關於savedInstanceState

參考https://www.jianshu.com/p/aaea251af09e
@Override
protected void onSaveInstanceState(Bundle outState) {
    super.onSaveInstanceState(outState);
}

發生情況：應用退到後臺被回收、旋轉屏幕的時候。可用Bundle保存值

onCreate(Bundle savedInstanceState)應用被創建的時候獲取onSaveInstanceState保存的值

onRestoreInstanceState 獲取onSaveInstanceState保存的值