這是一個音樂播放器到了server handler 廣播等；

package com.jorkyin.mymusic;

import android.app.Activity;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.media.MediaPlayer;
import android.os.Bundle;
import android.view.KeyEvent;
import
 
 android.view.View;
import android.widget.ImageView;
import android.widget.SeekBar;
import android.widget.TextView;
import android.widget.Toast;

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

/**
 * Created by YinJian on 2016/3/24.
 */
public class MusicPlayActivty extends Activity implements View
 
.OnClickListener {
    private boolean mPlayTab = true;
    private ImageView mMusicNextImageView, mMusicPlayImageView, mMusicPrevImageView;
    private TextView mMusicNameTextView, mMusicTotalHoursTextView, mMusicTimeingTextView;
    private SeekBar mMusictimeingSeekBar;
    public static final String CTL_ACTION = "com.jorkyin.mymusic.CTL_ACTION"
 
;
    public static final String UPFATE_ACTION = "com.jorkyin.mymusic.UPFATE_ACTION";
    private int status = 0x11;
    ActivityReceiver activityReceiver;
    String[] titleStrs = new String[]{"可惜沒有如果", "誣賴", "隱形的翅膀"};
    private Intent mIntent;
    private static boolean isExit = false;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_music_play);
        initActivity();
        //建立ActivityReceiver
        activityReceiver = new ActivityReceiver();
        //指定IntentFilter監聽的Activity
        IntentFilter filter = new IntentFilter();
        filter.addAction(UPFATE_ACTION);
        //註冊BroadcastReceiver
        registerReceiver(activityReceiver, filter);
        mIntent = new Intent(MusicPlayActivty.this, MusicService.class);
        //啟動後臺Service
        startService(mIntent);
    }

    private void initActivity() {
        mMusicNameTextView = (TextView) findViewById(R.id.music_name_id_tv);
        mMusicTimeingTextView = (TextView) findViewById(R.id.music_timeing_tv);
        mMusicTotalHoursTextView = (TextView) findViewById(R.id.music_total_hours_tv);

        mMusictimeingSeekBar = (SeekBar) findViewById(R.id.music_timeing_sb);

        mMusicPrevImageView = (ImageView) findViewById(R.id.music_prev_id_iv);
        mMusicPlayImageView = (ImageView) findViewById(R.id.music_play_id_iv);
        mMusicNextImageView = (ImageView) findViewById(R.id.music_next_id_iv);

        mMusicPrevImageView.setOnClickListener(this);
        mMusicPlayImageView.setOnClickListener(this);
        mMusicNextImageView.setOnClickListener(this);
    }

    @Override
    public void onClick(View v) {
        Intent intent = new Intent(CTL_ACTION);
        switch (v.getId()) {
            case R.id.music_prev_id_iv:
                intent.putExtra("control", 3);
                break;
            case R.id.music_play_id_iv:
                if (mPlayTab) {
                    intent.putExtra("control", 1);
                } else {
                    intent.putExtra("control", 2);
                }
                break;
            case R.id.music_next_id_iv:
                intent.putExtra("control", 4);
                break;
        }
        sendBroadcast(intent);
    }

    public class ActivityReceiver extends BroadcastReceiver {
        @Override
        public void onReceive(Context context, Intent intent) {
            int update = intent.getIntExtra("update", -1);
            int current = intent.getIntExtra("current", -1);
            int seekbar = intent.getIntExtra("seekbar", -1);
            int duration = intent.getIntExtra("duration", -1);
            if (current >= 0) {
                mMusicNameTextView.setText(titleStrs[current]);
            }
            switch (update) {
                case 0x11:
                    mMusicPlayImageView.setImageResource(R.mipmap.control_play);
                    status = 0x11;
                    break;

                case 0x12:
                    mMusicPlayImageView.setImageResource(R.mipmap.control_pause);
                    status = 0x12;
                    break;
                case 0x13:
                    mMusicPlayImageView.setImageResource(R.mipmap.control_play);
                    status = 0x13;
                    break;
            }
            if (duration >=0){
                mMusicTotalHoursTextView.setText(formatDuring(duration));
            }
            if (seekbar>=0){
                mMusictimeingSeekBar.setProgress(seekbar*mMusictimeingSeekBar.getMax()/duration);
                mMusicTimeingTextView.setText(formatDuring(seekbar));
            }

        }
    }

    private void exit() {
        if (!isExit) {
            isExit = true;
            Toast.makeText(this, "在按一次退出程式", Toast.LENGTH_SHORT).show();
            new Timer().schedule(new TimerTask() {
                @Override
                public void run() {
                    isExit = false;
                }
            }, 2000);
        } else {
            stopService(mIntent);
            finish();
        }
    }

    @Override
    public boolean onKeyDown(int keyCode, KeyEvent event) {
        if (keyCode == KeyEvent.KEYCODE_BACK) {
            exit();
        }
        return false;
    }
    private String formatDuring(long mss){
        String time="";
        long minutes = (mss % (1000 * 60 * 60)) / (1000 * 60);
        if (minutes<10){
            time=time+ "0"+minutes+":";
        }else{
            time=time+minutes+":";
        }

        long seconds = (mss % (1000 * 60)) / 1000;
        if (seconds<10){
            time=time+ "0"+seconds;
        }else{
            time=time+seconds;
        }
        return time;
    }
}

package com.jorkyin.mymusic;

import android.app.Service;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.content.res.AssetFileDescriptor;
import android.content.res.AssetManager;
import android.media.MediaPlayer;
import android.os.Handler;
import android.os.IBinder;
import android.provider.MediaStore;
import android.util.Log;
import android.widget.Toast;

import java.io.IOException;

