Android : Android other button music enabled

i have 3 buttons my app. i click any button for music and When I press another button while playing music currently playing music I want to shut up

help please

    public class MainActivity extends Activity {

MediaPlayer sesbuton,sesbuton2,sesbuton3;
Button button1,button2,button3;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);


    sesbuton=MediaPlayer.create(MainActivity.this, R.raw.butonses);
    sesbuton2=MediaPlayer.create(MainActivity.this, R.raw.kanarya);
    sesbuton3=MediaPlayer.create(MainActivity.this, R.raw.ordek);



    button1=(Button) findViewById(R.id.button1);
    button2=(Button) findViewById(R.id.button2);
    button3=(Button) findViewById(R.id.button3);

and ı used onClick method button1.setOnClickListener(new View.OnClickListener() {

        @Override
        public void onClick(View v) {
            // TODO Auto-generated method stub

            sesbuton.start();

        }
    });

    button2.setOnClickListener(new View.OnClickListener() {

        @Override
        public void onClick(View v) {
            // TODO Auto-generated method stub

            sesbuton2.start();  
        }
    });

    button3.setOnClickListener(new View.OnClickListener() {

        @Override
        public void onClick(View v) {
            // TODO Auto-generated method stub
            sesbuton3.start();  
        }
    });