Introduction to Android Development
1 like895 views
The document provides a comprehensive overview of the Android platform, detailing its architecture, supported languages, and key components necessary for building Android applications. It explains essential concepts like intents, activities, services, and the lifecycle of components within the Android framework. Additionally, it touches on development environments, security measures, and application configuration, emphasizing the unique nature of Android applications compared to web or desktop applications.
Introduction to Android Development
- 1. Presented by On Ramp Android Do Androids dream of electric sheep? Understanding the Android platform A developers perspective
- 2. 1 May 2013 Presented by On Ramp Presented by On Ramp Objective Provide a high level conceptual model for understanding how to build Android Applications
- 3. 1 May 2013 Presented by On Ramp Presented by On Ramp About Me ● South African open source solutions integrator, – Java developer, – Drupal developer, – Loves Linux, ● On Ramp – Ethiopian Company ● Linux, Java, Android training and development house ● Specialising in mobile telecoms space
- 4. 1 May 2013 Presented by On Ramp Presented by On Ramp Agenda ● Android Architecture ● Supported Languages ● Dalvik VM ● Development Environments ● Components – Building Blocks ● High Level Overview
- 5. 1 May 2013 Presented by On Ramp Presented by On Ramp Agenda ● Important concepts – Intents – Activities, Services, Content Providers & Broadcast Receivers – Resources
- 6. 1 May 2013 Presented by On Ramp Presented by On Ramp What is Android? Android is a software stack for mobile devices that includes an operating system, middleware and key applications
- 7. 1 May 2013 Presented by On Ramp Presented by On Ramp Architecture
- 8. 1 May 2013 Presented by On Ramp Presented by On Ramp Architecture ● Linux Layer – Based on Linux, – Source now part of mainline Linux V3.3 – Linux security, process management & networking
- 9. 1 May 2013 Presented by On Ramp Presented by On Ramp Architecture ● Linux Layer – Each app has its own Linux user, – All files and resources owned by app user, – Other processes, app cannot access other app's files/resources
- 10. 1 May 2013 Presented by On Ramp Presented by On Ramp Architecture ● Core libraries written in C/C++ – Android runtime – Dalvik – Services exposed via application layer, – Reuses open source components – SQLite, FreeType etc
- 11. 1 May 2013 Presented by On Ramp Presented by On Ramp Architecture ● Framework layer – What your application interacts with, – API calls to framework services, – Key concepts to grok Android API
- 12. 1 May 2013 Presented by On Ramp Presented by On Ramp Architecture YOU! â—Ź Applicationwritten to use services of the Android platform
- 13. 1 May 2013 Presented by On Ramp Presented by On Ramp Supported Languages ● Android applications can be written in – Java ● Supports a subset of Java API, ● Can use most Java libraries, – C/C++ using native development kit ● Should only be when performance is an issue.
- 14. 1 May 2013 Presented by On Ramp Presented by On Ramp Supported Languages – C/C++ using native development kit ● Used to write components called from Java
- 15. 1 May 2013 Presented by On Ramp Presented by On Ramp Supported Languages ● Second Class Citizens – Scripting languages via Scripting Layer for Android – Javascript, Ruby, Python,LUA, Perl – HTML 5 Apps ● Important – Phonegap etc
- 16. 1 May 2013 Presented by On Ramp Presented by On Ramp Dalvik ● Dalvik is a process virtual machine – Application written in Java – Complied to Java byte code (.class files) – Converted into Dalvik compatible files (.dex) when packaged
- 17. 1 May 2013 Presented by On Ramp Presented by On Ramp Dalvik ● Why Dalvik? – More compact & memory efficient than .class files – Each application runs in its own process, – Each process gets it own VM – Packaging (apk) files are zipped .dex files
- 18. 1 May 2013 Presented by On Ramp Presented by On Ramp Development Environments ● Android SDK, – Debugger ● (ADB – Andorid Debugger Bridge) – Libraries – Emulator ● Supported IDE – Eclipse – ADT plugin
- 19. 1 May 2013 Presented by On Ramp Presented by On Ramp Development Environments ● Other IDE support – NetBeans – IntelliJ – Command line/text editor ● Build tool – Ant (official)
- 20. 1 May 2013 Presented by On Ramp Presented by On Ramp Development Environments ● Build tool – Maven (support from springsource) ● Android applications have a directory structure – Naming of directories is important especially for resources
- 21. 1 May 2013 Presented by On Ramp Presented by On Ramp Core Components● Activities – UI Layer – Similar to UI controller for web apps ● Services – Provides services to other applications, no ui, run in background ● Content Providers – Used to pass information between applications ● Broadcast receivers – Listen to system events and broad cast and react
