs
• Not
Java
VM!
– Designed
for
slow
CPUs
and
liUle
RAM
• Programs
are
wriUen
with
Java,
compiled
to
bytecode
and
then
converted
to
Dalvik
executable
files
(.dex)
– .java
-‐>
.class
-‐>
.dex
• The
.dex
files
and
resources
are
zipped
into
android
packages
(.apk)
– *.dex
-‐>
myapp.apk](https://image.slidesharecdn.com/android-overview-pptx-100316054510-phpapp02/85/Android-Overview-6-320.jpg)
![Google
Play
(Android
Market)
• Google
Play
is
an
online
so]ware
store
developed
by
Google
– Music,
Books,
Magazines,
Movies
and
Apps
• Preinstalled
on
some
Android
devices
• To
publish,
developer
must
pay
~16€
(Visa,
Visa
Electron)
• Developer
gets
70%
of
the
app
price
• No
human
verifica<on;
apps
are
uploaded
to
store
immediately!](https://image.slidesharecdn.com/android-overview-pptx-100316054510-phpapp02/85/Android-Overview-8-320.jpg)
![Virtual
Device
is
SLOW….
• Don't
use
virtual
device,
use
real
device
• Use
HAXM!
• Buy
SSD
• [x]
Snapshot
saves
a
snapshot
of
emulators
RAM
(hibernate)
– Speeds
up
boo<ng
• [x]
Use
Host
GPU
uses
host
computer's
graphics
card
– Speeds
up
all
graphics
opera<ons
• You
cannot
have
both
of
these
on
at
the
same
<me!](https://image.slidesharecdn.com/android-overview-pptx-100316054510-phpapp02/85/Android-Overview-18-320.jpg)
Android Overview
- 1. Android Overview Jussi Pohjolainen
- 2. What is Android? • Android is a free open source mobile opera<ng system using modified version of the Linux Kernel – Google apps are not open source (Market, Gmail, Maps) • Offers full stack: OS, middleware, apps, sdk.. • Developers write apps using Java language and Google Java libraries – OS, middleware, key mobile apps
- 3. PlaMorm Versions (Feb 24th, 2015)
- 4. Architecture WriUen in Java APIs for program mers UI elements Access data from another apps Access to non-‐ code resources Lifecycle of Apps Display alerts C Libraries Core libraries and VM Kernel
- 5. Linux Kernel on Android • Has standard Linux kernel with kernel enhancements to support Android • No standard GNU C (glibc) Library support – Uses custom libc (bionic libc) because of performance and licensing issues • No na<ve windowing system • Does not include full set of standard Linux u<li<es • To access shell, use adb shell command
- 6. Dalvik VM • Dalvik VM is a so]ware that runs the apps on android devices – Dalvik can be found on phones, tablets, TVs • Not Java VM! – Designed for slow CPUs and liUle RAM • Programs are wriUen with Java, compiled to bytecode and then converted to Dalvik executable files (.dex) – .java -‐> .class -‐> .dex • The .dex files and resources are zipped into android packages (.apk) – *.dex -‐> myapp.apk
- 7. Distribu<on • You have several op<ons for distribu<on – .apk files can be installed via memory card, web sites, e-‐mail – App stores • Several stores available – Google Play Store – Amazon App Store – GetJar App Store – Samsung Apps – ( Nokia Store )
- 8. Google Play (Android Market) • Google Play is an online so]ware store developed by Google – Music, Books, Magazines, Movies and Apps • Preinstalled on some Android devices • To publish, developer must pay ~16€ (Visa, Visa Electron) • Developer gets 70% of the app price • No human verifica<on; apps are uploaded to store immediately!
- 10. Tools • SDK Tools (Google) – Standalone command line tools for building android apps • IDE – Android Studio (Google) • This will install also SDK Tools on startup – Eclipse (requires plugin) – IntelliJ Idea
- 11. SDK tools • SDK tools are all you need • Contains all necessary command line tools for building and running your apps • When SDK tools are downloaded and installed, you must – Install Android PlaMorm – Configure emulator
- 12. SDK Tools
- 13. Command Line Tools: tools/
- 14. Command Line Tools: platform-tools/
- 15. Install PlaMorms • To install plaMorms (2.2, … 4.4), open SDK Manager • How? – android sdk • Select the plaMorms you like to install
- 16. plaMorms/
- 17. Create and Configure Emulators • To create and configure emulators (android virtual devices) – android avd • Click "New…" to create new virtual device
- 18. Virtual Device is SLOW…. • Don't use virtual device, use real device • Use HAXM! • Buy SSD • [x] Snapshot saves a snapshot of emulators RAM (hibernate) – Speeds up boo<ng • [x] Use Host GPU uses host computer's graphics card – Speeds up all graphics opera<ons • You cannot have both of these on at the same <me!
- 19. HAXM? • Download HAXM using SDK Manager • Install it • Configure your editor to use INTEL cpu • When launching the emulator you should see something like HAX is working
- 20. Genymo<on • Fast third-‐party emulator to run and test your apps • 20 pre-‐configured devices • Resizable windows • Sensor emula<on, mul<-‐touch, camera, etc. • Free for personal use
- 21. Android Studio • Installs SDK Tools – Mac: /Users/<user>/Library/Android/sdk – Win: /Users/<user>/sdk • Features – GitHub integra<on – Build apps for phones, TV, Google Glass – BeUer virtual device manager – Layout editor – Built on top of IntelliJ IDEA
- 22. CREATING ANDROID APP COMMAND LINE
- 23. Android SDK Essen<al Tools • android – To create/update Android projects and modify Android Virtual Devices • Android Emulator – To run your app • adb (Android Debug Bridge) – Interface between emulator or device. Install apps, shell the device, issue commands • Other needed tools – Ant • To compile and build your apps – Keytool and Jarsigner • To sign your .apk package
- 25. Crea<ng Project
- 26. Result
- 27. Building • Install Ant – http://ant.apache.org/bindownload.cgi • For debug: – ant debug • For release – ant release • Release version must signed using keytool and jarsigner
- 28. Building
- 29. Result
- 30. Android Virtual Devices • To run the emulator, you must configure android virtual device • To open AVD, use command android avd • Click new to create new AVD
- 32. Star<ng the Emulator • In avd, click start Or • use emulator –avd youravd command in command line
- 33. Installing App • The compiled and packaged applica<on can be found in the bin/ directory • In debug – mode, the app cannot be distributed in Google Play, but it can be installed on device or emulator • To see list of devices aUached to your computer (devices, emulators), use command – adb devices • adb? = Android Debug Bridge, command line tool for communica<ng between devices and emulators
- 35. Installing • You need to use the adb app to install the app • If you have only one device aUached, the following command is enough: – adb install HelloWorld-debug.apk • If you have several devices aUached, then you must specify the target – adb –s emulator-5554 install HelloWorld- debug.apk