简单Android音乐播放器

    通过一段时间的学习，我制作了一个简单的音乐播放器，可以实现一些音乐功能，界面如下图所示：

1、界面的制作

2、页面制作完成后，则在MainActivity中将控件声明和初始化

private TextView musicStatus, musicTime, musicTotal;
    private SeekBar seekBar;
    private Button btnPlayOrPause, btnStop, btnQuit, btnNext, btnLast;


musicTime = (TextView) findViewById(R.id.MusicTime);
        musicTotal = (TextView) findViewById(R.id.MusicTotal);
        seekBar = (SeekBar) findViewById(R.id.MusicSeekBar);
        btnPlayOrPause = (Button) findViewById(R.id.BtnPlayorPause);
        btnStop = (Button) findViewById(R.id.BtnStop);
        btnQuit = (Button) findViewById(R.id.BtnQuit);
        btnLast = (Button) findViewById(R.id.BtnPre);
        btnNext = (Button) findViewById(R.id.BtnNext);
        musicStatus = (TextView) findViewById(R.id.MusicStatus);

3、本音乐播放器运用server来进行控制，以实现后台播放。所以，之后新建MusicService类，用来继承server。并在MusicService中定义MediaPlayer用来控制音乐的播放。
定义和使用MediaPlayer：

public MusicService() {
        mediaPlayer = new MediaPlayer();
        try {
        	musicIndex = 0;
            mediaPlayer.setDataSource(musicDir[musicIndex]);
            mediaPlayer.prepare();
            mediaPlayer.setLooping(false);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

音乐播放的停止和开始等功能（上一首和下一首代码类似）：

 public void playOrPause() {
        if (mediaPlayer.isPlaying()) {
            mediaPlayer.pause();
        } else {
            mediaPlayer.start();
        }
    }

    public void stop() {
        if (mediaPlayer != null) {
            mediaPlayer.stop();
            try {
                mediaPlayer.reset();
                mediaPlayer.setDataSource(musicDir[musicIndex]);
                mediaPlayer.prepare();
                mediaPlayer.seekTo(0);
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    }

    //下一首  
    public void nextMusic() {  
        if(mediaPlayer != null && musicIndex < 2) {  
        	mediaPlayer.stop();  
            try {  
            	mediaPlayer.reset();  
            	mediaPlayer.setDataSource(musicDir[musicIndex+1]);  
                musicIndex++;  
                mediaPlayer.prepare();  
                mediaPlayer.seekTo(0);  
                mediaPlayer.start();  
            } catch (Exception e) {  
               
                e.printStackTrace();  
            }  
        }else {  
            Toast.makeText(this, "没有更多歌曲啦", Toast.LENGTH_SHORT).show();  
        }  
    }  

4、Activity 和 Service 的通信

 public MyBinder binder = new MyBinder();
    public class MyBinder extends Binder {
        MusicService getService() {
            return MusicService.this;
        }
    }

//  在Activity中调用 bindService 保持与 Service 的通信
    private void bindServiceConnection() {
        Intent intent = new Intent(MainActivity.this, MusicService.class);
        startService(intent);
        bindService(intent, serviceConnection, Context.BIND_AUTO_CREATE);
    }

    //  回调onServiceConnected 函数，通过IBinder 获取 Service对象，实现Activity与 Service的绑定
    private ServiceConnection serviceConnection = new ServiceConnection() {
        @Override
        public void onServiceConnected(ComponentName name, IBinder service) {
            musicService = ((MusicService.MyBinder) (service)).getService();
            Log.i("musicService", musicService + "");
            musicTotal.setText(time.format(musicService.mediaPlayer.getDuration()));
           //musicService = ((MusicService.MyBinder)service).getService();
        }
        @Override
        public void onServiceDisconnected(ComponentName name) {
            musicService = null;
        }
    };

5、handler的使用。
因为Android的UI更新只能在主线程中，所以我们用handler来更新UI

public Handler handler = new Handler();
    public Runnable runnable = new Runnable() {
        @Override
        public void run() {
            musicTime.setText(time.format(musicService.mediaPlayer.getCurrentPosition()));
            seekBar.setProgress(musicService.mediaPlayer.getCurrentPosition());
            seekBar.setMax(musicService.mediaPlayer.getDuration());
            musicTotal.setText(time.format(musicService.mediaPlayer.getDuration()));
            handler.postDelayed(runnable, 200);

        }
    };

6、各个控件的监听事件

 seekBar.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener() {
            @Override
            public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) {
                if (fromUser == true) {
                    musicService.mediaPlayer.seekTo(progress);
                }
            }

            @Override
            public void onStartTrackingTouch(SeekBar seekBar) {

            }

            @Override
            public void onStopTrackingTouch(SeekBar seekBar) {

            }
        });

    }

btnPlayOrPause.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (musicService.mediaPlayer != null) {
                    seekBar.setProgress(musicService.mediaPlayer.getCurrentPosition());
                    seekBar.setMax(musicService.mediaPlayer.getDuration());
                }
                //  由tag的变换来控制事件的调用
                if (musicService.tag != true) {
                    btnPlayOrPause.setText("PAUSE");
                    musicStatus.setText("Playing");
                    musicService.playOrPause();
                    musicService.tag = true;

                    if (tag1 == false) {
                        animator.start();
                        tag1 = true;
                    } else {
                       imageView.clearAnimation(); //animator.resume();
                    }
                } else {
                    btnPlayOrPause.setText("PLAY");
                    musicStatus.setText("Paused");
                    musicService.playOrPause();
                    imageView.clearAnimation(); //animator.pause();
                    musicService.tag = false;
                }
                if (tag2 == false) {
                    handler.post(runnable);
                    tag2 = true;
                }
            }
        });

各个控件的监听大同小异，我就一一列举，最主要的是下面这个监听

//  停止服务时，必须解除绑定，写入btnQuit按钮中
        btnQuit.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                handler.removeCallbacks(runnable);
                unbindService(serviceConnection);
                Intent intent = new Intent(MainActivity.this, MusicService.class);
                stopService(intent);
                try {
                    MainActivity.this.finish();
                } catch (Exception e) {

                }
            }
        });

7、从sdcard中读取音乐文件， 有两种不同的方式

private String[] musicDir = new String[]{"/mnt/sdcard/LOST.DIR/a1.mp3","/mnt/sdcard/LOST.DIR/b2.mp3"}; //虚拟机上的目录
   
   // private String[] musicDir = new String[]{Environment.getExternalStorageDirectory().getAbsolutePath()+"/music/Honor.mp3",
    //	Environment.getExternalStorageDirectory().getAbsolutePath()+"/music/Jive_Cool.mp3"};读取外部储存卡（手机的目录）

8、大概代码和流程就是这些了，制作比较简单。下面是下载的地址：

下载地址：点击打开链接