MediaPlayer mediaPlayer = new MediaPlayer();
String path = "";

mediaPlayer.setLooping(true); //ループ再生の設定

try {
	mediaPlayer.setDataSource(path);
} catch (IllegalArgumentException e) {
	e.printStackTrace();
} catch (IllegalStateException e) {
	e.printStackTrace();
} catch (IOException e) {
	e.printStackTrace();
}

try {
	mediaPlayer.prepare();
} catch (IllegalStateException e) {
	e.printStackTrace();
} catch (IOException e) {
	e.printStackTrace();
}

mediaPlayer.start(); //再生開始
mediaPlayer.pause(); //一時停止
mediaPlayer.stop();  //停止

コントローラーを配置し実装する（未検証）

import android.os.Bundle;
import android.app.Activity;
import java.io.IOException;
import android.media.MediaPlayer;
import android.view.MotionEvent;
import android.widget.MediaController;

public class Mp3Activity extends Activity implements MediaController.MediaPlayerControl {

	private MediaPlayer mediaPlayer;
	private MediaController mediaController;

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

        String path = "再生するファイル";

        mediaPlayer = new MediaPlayer();
        mediaPlayer.setLooping(true);

        mediaController = new MediaController(this);
        mediaController.setAnchorView(findViewById(R.id.root));
        mediaController.setMediaPlayer(this);
        mediaController.setEnabled(true);

        try {
        	mediaPlayer.setDataSource(path);
        } catch (IllegalArgumentException e) {
        	e.printStackTrace();
        } catch (IllegalStateException e) {
        	e.printStackTrace();
        } catch (IOException e) {
        	e.printStackTrace();
        }

        try {
        	mediaPlayer.prepare();
        } catch (IllegalStateException e) {
        	e.printStackTrace();
        } catch (IOException e) {
        	e.printStackTrace();
        }

        //mediaPlayer.start(); //再生
        //mediaPlayer.pause(); //一時停止
        //mediaPlayer.stop();  //停止

    }

    @Override
    public void onResume() {
        super.onResume();
    }

    @Override
    public void onStop() {
    	super.onStop();
    	if (mediaPlayer != null) {
    		mediaController.hide();
        	mediaPlayer.stop();
        	mediaPlayer.release();
    	}
	}

    @Override
    public boolean onTouchEvent(MotionEvent event) {
    	mediaController.show();
        return super.onTouchEvent(event);
    }
    @Override
	public int getBufferPercentage() {
		return 0;
	}

	@Override
	public int getCurrentPosition() {
		return mediaPlayer.getCurrentPosition();
	}

	@Override
	public int getDuration() {
		return mediaPlayer.getDuration();
	}

	@Override
	public boolean isPlaying() {
		return mediaPlayer.isPlaying();
	}

	@Override
	public void pause() {
		mediaPlayer.pause();
	}

	@Override
	public void seekTo(int pos) {
		mediaPlayer.seekTo(pos);
	}

	@Override
	public void start() {
		mediaPlayer.start();
	}
}