當裝置旋轉時android生命週期方法的呼叫順序

特別注意onSaveInstanceState並不是生命週期方法

當裝置旋轉時，通過Log可以看出：

裝置銷燬Activity例項：

01-05 20:07:11.289 7860-7860/? D/QuizActivity: onPause(Bundle) called

01-05 20:07:11.290 7860-7860/? I/QuizActivity: onSaveInstanceState

01-05 20:07:11.290 7860-7860/? D/QuizActivity: onStop(Bundle) called

01-05 20:07:11.317 7860-7860/? D/QuizActivity: onDestroy(Bundle) called

重建Activity例項：

01-05 20:07:11.353 7860-7860/? D/QuizActivity: onCreate(Bundle) called

01-05 20:07:11.373 7860-7860/? D/QuizActivity: onStart(Bundle) called

01-05 20:07:11.377 7860-7860/? D/QuizActivity: onResume(Bundle)called

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*繼續深入

當我把setting->developer option->Don't keep activities開啟後再進行測試：

1. 點選Back鍵

   01-05 21:15:38.946 13590-13590/? D/QuizActivity: onPause(Bundle) called

   01-05 21:15:39.878 13590-13590/? D/QuizActivity: onStop(Bundle) called

   01-05 21:15:39.886 13590-13590/? D/QuizActivity: onDestroy(Bundle) called

   發現onSaveInstanceState並沒有被呼叫

2. 點選Home鍵

   01-05 21:17:43.975 13590-13590/? D/QuizActivity: onPause(Bundle) called

   01-05 21:17:44.723 13590-13590/? I/QuizActivity: onSaveInstanceState

   01-05 21:17:44.723 13590-13590/? D/QuizActivity: onStop(Bundle) called

   01-05 21:17:44.741 13590-13590/? D/QuizActivity: onDestroy(Bundle) called

當把Don't keep activities選項關閉後再進行上述相同測試發現：

唯一不同的是點選Home鍵依次執行：

01-05 21:17:43.975 13590-13590/? D/QuizActivity: onPause(Bundle) called

01-05 21:17:44.723 13590-13590/? I/QuizActivity: onSaveInstanceState

01-05 21:17:44.723 13590-13590/? D/QuizActivity: onStop(Bundle) called

Activity沒有被Destroy

而點選Back鍵，Activity都會被銷燬（也不會儲存activity的狀態，即：不呼叫onSaveInstanceState）。可以理解為Back鍵相當於通知系統“使用者不再需要當前的Activity”。

內容參考：Android程式設計權威指南