onRestoreInstanceState 没有被调用

Question

我想在应用程序进入 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 从未被调用。

我知道 onRestoreInstanceState 和 onSaveInstanceState 都不属于应用程序生命周期的一部分，那么为什么 onSaveInstanceState 会被调用，而 onRestoreInstanceState 不会被调用呢？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);
}

日志猫：

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()仅在之后调用onStart()，因此不会在之后调用onResume()。检查这个完整的活动生命周期。

我希望这有帮助！