Xamarin Android.Speech识别器意图不会调用OnActivityResult

Question

当我在android中使用Speech Recognizer Intent时。 intent永远不会调用OnActivityResult方法。调试器永远不会在方法的第一行捕获它。此示例从示例here进行了修改，以合并Xamarin Forms。

private const int Voice = 10;

public void RecordSpeech()
{
    Intent voiceIntent = new Intent(RecognizerIntent.ActionRecognizeSpeech);
    voiceIntent.PutExtra(RecognizerIntent.ExtraLanguageModel, RecognizerIntent.LanguageModelFreeForm);
    voiceIntent.PutExtra(RecognizerIntent.ExtraSpeechInputCompleteSilenceLengthMillis, 1500);
    voiceIntent.PutExtra(RecognizerIntent.ExtraSpeechInputPossiblyCompleteSilenceLengthMillis, 1500);
    voiceIntent.PutExtra(RecognizerIntent.ExtraSpeechInputMinimumLengthMillis, 15000);
    voiceIntent.PutExtra(RecognizerIntent.ExtraMaxResults, 1);
    voiceIntent.PutExtra(RecognizerIntent.ExtraLanguage, Java.Util.Locale.Default);
    ((Activity)Forms.Context).StartActivityForResult(voiceIntent, Voice);
    //This doesn't work either
    //((Activity)Forms.Context).StartActivityForResult(Intent.CreateChooser(new Intent(voiceIntent), "voiceIntent"), Voice);
}

protected override void OnActivityResult(int requestCode, Result resultVal, Intent data)
{ //A break point here doesn't work
    Debug.WriteLine("Debug");
    if (requestCode == Voice)
    {
        if (resultVal == Result.Ok)
        {
                IList<string> matches = data.GetStringArrayListExtra(RecognizerIntent.ExtraResults);
            if (matches.Count != 0)
            {
                Debug.WriteLine(matches[0]);
            }
        }
    }
    base.OnActivityResult(requestCode, resultVal, data);
}

Answer 1

OnActivityResult需要位于MainActivity类中。把它放在那里固定一切。