/**
 * Created by YinJian on 2016/3/24.
 */
public class MusicService extends Service {
    private static final String TAG = MusicService.class.getSimpleName();
    private SetviceReceiver setviceReceiver;
    private MediaPlayer mMediaPlayer;// 媒體播放器物件
    private int current = 0;//記錄當前正在播放的音樂
    private int status = 0x11;//0x11：沒有播放  0x12：正在播放 0x13：暫停
    String[] musics = new String[]{"kxmyrg.mp3", "wl.mp3", "yxdcp.mp3"};
    Handler mHandler=new Handler();
    @Override
    public IBinder onBind(Intent intent) {
        return null;
    }

    @Override
    public void onCreate() {
        Log.i(TAG, "onCreate");
        super.onCreate();
        //建立BroadcastReceiver物件
        setviceReceiver = new SetviceReceiver();
        //建立IntentFilter物件
        IntentFilter filter = new IntentFilter();
        filter.addAction(MusicPlayActivty.CTL_ACTION);
        registerReceiver(setviceReceiver, filter);

        //在這裡我們需要例項化MediaPlayer物件
        mMediaPlayer = new MediaPlayer();
        mMediaPlayer.setOnCompletionListener(new MediaPlayer.OnCompletionListener() {
            @Override
            public void onCompletion(MediaPlayer mp) {
                current++;
                if (current >= 3) {
                    current = 0;
                }
                  prepareAndPlay(musics[current]);
            }
        });
        //傳送廣播通知Activity更改文字框
        Intent sendIntent = new Intent(MusicPlayActivty.UPFATE_ACTION);
        sendIntent.putExtra("current", current);
        //傳送廣播，蔣被Activity元件中的BroadcastReceiver接收到
        sendBroadcast(sendIntent);

    }

    public class SetviceReceiver extends BroadcastReceiver {
        @Override
        public void onReceive(Context context, Intent intent) {
            int control = intent.getIntExtra("control", -1);
            switch (control) {
                case 1:
                    if (status == 0x11) {
                        prepareAndPlay(musics[current]);
                        status = 0x12;
                    } else if (status == 0x12) {
                        mMediaPlayer.pause();
                        status = 0x13;
                    } else if (status == 0x13) {
                        mMediaPlayer.start();
                        status = 0x12;
                    }
                    break;
                case 2:
                    if (status == 0x12 || status == 0x13) {
                        mMediaPlayer.stop();
                        status = 0x11;
                    }
                    break;
                case 3:
                    current--;
                        if (current<0){
                            current=2;
                        }
                    prepareAndPlay(musics[current]);
                    status = 0x12;
                    break;
                case 4:
                    current++;
                    if (current>2){
                        current=0;
                    }
                    prepareAndPlay(musics[current]);
                    status = 0x12;
                    break;
            }
            //傳送廣播通知Activity更改文字框
            Intent sendIntent = new Intent(MusicPlayActivty.UPFATE_ACTION);
            sendIntent.putExtra("update", status);
            sendIntent.putExtra("current", current);
            //傳送廣播，蔣被Activity元件中的BroadcastReceiver接收到
            sendBroadcast(sendIntent);
        }
    }

    @Override
    public boolean stopService(Intent name) {
        mMediaPlayer.stop();
        return super.stopService(name);
    }

    private void prepareAndPlay(String music) {
        try {
            AssetFileDescriptor afd = getAssets().openFd(music);
            mMediaPlayer.reset();
            mMediaPlayer.setDataSource(afd.getFileDescriptor(), afd.getStartOffset(), afd.getLength());
            //準備聲音
            mMediaPlayer.prepare();
            //播放
            mMediaPlayer.start();
        } catch (IOException e) {
            e.printStackTrace();
        }

        //傳送廣播通知Activity更改文字框
        Intent sendIntent = new Intent(MusicPlayActivty.UPFATE_ACTION);

        sendIntent.putExtra("duration",mMediaPlayer.getDuration()/(60*1000));
        //傳送廣播，蔣被Activity元件中的BroadcastReceiver接收到
        sendBroadcast(sendIntent);

        mHandler.postDelayed(runnable, 2000);//每兩秒執行一次runnable.
    }

    Runnable runnable=new Runnable() {
        @Override
        public void run() {
            // TODO Auto-generated method stub
            //傳送廣播通知Activity更改文字框
            Intent sendIntent = new Intent(MusicPlayActivty.UPFATE_ACTION);
            sendIntent.putExtra("seekbar", mMediaPlayer.getCurrentPosition());

            sendIntent.putExtra("duration",mMediaPlayer.getDuration());
            //傳送廣播，蔣被Activity元件中的BroadcastReceiver接收到
            sendBroadcast(sendIntent);
            mHandler.postDelayed(this, 500);
        }
    };
}