Android-First chapter

Android System Architecture

Android can be roughly divided into four-storey structure, five areas;

1. Linux kernel layer: provides the underlying driver;
2. System Runtime Layer: This layer provides key feature support for Android systems through a number of C + + libraries.

   Also on this tier is the Android runtime library, which mainly provides core libraries that allow developers to
   Use the Java language to write Android apps

3. Application Framework layer: This layer primarily provides the various APIs that may be used to build the application
4. Application layer: Simply speaking, it is an installed application.

Four components

1. Activity activities
2. Services Service
3. Broadcast receivers
4. Content providers

What we see is basically the interface that the activity gives me, which is basically the UI interface, the service runs in the background, and even if you quit the app, the service continues to run. The broadcast receiver, as its name implies, receives broadcast information (the equivalent of a signal) from various applications. The content provider, however, provides the possibility of sharing data between applications.

Android-First chapter