Music播放器

1.开启服务实现销毁Activity后能实现继续播放

package text.baidumusic;

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.support.annotation.Nullable;

import java.util.Timer;
import java.util.TimerTask;

/**
 * Created by liuwei on 7/8/17.
 */

public class MusicService extends Service {
    private MediaPlayer mediaPlayer;
    private class myBinder extends Binder implements myMusicService{
        @Override
        public void startPlay() {
            playMusic();
        }

        @Override
        public void pausePlay() {
            pauseMusic();
        }

        @Override
        public void stopPlay() {
            stopMusic();
        }
        @Override
        public void repaly() {
            replayMusic();
        }

        @Override
        public void seekTo(int position) {
            seekTo(position);
        }
    }
    @Nullable
    @Override
    public IBinder onBind(Intent intent) {
        return new myBinder() ;
    }
    public void playMusic(){
        System.out.println("音乐播放");
        try {
            mediaPlayer.setDataSource("/mnt/sdcard/1.mp3");
            mediaPlayer.prepare();
            mediaPlayer.start();
            updateSeekBar();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    private void updateSeekBar() {
        //获取当前播放总进度
        final int duration=mediaPlayer.getDuration();
        //使用timer
        Timer timer=new Timer();
        TimerTask task=new TimerTask() {
            @Override
            public void run() {
                int currentPosition=mediaPlayer.getCurrentPosition();
                Message msg=Message.obtain();
                Bundle bundle=new Bundle();
                bundle.putInt("duration",duration);
                bundle.putInt("currentPosition",currentPosition);
                msg.setData(bundle);
                MainActivity.handler.sendMessage(msg);
            }
        };
        timer.schedule(task,100,1000);
    }

    public void replayMusic(){
        mediaPlayer.start();
    }
    public void pauseMusic(){
        System.out.println("音乐暂停");
        mediaPlayer.pause();
    }
    public void stopMusic(){
        System.out.println("音乐停止");
        mediaPlayer.stop();
        onDestroy();
        onCreate();
    }
    public void seekTo(int position){
        mediaPlayer.seekTo(position);
    }
    @Override
    public void onCreate() {
        System.out.println("音乐服务创建");
        mediaPlayer = new MediaPlayer();
        super.onCreate();
    }

    @Override
    public void onDestroy() {
        System.out.println("音乐服务销毁");
        super.onDestroy();
    }
}

2.通过暴露接口的方法实现在活动中操作服务

public interface myMusicService {
    public void startPlay();
    public void pausePlay();
    public void stopPlay();
    public void repaly();
    public void seekTo(int position);
}

3.对music音乐通过开启绑定服务的方式进行播放，暂停，继续，停止操作

package text.baidumusic;

import android.Manifest;
import android.content.ComponentName;
import android.content.Intent;
import android.content.ServiceConnection;
import android.content.pm.PackageManager;
import android.media.MediaPlayer;
import android.os.Handler;
import android.os.IBinder;
import android.os.Message;
import android.support.annotation.NonNull;
import android.support.v4.app.ActivityCompat;
import android.support.v4.content.ContextCompat;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.SeekBar;
import android.widget.Toast;

import java.io.File;
import java.io.IOException;

public class MainActivity extends AppCompatActivity {
    private myMusicService iMusicService;
    private MyConn conn;
    private static SeekBar seekBar;
    public static Handler handler=new Handler(){
        public void handleMessage(Message msg) {
            //获取数据
            Bundle bundle=msg.getData();
            int duration=bundle.getInt("duration");
            int currentPosition = bundle.getInt("currentPosition");
            seekBar.setMax(duration);
            seekBar.setProgress(currentPosition);
        }
    };
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        if (ContextCompat.checkSelfPermission(MainActivity.this, Manifest.permission.WRITE_EXTERNAL_STORAGE) !=
                PackageManager.PERMISSION_GRANTED){
            ActivityCompat.requestPermissions(MainActivity.this,new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE},1);
        }
        Intent intent=new Intent(this,MusicService.class);
        startService(intent);
        conn=new MyConn();
        bindService(intent,conn,BIND_AUTO_CREATE);
        //找到seekBar
        seekBar=(SeekBar)findViewById(R.id.sb);
    }
    public void play(View v){
        iMusicService.startPlay();
    }
    public void replay(View v){
        iMusicService.repaly();
    }
    public void pause(View v){
        iMusicService.pausePlay();
    }
    public void stop(View v){
        iMusicService.stopPlay();
    }
    private class MyConn implements ServiceConnection {
        @Override
        public void onServiceConnected(ComponentName componentName, IBinder iBinder) {
            iMusicService=(myMusicService)iBinder;
        }

        @Override
        public void onServiceDisconnected(ComponentName componentName) {

        }
    }
    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        switch (requestCode){
            case 1:
                if (grantResults.length<0&&grantResults[0]!=PackageManager.PERMISSION_GRANTED){
                    Toast.makeText(this,"不授权将无法使用",Toast.LENGTH_LONG).show();
                }
        }
    }
}

 4.添加通过拖动进度条调整播放进度

4.1在服务当中监视当前歌曲播放进度,并通过handler.sendMessage方法进行把数据传递当MainActivity中

private void updateSeekBar() {
        //获取当前播放总进度
        final int duration=mediaPlayer.getDuration();
        //使用timer
        final Timer timer=new Timer();
        final TimerTask task=new TimerTask() {
            @Override
            public void run() {
                int currentPosition=mediaPlayer.getCurrentPosition();
                Message msg=Message.obtain();
                Bundle bundle=new Bundle();
                bundle.putInt("duration",duration);
                bundle.putInt("currentPosition",currentPosition);
                msg.setData(bundle);
                MainActivity.handler.sendMessage(msg);
            }
        };
        timer.schedule(task,100,1000);
        //当歌曲执行完毕后取消
        mediaPlayer.setOnCompletionListener(new MediaPlayer.OnCompletionListener() {
            @Override
            public void onCompletion(MediaPlayer mediaPlayer) {
                timer.cancel();
                task.cancel();
            }
        });
    }

4.2在handler类中调用handlermessage方法，对于服务所传递过来的数据进行操作

public static Handler handler=new Handler(){
        public void handleMessage(Message msg) {
            //获取数据
            Bundle bundle=msg.getData();
            int duration=bundle.getInt("duration");
            int currentPosition = bundle.getInt("currentPosition");
            seekBar.setMax(duration);
            seekBar.setProgress(currentPosition);
        }
    };

4.3通过设置对进度条的监听事件调用MediaPlayer类中的seekTo方法

   seekBar.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener() {
            @Override
            public void onProgressChanged(SeekBar seekBar, int i, boolean b) {
                //当进度改变调用
            }

            @Override
            public void onStartTrackingTouch(SeekBar seekBar) {

            }
            @Override
            public void onStopTrackingTouch(SeekBar seekBar) {
                //拖动停止调用
                iMusicService.seekToPlay(seekBar.getProgress());
            }
        });