1 Android Workshop Platform Overview

2 What is Android?  Android is a software stack for mobile devices that includes an operating system, middleware and key applications.

What is Middleware?  The Android operating system uses the Linux kernel at its core, and also provides an application framework that developers incorporate into their applications.  In addition, Android provides a middleware layer including libraries that provide services such as data storage, screen display, multimedia, and web browsing.  Because the middleware libraries are compiled to machine language, services execute quickly.  Middleware libraries also implement device-specific functions, so applications and the application framework need not concern themselves with variations between various Android devices.  Android's middleware layer also contains the Dalvik virtual machine and its core Java application libraries. 3

4 OHA (Open Handset Alliance)  A business alliance consisting of 47 companies to develop open standards for mobile devices

5 Phones HTC G1, Droid, Tattoo Motorola Droid (X) Suno S880Samsung Galaxy Sony Ericsson

6 Tablets Velocity Micro Cruz Gome FlyTouchAcer beTouch Dawa D7 Toshiba Android SmartBook Cisco Android Tablet

7 Architecture

8 Android S/W Stack - Application  Android provides a set of core applications: Client SMS Program Calendar Maps Browser Contacts Etc  All applications are written using the Java language.

9 Android S/W Stack – App Framework  Enabling and simplifying the reuse of components Developers have full access to the same framework APIs used by the core applications. Users are allowed to replace components. Any application can publish its capabilities and any other application may then make use of those capabilities.

10 Android S/W Stack – App Framework (Cont)  Features FeatureRole View System Used to build an application, including lists, grids, text boxes, buttons, and embedded web browser Content Provider Enabling applications to access data from other applications or to share their own data Resource Manager Providing access to non-code resources (localized strings, graphics, and layout files) Notification Manager Enabling all applications to display customer alerts in the status bar Activity Manager Managing the lifecycle of applications and providing a common navigation backstack

11 Android S/W Stack - Libraries  Including a set of C/C++ libraries used by components of the Android system  Exposed to developers through the Android application framework NameExplanation Media libraryFor playback of audio and video media Surface managerTo provide display managment SGL and OpenGLFor 2D and 3D graphics SQLiteFor native database support SSL and WebKitFor integrated web browser and Internet security

12 Android S/W Stack - Runtime  Core Libraries Providing most of the functionality available in the core libraries of the Java language APIs  Data Structures  Utilities  File Access  Network Access  Graphics  Etc

13 Android S/W Stack – Runtime (Cont)  Dalvik Virtual Machine Providing environment on which every Android application runs  Each Android application runs in its own process, with its own instance of the Dalvik VM.  Dalvik has been written such that a device can run multiple VMs efficiently. Register-based virtual machine

14 Android S/W Stack – Runtime (Cont)  Dalvik Virtual Machine (Cont) Executing the Dalvik Executable (.dex) format .dex format is optimized for minimal memory footprint.  Compilation Relying on the Linux Kernel for:  Threading  Low-level memory management

15 Android S/W Stack – Linux Kernel Relying on Linux Kernel 2.6 for core system services Memory and Process Management Network Stack Driver Model Security Providing an abstraction layer between the H/W and the rest of the S/W stack

16 Android Versions

17 What Makes an Android Application?

18 Activities Your application’s presentation layer. It uses Views to form graphical user interface that display information and respond to user actions. Activity is equivalent to a Form in term of Windows Application.

19 Services The invisible workers of your application. Service components running in background, updating your data sources and visible Activities and triggering Notifications. They are used to perform regular processing that needs to continue even when your application’s Activities are not active or visible

20 Content Providers Shareable data stores. They are used to manage and share application database. You can configure your own Content provider to permit access from other applications and use Content providers exposed by others to access their stored data.

21 Intents An inter-application message passing framework. Using Intents you can broadcast message system-wide or to a target Activity or Service. An inter-activity navigation and message passing can be also done using Intents.

@2011 Mihail L. Sichitiu22 Broadcast Receivers Intent broadcast consumers. You can create and register a Broadcast Receiver, your application can listen for broadcast Intents that can match specific filter criteria.

@2011 Mihail L. Sichitiu23 Widgets Visual application components that can be added to the home screen.

@2011 Mihail L. Sichitiu24 Notifications A user notification framework.

25 Platform VersionAPI LevelVERSION_CODE Android ICE_CREAM_SANDWICH_ MR1 Android 4.0, 4.0.1, ICE_CREAM_SANDWICH Android 3.213HONEYCOMB_MR2 Android 3.1.x12HONEYCOMB_MR1 Android 3.0.x11HONEYCOMB Android Android GINGERBREAD_MR1 Android Android Android 2.3 9GINGERBREAD Android 2.2.x8FROYO Android 2.1.x7ECLAIR_MR1 Android ECLAIR_0_1 Android 2.05ECLAIR Android 1.64DONUT Android 1.53CUPCAKE Android 1.12BASE_1_1

@2011 Mihail L. Sichitiu26 Activity Lifecycle

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28 Lifecycle Methods onCreate() ::This method is called when first time activity is created. onStart()::This method is called just before your activity becomes visible on the screen. onResume()::This method is called after onStart() method and if your activity is the foreground activity on the screen. onPause()::This method is called when your activity is just about to call another activity so that the current activity has to be paused and the new activity has to be resumed. Here the previous activity is not stopped but it loss the foreground visibility means it goes as background activity. onStop()::This method is called when your activity is no longer visible on the screen. onDestroy()::This method is called when your current activity has the last chance to do any processing before it is destroyed.