savedInstanceState在onCreate中始終為null值

Question

這是我的onCreate方法在一個片段的子類中

static  int counter = 0;
@Override
public void onCreate(Bundle savedInstanceState){
    super.onCreate(savedInstanceState);
    if(savedInstanceState == null) { //made for first time
        Log.d("came in", "Came in");
        counter = 0;
    } else {
        counter = savedInstanceState.getInt("counter", 0);
    }
}

這是我的saveInstanceState方法

@Override
public void onSaveInstanceState(Bundle outState){
    super.onSaveInstanceState(outState);
    Log.d("hi there", ""+counter); // this is printing hi there 3
    outState.putInt("counter", counter);//key value pair
}

但是在onCreate方法中，savedInstanceState始終為null，並且可以打印。

Answer 1

覆蓋protected void onRestoreInstanceState(Bundle savedInstanceState)並查看是否可以在那里獲取值。

Answer 2

嘗試將您的值保存在片段主機活動（定義片段的活動）中。 從主機活動中，您必須提取該值並在片段子類中訪問它。

Answer 3

嘗試將您的方法onSaveInstanceState更改為：

@Override
public void onSaveInstanceState(Bundle outState){    
    Log.d("hi there", ""+counter); // this is printing hi there 3
    outState.putInt("counter", counter);//key value pair
    super.onSaveInstanceState(outState); // call super after put int
}