The first line of code learning note 1-android system architecture

1.2013.10,andy Rubin founded the Android company. 2005.8,google acquired it and launched the first version of Android system in 2008.

2.①linux Kernel: Linux 2.6 based.

Display Driver: Linux-based framebuffer (frame buffer) driver.

Camera Driver: Common Linux-based v412 (Video for Linux) drivers.

Bluetooth Driver: Wireless transmission technology based on IEEE 802.15.1 standard.

Flash Memory Driver: MTD-based flash driver.

A special driver for the Binder (IPC) driver:android, which has a separate device node that provides the ability to communicate between processes.

USB Driver: An external bus standard that regulates the connection and communication of computers to external devices.

Keypad Driver: As the key-zone driver for the input device.

WiFi Driver: Based on the IEEE 802.11 standard driver.

Audio Drivers: A popular ALSA-based Advanced Linux sound System driver.

Power Management: battery power, etc.

②libraries: Provides key technical support for Android systems through a number of C + + libraries.

Surface Manager:android is one of the framework class libraries that manage access to the display subsystem and seamlessly integrate 3D graphics from multi-module applications.

Media framework:android System Multimedia Library, based on Packervideo Opencore, the library supports a variety of common formats for audio, video playback and recording, as well as images such as MPEG4, MP3, AAC, AMR, JPG, PNG, etc.

SQLite: A lightweight database that adheres to the acid-based relational database management system, which is contained in a relatively small C library.

opengl| Es:3d drawing, a subset of OpenGL's three-dimensional graphics API, is designed for embedded devices such as mobile phones, PDAs, and game consoles.

FreeType: bitmaps and vectors.

WebKit: Provides support for the browser kernel.

sgl:2d Graphics Engine Library.

SSL: is located between the TCP/IP protocol and various application layer protocols, which provides support for data communication.

Libc:ansi c is the basic C-language function library, which contains the most basic library functions of C language.

Android Runtime: In the Android operating system, each Java program runs on the Dalvik virtual machine, It can only execute the. Dex executable file, and when the Java program is compiled, it needs to be converted to. dex format by the DX tool in the SDK to perform properly on the virtual machine, the Java Virtual machine runs Java bytecode, and the Dalvik virtual machine runs its proprietary file format, Dex (Dalvik exceutable) files.

Dalvik virtual machines have the following key features:

1. Proprietary DEX file format.

2.dex optimization, the structure of the Dex file is compact.

3. Register-based.

4. An application, a virtual machine instance, a process. Every Android app runs in a single Dalvik virtual machine instance, and each virtual machine instance is a separate process space.

Dalvik is specifically designed for mobile devices, which are optimized for mobile memory and CPU performance.

③application Framework: Provides a variety of APIs that you might use to build your application.

Activity Manager: Used to manage the application life cycle and provide common navigation fallback functionality.

Window Manager: Manages all of the Windows programs.

Content Providers: You can have one app access data from another app, or share their own data.

View System: Can be used to build an application that includes lists, grids, text boxes, buttons, and embeddable Web browsers.

Notification Manager: The app can display a custom prompt in the status bar.

Program management within the package manager:android system.

Telephony Manager: Provides a collection of get methods for accessing status and information related to mobile communication. These include mobile SIM status and information, the status of the telecommunications network, and the information of mobile phone users.

You can use these get methods in your application to get related data.

Resource Manager: Provides access to non-code resources, such as local strings, graphics, and layout files.

Location Manager: The core component of position services, which provides a series of methods to handle location-related issues, including querying a known location, registering and unregistering periodic location updates from a locationprovider,

The triggering of a defined intent when registering and unregistering close to a certain coordinate.

XMPP Service: Online instant communication software A common process is the background push service.

④applications: A program written in the Java language on a virtual machine.

　　

The first line of code learning note 1-android system architecture