功能：播放，暂停，上一首，下一首
部分demo：
MainActivity：
public class MainActivity extends Activity implements OnClickListener
{
// 获取界面中显示歌曲标题、作者文本框
TextView title, author;
// 播放/暂停、停止按钮
ImageButton play, stop;
//上一首，下一首
ImageButton pre, next;
ImageView cover;
ActivityReceiver activityReceiver;
public static final String CTL_ACTION =
"org.crazyit.action.CTL_ACTION";
public static final String UPDATE_ACTION =
"org.crazyit.action.UPDATE_ACTION";
// 定义音乐的播放状态，1代表没有播放;2代表正在播放;3代表暂停
int status = 1;
String[] titleStrs = new String[] { "无羁", "莲花坞", "荒城渡" };
String[] authorStrs = new String[] { "王一博", "林海", "周深" };
Integer[] covers = new Integer[] { R.drawable.unrestrained, R.drawable.lotus,
R.drawable.barrencity};
@Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// 获取程序界面界面中的两个按钮
play = (ImageButton) this.findViewById(R.id.play);
stop = (ImageButton) this.findViewById(R.id.stop);
title = (TextView) findViewById(R.id.title);
author = (TextView) findViewById(R.id.author);
cover = findViewById(R.id.cover);
pre = this.findViewById(R.id.pre);
next = this.findViewById(R.id.next);
// 为两个按钮的单击事件添加监听器
play.setOnClickListener(this);
stop.setOnClickListener(this);
// 为上一首、下一首的单击事件添加监听器
pre.setOnClickListener(this);
next.setOnClickListener(this);
activityReceiver = new ActivityReceiver();
// 创建IntentFilter
IntentFilter filter = new IntentFilter();
// 指定BroadcastReceiver监听的Action
filter.addAction(UPDATE_ACTION);
// 注册BroadcastReceiver
registerReceiver(activityReceiver, filter);
Intent intent = new Intent(this, MusicService.class);
// 启动后台Service
startService(intent);
}
// 自定义的BroadcastReceiver，负责监听从Service传回来的广播
public class ActivityReceiver extends BroadcastReceiver
{
@Override
public void onReceive(Context context, Intent intent)
{
// 获取Intent中的update消息，update代表播放状态
int update = intent.getIntExtra("update", -1);
// 获取Intent中的current消息，current代表当前正在播放的歌曲
int current = intent.getIntExtra("current", -1);
if (current >= 0)
{
title.setText(titleStrs[current]);
author.setText(authorStrs[current]);
cover.setImageResource(covers[current]);
}
switch (update)
{
case 1:
play.setImageResource(R.drawable.play);
status = 1;
break;
// 控制系统进入播放状态
case 2:
// 播放状态下设置使用暂停图标
play.setImageResource(R.drawable.pause);
// 设置当前状态
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status = 2;
break;
// 控制系统进入暂停状态
case 3:
// 暂停状态下设置使用播放图标
play.setImageResource(R.drawable.play);
// 设置当前状态
status = 3;
break;
}
}
}
@Override
public void onClick(View source)
{
// 创建Intent
Intent intent = new Intent("org.crazyit.action.CTL_ACTION");
switch (source.getId())
{
// 按下播放/暂停按钮
case R.id.play:
intent.putExtra("control", 1);
break;
// 按下停止按钮
case R.id.stop:
intent.putExtra("control", 2);
break;
case R.id.pre:
intent.putExtra("control",3);
case R.id.next:
intent.putExtra("control",4);
}
// 发送广播，将被Service组件中的BroadcastReceiver接收到
sendBroadcast(intent);
}
}
MusicService：
public class MusicService extends Service
{
MyReceiver serviceReceiver;
AssetManager am;
String[] musics = new String[] { "unrestrained.mp3" +
"", "lotus.mp3",
"barrencity.mp3"};
MediaPlayer mPlayer;
// 当前的状态，1代表没有播放;2代表正在播放;3代表暂停
int status = 1;
// 记录当前正在播放的音乐
int current = 0;
@Override
public IBinder onBind(Intent intent)
{
return null;
}
@Override
public void onCreate()
{
super.onCreate();
am = getAssets();
// 创建BroadcastReceiver
serviceReceiver = new MyReceiver();
// 创建IntentFilter
IntentFilter filter = new IntentFilter();
filter.addAction(MainActivity.CTL_ACTION);
registerReceiver(serviceReceiver, filter);
// 创建MediaPlayer
mPlayer = new MediaPlayer();
// 为MediaPlayer播放完成事件绑定监听器
mPlayer.setOnCompletionListener(new OnCompletionListener() // ①
{
@Override
public void onCompletion(MediaPlayer mp)
{
current++;
if (current >= 3)
{
current = 0;
}
//发送广播通知Activity更改文本框
Intent sendIntent = new Intent(MainActivity.UPDATE_ACTION);
sendIntent.putExtra("current", current);
// 发送广播，将被Activity组件中的BroadcastReceiver接收到
sendBroadcast(sendIntent);
// 准备并播放音乐
prepareAndPlay(musics[current]);
}
});
}
public class MyReceiver extends BroadcastReceiver
{
@Override
public void onReceive(final Context context, Intent intent)
{
int control = intent.getIntExtra("control", -1);
switch (control)
{
// 播放或暂停
case 1:
// 原来处于没有播放状态
if (status == 1)
{
// 准备并播放音乐
prepareAndPlay(musics[current]);
status = 2;
}
// 原来处于播放状态
else if (status == 2)
{
// 暂停
mPlayer.pause();
// 改变为暂停状态
status = 3;
}
// 原来处于暂停状态
else if (status == 3)
{
// 播放
mPlayer.start();
// 改变状态
status = 2;
}
break;
// 停止声音
case 2:
// 如果原来正在播放或暂停
if (status == 2 || status == 3)
{
// 停止播放
mPlayer.stop();
status = 1;
}
case 3:
current--;
if(current < 0)
current = 0;
prepareAndPlay(musics[current]);
case 4:
current++;
if(current > musics.length-1)
current = 0;
prepareAndPlay(musics[current]);
}
// 广播通知Activity更改图标、文本框
Intent sendIntent = new Intent(MainActivity.UPDATE_ACTION);
sendIntent.putExtra("update", status);
sendIntent.putExtra("current", current);
// 发送广播，将被Activity组件中的BroadcastReceiver接收到
sendBroadcast(sendIntent);
}
}
private void prepareAndPlay(String music)
{
try
{
// 打开指定音乐文件
AssetFileDescriptor afd = am.openFd(music);
mPlayer.reset();
// 使用MediaPlayer加载指定的声音文件。
mPlayer.setDataSource(afd.getFileDescriptor(),
afd.getStartOffset(), afd.getLength());
// 准备声音
mPlayer.prepare();
// 播放
mPlayer.start();
}
catch (IOException e)
{
e.printStackTrace();
}
}
}