setMaxDuration failed when creating Android video recoder

I'm currently trying to create a very simple video recorder on Android without using intent, just a custom app. My code snippet is following

import java.io.IOException;


import android.app.Activity;
import android.media.MediaRecorder;
import android.net.NetworkInfo;
import android.os.Bundle;
import android.util.Log;
import android.view.SurfaceHolder;
import android.view.SurfaceVie开发者_C百科w;

public class CameraActivity extends Activity implements SurfaceHolder.Callback {
    public enum State {
        UNKNOWN, CONNECTED, NOT_CONNECTED
    }

SurfaceView cameraView;
SurfaceHolder holder;
public boolean mListening;
public Object mState;
public NetworkInfo mNetworkInfo;

public boolean mSending;

boolean recording = false;
public static final String TAG = "VIDEOCAPTURE";
private MediaRecorder recorder;

protected void captureVideo() {
    if (recording) {
        recorder.stop();
        // recorder.release();
        recording = false;
        Log.v(TAG, "Recording Stopped");
        // Let's initRecorder so we can record again
        initRecorder();
        prepareRecorder();
    } else {
        recording = true;
        recorder.start();
        Log.v(TAG, "Recording Started");
    }

}

private void initRecorder() {
    recorder.setAudioSource(MediaRecorder.AudioSource.DEFAULT);
    recorder.setVideoSource(MediaRecorder.VideoSource.DEFAULT);
    recorder.setOutputFile("/sdcard/videocapture_example.mp4");
    recorder.setMaxDuration(50000); // 50 seconds
    recorder.setMaxFileSize(5000000); 
}

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    recorder = new MediaRecorder();
    initRecorder();
    setContentView(R.layout.main);
    cameraView = (SurfaceView) this.findViewById(R.id.CameraView);
    holder = cameraView.getHolder();
    holder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
    holder.addCallback(this);
}

private void prepareRecorder() {
    recorder.setPreviewDisplay(holder.getSurface());
    try {
        recorder.prepare();
    } catch (IllegalStateException e) {
        e.printStackTrace();
        finish();
    } catch (IOException e) {
        e.printStackTrace();
        finish();
    }
}

@Override
public void surfaceChanged(SurfaceHolder holder, int format, int w, int h) {
}

@Override
public void surfaceCreated(SurfaceHolder holder) {
    Log.v(TAG, "surfaceCreated");
    prepareRecorder();
}

@Override
public void surfaceDestroyed(SurfaceHolder holder) {
    // camera.stopPreview();
    // camera.release();
    Log.v(TAG, "surfaceDestroyed");
    if (recording) {
        recorder.stop();
        recording = false;
    }
    recorder.release();
    finish();
}

}

But when i deployed this code within emulator, in the LogCat i got some errors like this.

java.lang.RuntimeException: Unable to start activity ComponentInfo...

java.lang.RuntimeException: setMaxDuration failed. at android.media.MediaRecorder.setMaxDuration(Native Method)

What wrong with my code?

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Quote from http://developer.android.com/reference/android/media/MediaRecorder.html: "Note: Currently, MediaRecorder does not work on the emulator."