录制音频并重复检查振幅

Question

如果幅度大于给定的阈值，我想重复录制声音并在500ms后检查振幅，然后我想再进行一次活动。

但是当我尝试这样做时，我的活动会不断地像往复一样切换

 public class MediaSound extends Activity 
 {
MediaRecorder recorder;
String mFileName;
Handler mHandler;
boolean isRecording = false;
@Override
protected void onCreate(Bundle savedInstanceState) 
{
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    mHandler = new Handler();
}

private Runnable runnable = new Runnable()
{

    @Override
    public void run() 
    {
        // TODO Auto-generated method stub
        if( recorder != null)
        {
            int amplitude =recorder.getMaxAmplitude();
            //Log.d("AMPLITUDE----->", " "+amplitude);
            if(amplitude>10000)
            {
                next();
                            }
            }
         }
        mHandler.postDelayed(runnable, 500);
    }
};

@Override
protected void onStart() 
{
    super.onStart();
     recorder = new MediaRecorder();
     recorder.setAudioSource(MediaRecorder.AudioSource.MIC);
     recorder.setOutputFormat(MediaRecorder.OutputFormat.THREE_GPP);
     recorder.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB);
     Log.d("MediaSound", "I am in MediaSound");
     mFileName = Environment.getExternalStorageDirectory().getAbsolutePath();
     mFileName += "/audiorecordtest.3gp";
     recorder.setOutputFile(mFileName);
     try 
     {
        recorder.prepare();
     }
     catch (IllegalStateException e) 
     {
        e.printStackTrace();
     } 
     catch (IOException e) 
     {
        e.printStackTrace();
     }
     recorder.start();  
     mHandler.postDelayed(runnable, 500);
     if(isRecording)
     {

    }

}

public void next()
{
    mHandler.removeCallbacks(runnable);
    Log.d("In the next", "Kya karu");
    recorder.stop();
    recorder.release();
    this.finish();
    Intent newIntent = new Intent(getApplicationContext(), NewMedia.class);
    startActivity(newIntent);
}