Android音乐播放器

使用到Android的Actiivity和Service组件

播放音频的代码应该运行在服务中，定义一个播放服务MusicService，服务里定义play、stop、pause、continuePlay等方法

把这几个方法抽取成一个接口MusicInterface

定义一个中间人类，继承Binder，实现MusicInterface

操作按钮等使用Activity与用户交互

同时为了把服务所在进程变成服务进程，防止Activity销毁时依旧执行Service，需要使用Service启动的混合调用，即先使用startService()，然后使用bindService()方法。

原理：使用bindService()方法，启动service。在ServiceConnection的onServiceConnected()方法中返回一个iBinder对象，通过该对象可以操作音乐service中的播放音乐的方法。

播放服务

代码：

MainActivity:

1 importandroid.app.Activity;2 importandroid.content.ComponentName;3 importandroid.content.Intent;4 importandroid.content.ServiceConnection;5 importandroid.os.Bundle;6 importandroid.os.Handler;7 importandroid.os.IBinder;8 importandroid.view.View;9 importandroid.widget.SeekBar;10 importandroid.widget.SeekBar.OnSeekBarChangeListener;11

12 public class MainActivity extendsActivity {13

14 privateMusicInterface mi;15

16 static Handler handler = newHandler() {17 public voidhandleMessage(android.os.Message msg) {18 Bundle bundle =msg.getData();19 //取出消息携带的数据

20 int duration = bundle.getInt("duration");21 int currentPosition = bundle.getInt("currentPosition");22 //刷新播放进度

23 sb.setMax(duration);24 sb.setProgress(currentPosition);25 };26 };27

28

29

30 private staticSeekBar sb;31 @Override32 protected voidonCreate(Bundle savedInstanceState) {33 super.onCreate(savedInstanceState);34 setContentView(R.layout.activity_main);35 sb =(SeekBar) findViewById(R.id.sb);36 //给sb设置一个拖动侦听

37 sb.setOnSeekBarChangeListener(newOnSeekBarChangeListener() {38 //停止拖动时调用

39 @Override40 public voidonStopTrackingTouch(SeekBar seekBar) {41 //根据拖动进度，改变音乐播放进度

42 mi.seekTo(seekBar.getProgress());43 }44 //开始拖动时调用

45 @Override46 public voidonStartTrackingTouch(SeekBar seekBar) {47 //TODO Auto-generated method stub

48

49 }50 //拖动的时候不断调用

51 @Override52 public void onProgressChanged(SeekBar seekBar, intprogress,53 booleanfromUser) {54 //TODO Auto-generated method stub

55

56 }57 });58 Intent intent = new Intent(this, MusicService.class);59 //先start启动MusicService，再bind

60 startService(intent);61 MyServiceConn conn = newMyServiceConn();62 bindService(intent, conn, BIND_AUTO_CREATE);63 }64

65 class MyServiceConn implementsServiceConnection {66

67 @Override68 public voidonServiceConnected(ComponentName name, IBinder service) {69 mi =(MusicInterface) service;70 }71

72 @Override73 public voidonServiceDisconnected(ComponentName name) {74

75 }76

77 }78

79 public voidplay(View v) {80 mi.play();81 }82

83 public voidcontinuePlay(View v) {84 mi.continuePlay();85 }86

87 public voidpause(View v) {88 mi.pause();89 }90

91 public voidstop(View v) {92 mi.stop();93 }94 }

MusicService:

1 importjava.util.Timer;2 importjava.util.TimerTask;3

4 importandroid.app.Service;5 importandroid.content.Intent;6 importandroid.media.MediaPlayer;7 importandroid.media.MediaPlayer.OnPreparedListener;8 importandroid.os.Binder;9 importandroid.os.Bundle;10 importandroid.os.IBinder;11 importandroid.os.Message;12

13 public class MusicService extendsService {14 privateMediaPlayer player;15 privateTimer timer;16

17 @Override18 publicIBinder onBind(Intent intent) {19 //TODO Auto-generated method stub

20 return newMusicMiddleMan();21 }22

23 class MusicMiddleMan extends Binder implementsMusicInterface {24 public voidplay() {25 MusicService.this.play();26 }27

28 public voidpause() {29 MusicService.this.pause();30 }31

32 public voidcontinuePlay() {33 MusicService.this.continuePlay();34 }35

36 public voidstop() {37 MusicService.this.stop();38 }39

40 @Override41 public void seekTo(intprogress) {42 //TODO Auto-generated method stub

43 MusicService.this.seekTo(progress);44 }45

46

47 }48

49 @Override50 public voidonCreate() {51 //TODO Auto-generated method stub

52 super.onCreate();53 player = newMediaPlayer();54

55 }56

57 public voidplay() {58 System.out.println("播放");59 if (player == null) {60 player = newMediaPlayer();61 }62 player.reset();63 try{

//设置网络资源64 player.setDataSource("http://192.168.5.100:8080/HEYJUDE.mp3");65 //异步获取网络资源

66 player.prepareAsync();67 player.setOnPreparedListener(newOnPreparedListener() {68

69 @Override70 public voidonPrepared(MediaPlayer mp) {71 player.start();72 addTimer();73

74 }75 });76 } catch(Exception e) {77 e.printStackTrace();78 }79

80 }81

82 public voidcontinuePlay() {83 System.out.println("继续播放");84 player.start();85 }86

87 public voidpause() {88 System.out.println("暂停");89 player.pause();90 }91

92 public voidstop() {93 System.out.println("停止");94 player.stop();95 player.release();96 player = null;97 if (timer!=null) {98 timer.cancel();99 timer=null;100 }101 }102

103 public void seekTo(intprogress){104 player.seekTo(progress);105 }106

107 public voidaddTimer() {108 //播放进度需要不停的获取，不停的刷新进度条，使用计时器每1000毫秒获取一次播放进度109 //发消息至Handler，把播放进度放进Message对象中，在Handler中更新SeekBar的进度

110 if (timer == null) {111

112 timer = newTimer();113 timer.schedule(newTimerTask() {114

115 @Override116 public voidrun() {117 //获取到歌曲总时长

118 int duration =player.getDuration();119 //获取歌曲当前进度

120 int currentPosition =player.getCurrentPosition();121 Message msg =MainActivity.handler.obtainMessage();122 Bundle bundle = newBundle();123 bundle.putInt("duration", duration);124 bundle.putInt("currentPosition", currentPosition);125 msg.setData(bundle);126 MainActivity.handler.sendMessage(msg);127

128 }129 }, 5, 1000);130 }131

132 }133

134 }

把MusicControl类抽取出来为接口，这样可以在MainActivity中只可以访问接口的方法，MusicControl类中的其他方法不被方法

MusicInterface:

1 public interfaceMusicInterface {2

3 voidplay();4 voidcontinuePlay();5 voidstop();6 voidpause();7 void seekTo(intprogress);8

9 }