Music-Android : Selection of music through Spinner and play

What i want to do is to add a spinner and a button, in spinner 2 songs are placed when i selected a song it plays and same as for other one but when i run this code it will do nothing just display a spinner and button and i only select a song and when i clicked a play button it do no respond.

import android.media.MediaPlayer;    
import android.support.v7.app.ActionBarActivity;    
import android.os.Bundle;    
import android.view.Menu;    
import android.view.MenuItem;    
import android.view.View;    
import android.widget.AdapterView;    
import android.widget.ArrayAdapter;    
import android.widget.Button;    
import android.widget.Spinner;    
import android.widget.Toast;    


public class MainActivity extends ActionBarActivity {    
public int soundSelection;    
MediaPlayer mp;    
Button btn;    
@Override    
protected void onCreate(Bundle savedInstanceState) {    
    super.onCreate(savedInstanceState);    
    setContentView(R.layout.activity_main);    
    Spinner spinner = (Spinner) findViewById(R.id.spinner1);    
    btn=(Button)findViewById(R.id.button1);    
    ArrayAdapter<CharSequence> adapter = ArrayAdapter.createFromResource(this, R.array.soundEntries, android.R.layout.simple_spinner_item);    
    adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);    
    spinner.setAdapter(adapter);    
    btn.setOnClickListener(new View.OnClickListener() {    
        @Override    
        public void onClick(View v) {    
            switch (soundSelection) {    
                case 1:    
                   if (mp != null && mp.isPlaying())    

                    mp = MediaPlayer.create(MainActivity.this, R.raw.bewafa);    
                    mp.start();    
                    mp.setVolume(100,100);    
                    mp.setLooping(true);    
                    Toast t = Toast.makeText(MainActivity.this,"bewafa",Toast.LENGTH_LONG);
                    t.show();    
                    break;    
                case 2:    
                    // if(mp.isPlaying())    

                    mp = MediaPlayer.create(getApplicationContext(), R.raw.dildobaa);    
                    mp.start();    
                    Toast th = Toast.makeText(getApplicationContext(), "dildobaa", Toast.LENGTH_LONG);    
                    th.show();    
                    break;

            }   
        }   
    });    
}    






/*Spinner Functions*/
public void onItemSelected(AdapterView<?> parent, View view, int pos, long id)     
    soundSelection=(Integer)parent.getItemAtPosition(pos);    
}    

public void onNothingSelected(AdapterView<?> parent) {    
    // Do nothing.    
}    

@Override    
public boolean onCreateOptionsMenu(Menu menu) {    
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.menu_main, menu);    
    return true;    
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {    
    // Handle action bar item clicks here. The action bar will    
    // automatically handle clicks on the Home/Up button, so long    
    // as you specify a parent activity in AndroidManifest.xml.    
    int id = item.getItemId();    

    //noinspection SimplifiableIfStatement    
    if (id == R.id.action_settings) {    
        return true;    
    }    

    return super.onOptionsItemSelected(item);    
}    

}