AndroidAndroid is a software platform for mobile devicesbased on the Linux Operating system an which isdeveloped by Google and Open Handset Alliance.Android is a software stack for mobile devices thatincludes an operating system and applications.
History of androidIt was Founded in Palo Alto, California , United Statesin October 2003 by Andy Rubin , Rich Miner, NickSears and Chris White.Google Inc. purchased the initial developer of thesoftware , Android Inc in 2005.
Comparison with symbianANDROID SYMBIANEasy to upgrade Upgrade is not availableProcessor is high Processor speed is lowLot of free apps in Google Less no of free apps in OVIplay storeSmooth handling Rough handlingUser friendly Not User Friendly
Comparison with windows ANDROID WINDOWS MOBILE Android is Open source Windows mobile is similar to Platform windows and has lot of legal bindings Google Play has more than Compare with android it has 500,000 apps only less no of apps and also no free apps With Google it is more No such features are here powerful with Google Maps and Google voice search Google Wallet app No such type of app is there Full , Multiple Account Sync Gmail support only through ,no outlook required outlook express.
Building and Running● Android asset packaging tool (aapt) crawls through the resource folder and generates an integer ID for every resource. These ID’s are written into R.java source file under generated sources folder where they can be accessed from application code.● Java compiler (javac) compiles the application’s java source files along with generated source files● Dexer (dx) translates the compiled Java bytecode into Dalvik bytecode (dex) format● Apkbuilder zips the resource table, application code and compiled resource into an apk file
Building and Running● Android programs are compiled into .dex (Dalvik Executable) files, which are in turn zipped into a single .apk file on the device. .dex files can be created by automatically translating compiled applications written in the Java programming language.
Building Blocks of Android● An Activity● An Intent● A Service● A Content provider● A Broadcast Receiver
An Activity● The activity is the most visible form of an Android application. An activity presents the UI to an application, along with the assistance of a class known as a view● An application may contain one or more activities. They are typically on a one-to-one relationship with the screens found in an application.
An intent● An application moves from one activity to another by calling a method known as Intent.
A Service● applications running "in the background"● The service is an Android application that has no UI
Life-Cycle of Activity● onCreate(): Called when the activity is first created An activity does all its initial setup of global state Always followed by onStart()
Life-Cycle of Activity● onRestart() called after the activity has been stopped. Always followed by onStart()
Life-Cycle of Activity● onStart(): Called just before the activities become visible to the user Followed by onResume() if the activity comes to the foreground
Life-Cycle of Activity● onResume() Called just before the activity starts interacting with the user always followed by onPause()
Life-Cycle of Activity● onPause(): Called when the system is about to start resuming another activity The next Activity will not resumed until it returns. Followed either by onResume() if the activity returns back to the front, or by onStop if it comes invisible to user.
Life-Cycle of Activity● onStop: Called when the Activity is no longer visible to user. Because it is being destroyed or another activity has been resumed. Followed either by onRestart() if the activity is coming back to interact with the user, or by onDestroy() if this activity is going away.
Life-Cycle of Activity● onDestroy(): Called before the activity is destroyed Final call that the activity will receive