音樂播放器

import android.Manifest;
import android.content.ComponentName;
import android.content.Intent;
import android.content.ServiceConnection;
import android.content.pm.PackageManager;
import android.os.Bundle;
import android.os.Handler;
import android.os.IBinder;
import android.os.Message;
import android.support.v4.app.ActivityCompat;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.Button;
import android.widget.SeekBar;

public class MainActivity extends AppCompatActivity {
    private Button btn1;
    private Button btn2;
    private Button btn3;
    private Button btn4;
    private static SeekBar sb;
    private IService iService;
    private MusicConn conn;
    public static Handler handler = new Handler(){
        @Override
        public void handleMessage(Message msg) {
            Bundle bundle = msg.getData();
            int duration = bundle.getInt("duration");
            int position = bundle.getInt("position");
            sb.setMax(duration);
            sb.setProgress(position);
        }
    };

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        btn1 = (Button) findViewById(R.id.btn1);
        btn2 = (Button) findViewById(R.id.btn2);
        btn3 = (Button) findViewById(R.id.btn3);
        btn4 = (Button) findViewById(R.id.btn4);
        sb = (SeekBar) findViewById(R.id.sb);
        //
        Intent intent = new Intent(this, MusicService.class);
        startService(intent);
        conn = new MusicConn();
        bindService(intent, conn, BIND_AUTO_CREATE);
        //
        btn1.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                getPermissons();
                iService.callPlay();
            }
        });
        btn2.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                iService.callStop();
            }
        });
        btn3.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                iService.callPause();
            }
        });
        btn4.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                iService.callContinueMusic();
            }
        });
        sb.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener() {
            @Override
            public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) {}
            @Override
            public void onStartTrackingTouch(SeekBar seekBar) {}
            @Override
            public void onStopTrackingTouch(SeekBar seekBar) {
                iService.callSeekTo(seekBar.getProgress());
            }
        });
    }
    private void getPermissons() {
        int code = ActivityCompat.checkSelfPermission(
                MainActivity.this,
                Manifest.permission.WRITE_EXTERNAL_STORAGE);
        if (code != PackageManager.PERMISSION_GRANTED) {
            ActivityCompat.requestPermissions(MainActivity.this,new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE},1);
        }
        //播放網絡歌曲 未請求權限
//        code = ActivityCompat.checkSelfPermission(
//                MainActivity.this,
//                Manifest.permission.INTERNET);
//        if (code != PackageManager.PERMISSION_GRANTED) {
//            ActivityCompat.requestPermissions(MainActivity.this,new String[]{Manifest.permission.INTERNET},1);
//        }
    }

    @Override
    protected void onDestroy() {
        unbindService(conn);
        super.onDestroy();
    }

    class MusicConn implements ServiceConnection {
        @Override
        public void onServiceConnected(ComponentName name, IBinder service) {
            iService = (IService) service;
        }

        @Override
        public void onServiceDisconnected(ComponentName name) {
        }
    }
}

import android.app.Service;
import android.content.Intent;
import android.media.MediaPlayer;
import android.os.Binder;
import android.os.Bundle;
import android.os.IBinder;
import android.os.Message;
import android.util.Log;

import java.io.IOException;
import java.util.Timer;
import java.util.TimerTask;

import static android.content.ContentValues.TAG;

public class MusicService extends Service {
    private MediaPlayer mediaPlayer;
    private Timer timer = null;
    private TimerTask task = null;
    public MusicService() {}
    @Override
    public void onCreate() {
        //初始化mediaplayer
        mediaPlayer = new MediaPlayer();
        //播放結束後，取消定時器
        mediaPlayer.setOnCompletionListener(new MediaPlayer.OnCompletionListener() {
            @Override
            public void onCompletion(MediaPlayer mp) {
                task.cancel();
                timer.cancel();
            }
        });
        super.onCreate();
    }

    @Override
    public IBinder onBind(Intent intent) {
        return new MusicBinder();
    }
    private void play() {
        try {
            mediaPlayer.reset();
            //播放本地音樂
//            mediaPlayer.setDataSource("/storage/emulated/0/fly.mp3");
//            mediaPlayer.prepare();

            //播放網絡音樂，拖放會有問題
            mediaPlayer.setDataSource("http://123.56.111.226:8080/boat.mp3");
            mediaPlayer.prepareAsync();
            mediaPlayer.setOnPreparedListener(new MediaPlayer.OnPreparedListener() {
                @Override
                public void onPrepared(MediaPlayer mp) {
                    mediaPlayer.start();
                }
            });
        } catch (IOException e) {
            e.printStackTrace();
        }
        mediaPlayer.start();
        refereshSeekBar();
    }

    private void refereshSeekBar() {
        timer = new Timer();
        task = new TimerTask() {
            @Override
            public void run() {
                int position = mediaPlayer.getCurrentPosition();
                int duration = mediaPlayer.getDuration();
                Message msg = new Message();
                Bundle data = new Bundle();
                data.putInt("duration",duration);
                data.putInt("position",position);
                msg.setData(data);
                MainActivity.handler.sendMessage(msg);
            }
        };
        timer.schedule(task,100,1000);
    }

    public void seekTo(int position) {
        mediaPlayer.seekTo(position);
    }

    private void stop(){
        mediaPlayer.stop();
        Log.i(TAG, "stop: ");
    }
    private void continueMusic() {
        mediaPlayer.start();
    }

    private void pause() {
        mediaPlayer.pause();
    }
    //------------------------------------------------------
    class MusicBinder extends Binder implements IService{
        @Override
        public void callPlay() {
            play();
        }

        @Override
        public void callStop() {
            stop();
        }

        @Override
        public void callPause() {
            pause();
        }

        @Override
        public void callContinueMusic() {
            continueMusic();
        }

        @Override
        public void callSeekTo(int position) {
            seekTo(position);
        }
    }

}

public interface IService {
    void callPlay();
    void callStop();
    void callPause();
    void callContinueMusic();
    void callSeekTo(int position);
}