Issue when trying to play media file using android.media.MediaPlayer and SurfaceView?

I am trying to play a .mp4 file using the android.media.MediaPlayer class.I am trying it out on the emulator.Unfortunately all i see is a blank screen when running the application.

I have placed the file testmp4 in the folder mnt/sdcard/

Here is the code that i am using.Can someone tell me what i am doing wrong?

package com.mediaplayer;

import java.io.IOException;

import android.app.Activity;
import android.media.MediaPlayer;
import android.os.Bundle;
import android.view.SurfaceHolder;
import android.view.SurfaceView;

public class MyPlayBack extends Activity implements SurfaceHolder.Callback{
    /** Called when the activity is first created. */
    private  MediaPlayer mediaPlayer;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

         mediaPlayer=new MediaPlayer();
        SurfaceView surface=(SurfaceView)findViewById(R.id.surface);
        SurfaceHolder holder=surface.getHolder();
        holder.addCallback(this);
        holder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
        holder.setFixedSize(400, 300);
    }

    @Override
    public void surfaceChanged(SurfaceHolder 开发者_如何学JAVAholder, int format, int width,
            int height) {
        // TODO Auto-generated method stub



    }

    @Override
    public void surfaceCreated(SurfaceHolder holder) {
        // TODO Auto-generated method stub
        mediaPlayer.setDisplay(holder);
        try {
            mediaPlayer.setDataSource("/sdcard/testmp4.mp4");
            mediaPlayer.prepare();
            mediaPlayer.start();
        } catch (IllegalArgumentException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (IllegalStateException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }


    }

    @Override
    public void surfaceDestroyed(SurfaceHolder holder) {
        // TODO Auto-generated method stub
        mediaPlayer.release();
    }
}

main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    >
<SurfaceView
 android:id="@+id/surface"
 android:layout_width="wrap_content"
 android:layout_height="wrap_content"
 android:layout_gravity="center"
 />
</LinearLayout>

Edit:Lately i found that when I keep the application running for a long time.I see the blank white screen.But when i press the back button I can see that the frame of the video clip for a sec before the application closes.I think that the video is playing behind the white screen.How to bring it upfront.

Why re-invent the wheel? Use VideoView, it is meant for that. If you want to see how to see it right, look at the VideoView source.

Also, emulators are no-good for using video. Use a real device for video application development / testing.