Android之SoundPool背景音乐，MediaPlayer播放背景音乐

public class SimpleActivity extends AppCompatActivity {
SoundPool sp;
HashMap<Integer, Integer> hm;
int currStreanId;
@Bind(R.id.button2)
Button button2;
@Bind(R.id.button3)
Button button3;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_simple);
ButterKnife.bind(this);

initSoundPool();

}

@OnClick({R.id.button2, R.id.button3})
public void onClick(View view) {
switch (view.getId()) {
case R.id.button2:
playSoud(1,-1);//播放次数，-1表示无限重复，0表示一次，1表示两次，以此类推。
break;
case R.id.button3:
sp.stop(currStreanId);
break;
}
}

/**
* 由于SoundPool只适合播放不大于7秒的文件，实际游戏开发中采用的是MediaPlay来播放背景音乐
*
*
*/

//初始化声音池
private void initSoundPool() {
sp = new SoundPool(4, AudioManager.STREAM_MUSIC, 0);
hm = new HashMap<>();
hm.put(1, sp.load(this, R.raw.siml, 1));

}
//播放声音的方法
private void playSoud(int sound, int loop) {

AudioManager am = (AudioManager) this.getSystemService(Context.AUDIO_SERVICE);//获取当前音量
float streamVolumeCurrent = am.getStreamVolume(AudioManager.STREAM_MUSIC);
float streamVolumeMax = am.getStreamMaxVolume(AudioManager.STREAM_MUSIC);//计算获得系统最大音量
float volume = streamVolumeCurrent/streamVolumeMax;//计算得到的播放音量
currStreanId = sp.play(hm.get(sound), volume, volume, 1, loop, 1.0f);
}
}

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context="com.yang.yin.yinyangapplication.SimpleActivity">

<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/playmu"
android:id="@+id/button2"
android:layout_alignParentTop="true"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:layout_marginTop="130dp" />

<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/stopmu"
android:id="@+id/button3"
android:layout_below="@+id/button2"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true" />
</RelativeLayout>

public class SimpleActivity extends AppCompatActivity {

@Bind(R.id.button2)
Button button2;
@Bind(R.id.button3)
Button button3;
@Bind(R.id.button4)
Button button4;
@Bind(R.id.button5)
Button button5;
@Bind(R.id.button6)
Button button6;

MediaPlayer mp;
AudioManager am;

private int maxVolume;
private int currVolume;
private  int stepVolume;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_simple);
ButterKnife.bind(this);

mp = MediaPlayer.create(this, R.raw.siml);

am = (AudioManager) this.getSystemService(AUDIO_SERVICE);
maxVolume = am.getStreamMaxVolume(AudioManager.STREAM_MUSIC);
stepVolume = maxVolume/6;

}

@OnClick({R.id.button2, R.id.button3, R.id.button4, R.id.button5, R.id.button6})
public void onClick(View view) {
switch (view.getId()) {
case R.id.button2:
mp.start();
break;
case R.id.button3:
mp.pause();
break;
case R.id.button4:
mp.stop();
try {
mp.prepare();//进入准备状态
} catch (IOException e) {
e.printStackTrace();
}

break;
case R.id.button5:
currVolume = am.getStreamVolume(AudioManager.STREAM_MUSIC);
int tmpVolume = currVolume + stepVolume;//临时音量
currVolume = tmpVolume<maxVolume?tmpVolume:maxVolume;
am.setStreamVolume(AudioManager.STREAM_MUSIC,currVolume,AudioManager.FLAG_PLAY_SOUND);
break;
case R.id.button6:
currVolume = am.getStreamVolume(AudioManager.STREAM_MUSIC);
int tmVolume = currVolume - stepVolume;//临时音量
currVolume = tmVolume<0?tmVolume:0;
am.setStreamVolume(AudioManager.STREAM_MUSIC,currVolume,AudioManager.FLAG_PLAY_SOUND);
break;
}
}
}

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context="com.yang.yin.yinyangapplication.SimpleActivity">

<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/playmu"
android:id="@+id/button2"
android:layout_alignParentTop="true"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:layout_marginTop="130dp" />

<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/stopmu"
android:id="@+id/button3"
android:layout_below="@+id/button2"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true" />

<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/closemu"
android:id="@+id/button4"
android:layout_centerVertical="true"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true" />

<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/add_sound"
android:id="@+id/button5"
android:layout_below="@+id/button4"
android:layout_alignRight="@+id/button3"
android:layout_alignEnd="@+id/button3"
android:layout_marginTop="25dp" />

<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/small_sound"
android:id="@+id/button6"
android:layout_below="@+id/button5"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:layout_marginTop="24dp" />
</RelativeLayout>