Activity 生命周期

/** * 程序启动：   onCreate -> onStart -> onResume * HOME键:  onSaveInstanceState -> onPause -> onStop * BACK键： finish -> onPause -> onStop -> onDestory * 再次执行：   onRestart -> onStart -> onResume * 横屏<-->竖屏(切换) * onSaveInstanceState -> onPause -> onStop --> onDestory --> onCreate -> onStart -> onResume *  * 调用finish onPause -> onStop -> onDestroy  (程序结束) * 再次执行       onCreate -> onStart -> onResume (重新启动) * killProcess的时候系统不执行onDestroy;直接杀死 * -------------------------------------------- * 两个activity之间的跳转 * 启动A_onCreate -> A_onStart -> A_onResume * **intent跳转(A->B) A_onSaveInstanceState -> A_onPause ->  *                  B_onCreate -> B_onStart -> B_onResume -> A_onStop * **back跳转(B->A) B_onPause ->  A_onRestart -> A_onStart -> A_onResume *                B_onStop -> B_destroy  */