在 onActivityCreated() 之后再次调用 Fragment 的 onAttach()

Posted 2023-04-19

【中文标题】在 onActivityCreated() 之后再次调用 Fragment 的 onAttach()

【英文标题】：Fragment's onAttach() called again after onActivityCreated()

【发布时间】：2019-10-25 01:52:06

【问题描述】：

我正在添加一个带有编辑文本和复选框的片段，并且我正在尝试在方向更改后保存视图的状态，但我无法这样做。 谁能告诉我为什么在 onActivityCreated() 之后再次调用 onAttach() 方法？当我旋转我的设备一次时会发生这种情况，因此我无法保存我的状态。这真的很奇怪，我被困在这个问题上。

BlankFragment.java

@Override
public void onAttach(Context context) 
    super.onAttach(context);
    Log.d("loggggggggg","onAttach() called!");


@Override
public void onCreate(@Nullable Bundle savedInstanceState) 
    super.onCreate(savedInstanceState);
    Log.d("loggggggggg","onCreate() called!");


@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, 
Bundle savedInstanceState) 
    Log.d("loggggggggg","onCreateView() called!");
    View v = inflater.inflate(R.layout.fragment_blank, container, false);
    ed = v.findViewById(R.id.edit);
    cb = v.findViewById(R.id.check);
    if(savedInstanceState != null)
        ed.setText(savedInstanceState.getString("string"));
        cb.setChecked(savedInstanceState.getBoolean("bool"));
    
    return v;


@Override
public void onActivityCreated(@Nullable Bundle savedInstanceState) 
    super.onActivityCreated(savedInstanceState);
    Log.d("loggggggggg","onActivityCreated() called!");


@Override
public void onStart() 
    super.onStart();
    Log.d("loggggggggg","onStart() called!");


@Override
public void onResume() 
    super.onResume();
    Log.d("loggggggggg","onResume() called!");


@Override
public void onPause() 
    super.onPause();
    Log.d("loggggggggg","onPause() called!");


@Override
public void onStop() 
    super.onStop();
    Log.d("loggggggggg","onStop() called!");


@Override
public void onDestroyView() 
    super.onDestroyView();
    Log.d("loggggggggg","onDestroyView() called!");


@Override
public void onDestroy() 
    super.onDestroy();
    Log.d("loggggggggg","onDestroy() called!");


@Override
public void onDetach() 
    super.onDetach();
    Log.d("loggggggggg","onDetach() called!");


@Override
public void onSaveInstanceState(@NonNull Bundle outState) 
    Log.d("loggggggggg","onSavedInstance() called!");
    outState.putString("string",ed.getText().toString());
    outState.putBoolean("bool",cb.isChecked());
    super.onSaveInstanceState(outState);


Log after screen rotation

D/loggggggggg: onPause() called!
D/loggggggggg: onSavedInstance() called!
D/loggggggggg: onStop() called!
D/loggggggggg: onDestroyView() called!
D/loggggggggg: onDestroy() called!
onDetach() called!
D/loggggggggg: onAttach() called!
onCreate() called!
D/loggggggggg: onCreateView() called!
D/loggggggggg: onActivityCreated() called!
D/loggggggggg: onAttach() called!           //why is this happening
onCreate() called!
D/loggggggggg: onDestroyView() called!
onDestroy() called!
onDetach() called!
D/loggggggggg: onCreateView() called!
D/loggggggggg: onActivityCreated() called!
onStart() called!
D/loggggggggg: onResume() called!

【问题讨论】：

也请添加日志

我在最后的代码后面加了

我的意思是显示来自 logcat 的日志

【参考方案1】：

您可以删除 onAttach() 方法，因为它是不必要的 :) 你可以告诉我们 logcat 的错误是什么:)