App components are the essential building blocks of an Android app. Each component is an entry point through which the system or a user can enter your app. Some components depend on others.
- Abstract class to implement, support access to app resources, lauch activity/service/broadcast receiver.
- Provide context of current state of app environment data.
Main control unit. Provide UI for user to interact. Which included Window - carrier and Views - display.
Long-running operation in background (can be in UI thread or worker thread), no UI and user interact.
Enable system to deliver events to the app and the OS (outside user's flow) or communicate between components.
Manage set of shared data in system. Share and access data of other app. Use ContentResolver to resolve URI to specific content provider.
Message object to request action.
Schedule Message and Runable to be execute at some point or enqueue action to perform in different thread. Main part of HandlerThread - a thread that has a looper.
To generate IPC code.