文档介绍：Android教程01-平台概述12194
课程结构
目标：了解智能手机开发现状，Android平台体系结构和应用程序模型，覆盖了几个主要技术应用。
平台综述
开发环境
程序结构
数据存取
网络连接
硬件访问
图ive Servers-Audio
音频处理
Hardware Abstraction Libs
硬件虚拟层
User space C/C++ library layer
硬件接口驱动
使Android平台逻辑与硬件接口分离
Andoid Runtime
应用开发语言：Java
Dalvik虚拟机
指令 : Dalvik Excutable
Java标准库
把java代码编译为Dalvik可执行文件(dex format)
运行环境
核心库提供的Java 功能Dalvik 虚拟机依赖于Linux 内核，
可同时运行多个Dalvik 虚拟机，
每一个Android 应用程序在它自己的Dalvik VM 实例中运行VM 执行优化的Dalvik 可执行文件(.dex)
Dx-工具把编译过的Java 文件转换为dex 文件
Dalvik Virtual Machine
Android custom implementation virtual machine
Provides application portability and runtime consistency
Runs optimized file format (.dex) and Dalvik bytecode
Java .class / .jar files converted to .dex at build time
Designed for embedded environment
Supports multiple virtual machine processes per device
Highly CPU-optimized bytecode interpreter
Efficiently Using runtime memory
Core Libraries
Core APIs for Java language provide a powerful, yet simple and familiar development platform
DVM vs JVM
DVM
Google
Dalvik excutable
JVM
Sun
Java bytecode
Application Framework
Applications Framework
Activity manager
管理运行应用程序
Content Provider
在各应用之间共享数据
Resource Manager
管理非代码资源
Notification Manager
显示用户提示和状态栏
Views System
可扩展显示，可构建UI
应用和框架
核心应用，例如联系人，电子邮件，电话，浏览器，日历，地图， ...
充分访问所有核心应用框架API
简化组件的重用
用Java 编写应用程序
Applications
JAVA编写的应用程序
开发环境
IDE – Eclipse
Eclipse plug-in - ADT
Software Development Kit (SDK)
Android Emulator
Debugger
Constants
int
BASE
Oct. 2019
The original, first, version of Android.
int
BASE_1_1
Feb. 2009
First Android update, officially called .
int
CUPCAKE
May 2009
Android .
int
CUR_DEVELOPMENT
Magic version number for a current development build, which has not yet turned into an official release.
int
DONUT
Sep. 2009
Android .
int
ECLAIR
Nov. 2009
Android : Applications targeting this or a later release will get these new changes in behavior:
The function will return the new STAR