Play foreground and background music using SoundPool and MediaPlayer

Merge the previous exercises "A simple exercise to play MIDI audio using MediaPlayer" and "Play audio resources using SoundPool", to implement a app to play audio using both MediaPlayer and SoundPool

LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
   android:orientation="vertical"
   android:layout_width="fill_parent"
   android:layout_height="fill_parent"
   
TextView 
   android:layout_width="fill_parent"
   android:layout_height="wrap_content"
   android:text="@string/hello"
   
Button
   android:id="@+id/playmediaplayer" 
   android:layout_width="fill_parent"
   android:layout_height="wrap_content"
   android:text="- PLAY MediaPlayer -"   /

Button
   android:id="@+id/pausemediaplayer" 
   android:layout_width="fill_parent"
   android:layout_height="wrap_content"
   android:text="- PAUSE MediaPlayer -"
   /
Button
   android:id="@+id/playsoundpool" 
   android:layout_width="fill_parent"
   android:layout_height="wrap_content"
   android:text="- PLAY SoundPool -"
   /
Button
   android:id="@+id/pausesoundpool" 
   android:layout_width="fill_parent"
   android:layout_height="wrap_content"
   android:text="- PAUSE SoundPool -"

LinearLayout

import java.util.HashMap;

import android.app.Activity;
import android.content.Context;
import android.media.AudioManager;
import android.media.MediaPlayer;
import android.media.SoundPool;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;

public class AndroidAudioPlayer extends Activity {

MediaPlayer mediaPlayer;
SoundPool soundPool;
HashMap soundPoolMap;
int soundID = 1;

/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);

mediaPlayer = MediaPlayer.create(this, R.raw.midi_sound);
soundPool = new SoundPool(4, AudioManager.STREAM_MUSIC, 100);
soundPoolMap = new HashMap();
//soundPoolMap.put(soundID, soundPool.load(this, R.raw.midi_sound, 1));
soundPoolMap.put(soundID, soundPool.load(this, R.raw.fallbackring, 1));

Button buttonPlayMediaPlayer = (Button)findViewById(R.id.playmediaplayer);
Button buttonPauseMediaPlayer = (Button)findViewById(R.id.pausemediaplayer);
Button buttonPlaySoundPool = (Button)findViewById(R.id.playsoundpool);
Button buttonPauseSoundPool = (Button)findViewById(R.id.pausesoundpool);
buttonPlayMediaPlayer.setOnClickListener(buttonPlayMediaPlayerOnClickListener);
buttonPauseMediaPlayer.setOnClickListener(buttonPauseMediaPlayerOnClickListener);
buttonPlaySoundPool.setOnClickListener(buttonPlaySoundPoolOnClickListener);
buttonPauseSoundPool.setOnClickListener(buttonPauseSoundPoolOnClickListener);
}

Button.OnClickListener buttonPlayMediaPlayerOnClickListener
= new Button.OnClickListener(){
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
if(!mediaPlayer.isPlaying()){
mediaPlayer.start();
Toast.makeText(AndroidAudioPlayer.this,
"soundPool.pause()",
Toast.LENGTH_LONG).show();
}
}
};

Button.OnClickListener buttonPauseMediaPlayerOnClickListener
= new Button.OnClickListener(){
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
if(mediaPlayer.isPlaying()){
mediaPlayer.pause();
Toast.makeText(AndroidAudioPlayer.this,
"soundPool.pause()",
Toast.LENGTH_LONG).show();
}
}
};

Button.OnClickListener buttonPlaySoundPoolOnClickListener
= new Button.OnClickListener(){
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
AudioManager audioManager = (AudioManager)getSystemService(Context.AUDIO_SERVICE);
float curVolume = audioManager.getStreamVolume(AudioManager.STREAM_MUSIC);
float maxVolume = audioManager.getStreamMaxVolume(AudioManager.STREAM_MUSIC);
float leftVolume = curVolume/maxVolume;
float rightVolume = curVolume/maxVolume;
int priority = 1;
int no_loop = 0;
float normal_playback_rate = 1f;
soundPool.play(soundID, leftVolume, rightVolume, priority, no_loop, normal_playback_rate);

Toast.makeText(AndroidAudioPlayer.this,
"soundPool.play()",
Toast.LENGTH_LONG).show();
}
};

Button.OnClickListener buttonPauseSoundPoolOnClickListener
= new Button.OnClickListener(){
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
soundPool.pause(soundID);
Toast.makeText(AndroidAudioPlayer.this,
"soundPool.pause()",
Toast.LENGTH_LONG).show();
}
};

}