- 22. 1 May 2013 Presented by On Ramp Presented by On Ramp Core Components ● Notifications – System notifications
- 23. 1 May 2013 Presented by On Ramp Presented by On Ramp High Level Overview ● Different from web or desktop applications, ● Android in control of/manages application, – Constrained environment, – Memory management, – Power usage etc
- 24. 1 May 2013 Presented by On Ramp Presented by On Ramp High Level Overview â—Ź Components interact with one another indirectly. â—Ź Android controls creation, life cycle of components
- 25. 1 May 2013 Presented by On Ramp Presented by On Ramp High Level Understanding ● Applications can use components from other apps, ● Task Stack - – Android places UI components (Activities), maybe from different apps, onto a task stack, as user navigates through an application
- 26. 1 May 2013 Presented by On Ramp Presented by On Ramp High Level Overview ● Component life cycle controlled by platform, ● Platform provides life cycle methods to allow components to react to changes in life cycle – onStart – onResume – onPause etc
- 27. 1 May 2013 Presented by On Ramp Presented by On Ramp High Level Overview â—Ź Activity 2 & Activity 3 may be from different applications Task Stack
- 28. 1 May 2013 Presented by On Ramp Presented by On Ramp High Level Overview ● How does your activity request new component from Android? – API calls – Via Intents ● Define what you would like to have happen next, ● Pass data to next activity ● Receive data back
- 29. 1 May 2013 Presented by On Ramp Presented by On Ramp Intents ● Intents – can be specific -i.e require specific class or – Ask for any activity that provides required service ● e.g view web page
- 30. 1 May 2013 Presented by On Ramp Presented by On Ramp Intents ● Intent made up of – Action: view web page,place call – Category: what attribute the component must have for your action e.g must display home screen – Extra: data to pass between components
- 31. 1 May 2013 Presented by On Ramp Presented by On Ramp Components Data Sharing ● How do components pass data between each other? – Bundles/Extra = can add data that needs to be transferred with Intent
- 32. 1 May 2013 Presented by On Ramp Presented by On Ramp Summary UI components belong to a task Platform creates components on you behalf API used to request component creation Components have a life cycle Components are building blocks for your app Other apps may use your components
- 33. 1 May 2013 Presented by On Ramp Presented by On Ramp Android Where to start? Start coding Activity components
- 34. 1 May 2013 Presented by On Ramp Presented by On Ramp Activities â—Ź Main entry point for application, â—Ź Configures user interface and handles events, â—Ź Each activity has one window in which to draw,
- 35. 1 May 2013 Presented by On Ramp Presented by On Ramp Activities ● UI layout is best done with xml resource files, ● Java code for handling events & setting up UI ● UI widgets extend View class – Views are the display classes used by an activity
- 36. 1 May 2013 Presented by On Ramp Presented by On Ramp Activity UI Layout â—Ź ADT plugin provides designer â—Ź Similar to XHTM:
- 37. 1 May 2013 Presented by On Ramp Presented by On Ramp Activity Lifecycle
- 38. 1 May 2013 Presented by On Ramp Presented by On Ramp Activities Screen Flow â—Ź Flow between activities or screens is not direct, â—Ź Application framework handles this for you â—Ź You ask framework to create next screen you wish to display
- 39. 1 May 2013 Presented by On Ramp Presented by On Ramp Activities Screen Flow ● API Calls - – startActivity(Intent) – startActivityForResult(Intent)
- 40. 1 May 2013 Presented by On Ramp Presented by On Ramp Resources â—Ź Resources are static content â—Ź Resources are managed by generated code â—Ź Layout definitions â—Ź Images â—Ź String constants â—Ź Resource ids
- 41. 1 May 2013 Presented by On Ramp Presented by On Ramp Resources ● Resources are defined in ● xml files, ● Images in folders – Resources directory = res – Naming of directories is important
- 42. 1 May 2013 Presented by On Ramp Presented by On Ramp Application Configuration ● Applications are groupings of components – Activities, – Services – Broadcast receivers – Content provider
- 43. 1 May 2013 Presented by On Ramp Presented by On Ramp Application Configuration ● Apps are defined via manifest.xml – <application> defines ● launcher activity for app, ● what intents your components are created to handle – <uses-permission> to identify what services your application requires access to
- 44. 1 May 2013 Presented by On Ramp Presented by On Ramp Security ● Linux layer – process level security, – File level security ● Application layer – Request permission from user to access services – manifest.xml <use-permission>
- 45. 1 May 2013 Presented by On Ramp Presented by On Ramp Contact Info ● On Ramp Web Site – http://www.onramp.mobi ● Social Networks - – Twitter @mxc4 – G+ MClarke4 ● Email: – support@onramp.mobi – mark@onramp.mobi