Introduction to Android

译自：http://developer.android.com/guide/index.html # Introduction to Android

初识Android

android提供了一个强大的app framework以供用java写出各种优秀的程序和游戏。

android提供了丰富的组件以来编写app

app由各种组件组合而成，比如，一个单独的activity就是一个用户界面，一个单独的Service可以提供后台服务。

一个组件又可以通过intent调用其他（程序）的组件

From one component you can start another component using an intent. You can even start a component in a different app, such an activity in a maps app to show an address. This model provides multiple entry points for a single app and allows any app to behave as a user's "default" for an action that other apps may invoke.