void _recordingButton_TouchCancel(object sender, EventArgs e) { if (_recorder == null) { // during playing, it can not record. stopPlayback(); _playBackButton.Enabled = false; // setting audio session AudioSession.Category = AudioSessionCategory.RecordAudio; _recorder = new AudioQueueRecorder(_url); _recorder.Start(); _recordingButton.SetTitle("Stop Recording", UIControlState.Normal); } else { _recorder.Dispose(); _recorder = null; _recordingButton.SetTitle("Start Recording", UIControlState.Normal); _playBackButton.Enabled = true; // setting audio session AudioSession.Category = AudioSessionCategory.MediaPlayback; } }