onRestoreInstanceState没有被调用

Question

当应用程序进入textView时，我想保存onPause的值。所以我实现了onSaveInstanceState和onRestoreInstanceState。但是，如下所示，logcat输出中从未调用onRestoreInstanceState。

我知道onRestoreInstanceState和onSaveInstanceState都不是应用程序生命周期的一部分，那么为什么onSaveInstanceState会被调用，而onRestoreInstanceState却没有呢？如何打电话给onRestoreInstanceState？

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);
}

logcat

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()只在onStart()之后被调用，所以在onResume()之后不调用它。检查这个完整的活动生命周期。

​

​

我希望这能帮到你!

Answer 2

正如正式参考书所说的关于onSaveInstanceState

此方法在活动可能终止之前被调用。

如果有可能杀死一个，那么onSaveInstanceState就会被称为onSaveInstanceState，不管它是否已经被杀死。

当onRestoreInstanceState被调用时，实际上已经杀死了Activity。

因此，如果Activity实际上没有被杀死，则不会调用onRestoreInstanceState。

因此，onSaveInstanceState和onRestoreInstanceState之间的不对称调用就会发生。如果您想确保被称为onRestoreInstanceState，您肯定应该杀死您的Activity。