Android Learning notes (i)

First, the Android system architecture

1.Linux kernel

Based on the Linux2.6 core, provides low-level driver (display driver, audio driver, camera driver, Bluetooth driver, Wi-Fi driver, power management, etc.) for various hardware

2. System Runtime Layer

Provides key feature support for Android systems through a number of C + + libraries (SQLite library provides database support, opengl| The ES Library provides support for 3D drawings, the WebKit library provides support for the browser kernel, and the Android Runtime library for developers to write Android apps that run on Dalvik virtual machines.

3. Application Framework Layer

API for Applications

4. Application Layer

A program that is developed to run

Second, Android app

1. Four components

Activity: The façade of the application layer, and everything you can see in the application layer is placed in the activity.

Service: Running in the background, exiting the app can still continue to run

Broadcast Receivers (Boadcast receiver): Messages can be accepted and sent

Content Provider: Sharing data between applications

Android Learning notes (i)