APK File Dalvik executable This is the code that runs your application. Resources are everything that is not code. (XML,images ,video,layouts ,...etc) Native libraries (optionally)
INSTALLATION Installing Eclipse http://www.eclipse.org/downloads/ Installing the Android SDK Android Software Development Kit (SDK) is all you need to develop android application http://developer.android.com/sdk/installing.html
Activity Consider usually as asingle screen that user see on device like text apps . ex. website . Each activity has its own cycle . It is implemented as aclass . When new screen opens prev.one paused and put in history stack .
INTETS They are system msg running inside device notifies apps for events, from hardware state to incoming data For android to move from screen to screen called intent You create your own intent object to launch aother apps
service It is the code that long lived and run without UI ex.media player apps & network download Media player Activity could start service using Context.startservice() to run in background to keep music going
ContetProvider sharable data storage Enable data sharing between apps Simple interface with insert , update Android development encourage other apps to have data while mainting complete control over data how to get accessed It is aclass the implement standard set of methods