basic play mp3 part 2

package com.example.viraj.mediaplayerapp;
import android.media.MediaPlayer;import android.support.v7.app.AppCompatActivity;import android.os.Bundle;import android.view.View;import android.widget.Button;import android.widget.Toast;
//import static com.example.viraj.mediaplayerapp.R.raw.ashique;

public class MainActivity extends AppCompatActivity {
    private MediaPlayer mediaPlayer;
    private Button playbutton;

    @Override    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        mediaPlayer = new MediaPlayer();
        mediaPlayer = MediaPlayer.create(MainActivity.this,R.raw.mercy);

       //set on completion method-----------------        mediaPlayer.setOnCompletionListener(new MediaPlayer.OnCompletionListener() {
    @Override    public void onCompletion(MediaPlayer mediaPlayer_mp) {
        int duration =mediaPlayer_mp.getDuration();
        String mduration=String.valueOf(duration/1000);
        Toast.makeText(getApplicationContext(),"Duration"+mduration,Toast.LENGTH_LONG).show();
    }
});

        //----------------------------
        playbutton = (Button) findViewById(R.id.MusicPlay);
        playbutton.setOnClickListener(new View.OnClickListener() {
            @Override            public void onClick(View view) {
                if (mediaPlayer.isPlaying()) {
                    //stop music and give option                    pausemusic();
                }
                else                {
                    startmusic();
                }
            }
        });

    }
    //create method in side of our class    public void pausemusic() {
        if (mediaPlayer != null)
            mediaPlayer.pause();
        playbutton.setText("PLAY MUSIC");
    }

    public void startmusic()

    {
        if (mediaPlayer != null) {
            mediaPlayer.start();
            playbutton.setText("PAUSE MUSIC");
        }

    }//memory consume karta he iss liye    @Override    protected void onDestroy() {
       if (mediaPlayer!=null && mediaPlayer.isPlaying())
       {
           mediaPlayer.stop();
           mediaPlayer.release();
           mediaPlayer=null;
       }
        super.onDestroy();
    }
}