Android 新手入门之剖析 Android 程序结构

核心提示：messages or change settings. Each of these screens would be implemented as an activity. Moving to another screen is accomplished by a starting a new activity. I

messages or change settings. Each of these screens would be implemented as an activity. Moving to another screen is accomplished by a starting a new activity. In some cases an activity may return a value to the previous activity -- for example an activity that lets the user pick a photo would return the chosen photo to the caller. )

当一个新屏幕打开时，上一个屏幕将暂停并放入到历史栈中，用户可以浏览通过以前打开的屏幕在历史栈中，屏幕也可以选择被一处从历史栈当它不再保留时。Android保留每一个从主屏幕启动的程序到历史栈。(When a new screen opens, the previous screen is paused and put onto a history stack. The user can navigate backward through previously opened screens in the history. Screens can also choose to be removed from the history stack when it would be inappropriate for them to remain. Android retains history stacks for each application launched from the home screen. )