儲存activity的資料

 protected void onSaveInstanceState(Bundle outState);

onSaveInstanceState is called before onPause(), onStop(), and onDestroy()

將資料存到bundle，之後再從bundle讀取

ex:


@Override
    public void onSaveInstanceState(Bundle savedInstanceState) {
        super.onSaveInstanceState(savedInstanceState);
        savedInstanceState.putInt("currentIndex",  mCurrentIndex);
    }

說明: 儲存

 @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

         if (savedInstanceState != null) {

            mCurrentIndex = savedInstanceState.getInt(KEY_INDEX, 0);

        }

    }

說明: 讀取, 也可以override onRestoreInstanceState method讀取儲存的資料。


當使用者從App主畫面按下back鍵，存到bundle的資料將被清空