android - onRestoreInstanceState 没有被调用

Question

我想在 App 进入 onPause 时保存 textView 的值。所以我实现了 onSaveInstanceState 和 onRestoreInstanceState。但如下面的 logcat 输出所示，onRestoreInstanceState永远不会被调用。

我知道 onRestoreInstanceState 和 onSaveInstanceState 都不是 App 生命周期的一部分，那么为什么 onSaveInstanceState 被调用而 onRestoreInstanceState 没有被调用？以及如何调用 onRestoreInstanceState？

代码:

@Override
protected void onResume() {
    // TODO Auto-generated method stub
    super.onResume();
    Log.w(TAG, LogAnd.i("onResume", ""));

    btAdapter = BluetoothAdapter.getDefaultAdapter();
    if (btAdapter == null) {
        tvStatus.setText("[" + SysUtils.getDeviceName() + "] no Bluetooth installed.");
    } else {
        tvStatus.setText("[" + SysUtils.getDeviceName() + "] Bluetooth installed.");
    }
}

@Override
protected void onSaveInstanceState(Bundle outState) {
    // TODO Auto-generated method stub
    super.onSaveInstanceState(outState);
    Log.w(TAG, LogAnd.i("onSaveInstanceState", ""));

    outState.putString("statusText", tvStatus.getText().toString());
}

@Override
protected void onRestoreInstanceState(Bundle savedInstanceState) {
    // TODO Auto-generated method stub
    super.onRestoreInstanceState(savedInstanceState);
    Log.w(TAG, LogAnd.i("onRestoreInstanceState", ""));

    String status = savedInstanceState.getString("statusText");
    tvStatus.setText(status);
}

日志:

08-23 18:36:31.544: W/MainActivity(32195): -> onResume:
08-23 18:36:31.904: W/MainActivity(32195): -> onPause:
08-23 18:36:32.694: W/MainActivity(32195): -> onSaveInstanceState:
08-23 18:36:34.014: W/MainActivity(32195): -> onResume:
08-23 18:36:42.904: W/MainActivity(32195): -> onPause:
08-23 18:36:43.784: W/MainActivity(32195): -> onSaveInstanceState:
08-23 18:36:43.784: W/MainActivity(32195): -> onStop:
08-23 18:36:50.084: W/MainActivity(32195): -> onStart:BT-Receiver Registered
08-23 18:36:50.084: W/MainActivity(32195): -> onResume:

Answer 1

onRestoreInstanceState() 仅在 onStart() 之后调用，因此不会在 onResume() 之后调用。检查这个完整的 Activity 生命周期。

希望对您有所帮助!