音乐播放器之简单播放（MediaPlayer、Service、BroadcastRecevier的结合用法）

(小白一个，代码仅供参考)

做一个音乐播放器，就要考虑到实现后台音乐的播放，进度条的实现，播放时间和音频时间的实现。 在Android中，BroadcastRecevier Service 和 MediaPlayer就可以实现下面的操作。

先看Activity

package com.example.bear.test;

import android.app.Activity;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.ImageButton;
import android.widget.SeekBar;
import android.widget.TextView;

public class MainActivity extends Activity implements View.OnClickListener{ //为日志工具设置标签 private static String TAG = "MusicService"; protected boolean isplay = false; private static final int PLAY = 1; private static final int PAUSE = 2; private static final int STOP = 3;// 停止 private static final int PROGRESS_CHANGE = 4; private static final int STATE_PLAY = 1;// 播放状态设为1 private static final int STATE_PAUSE = 2;// 播放状态设为2 private SeekBar mSeekBar; private ImageButton btnStart; private Button btnStop; private int flag;// 标记 private TextView startTime, stopTime; private MyBroadcastReceiver myBroadcastReceiver = new MyBroadcastReceiver(); /** * Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); initlizeViews(); } @Override protected void onResume() { super.onResume(); //注册广播接收器 IntentFilter filter = new IntentFilter(); //设置接收广播的类型，这里要和Service里设置的类型匹配，还可以在AndroidManifest.xml文件中注册 filter.addAction("com.bear.app"); this.registerReceiver(myBroadcastReceiver, filter); mSeekBar.setProgress(0); play(); } @Override protected void onStop() { super.onStop(); this.unregisterReceiver(myBroadcastReceiver); } @Override protected void onDestroy() { super.onDestroy(); stop(); this.unregisterReceiver(myBroadcastReceiver); finish(); } private void initlizeViews() { btnStart = (ImageButton) findViewById(R.id.startMusic); btnStop = (Button) findViewById(R.id.stopMusic); mSeekBar = (SeekBar) findViewById(R.id.seekbar1); startTime = (TextView) findViewById(R.id.startTime); stopTime = (TextView) findViewById(R.id.stopTime); //绑定点击监听 btnStart.setOnClickListener(this); btnStop.setOnClickListener(this); ShowSeekBar(); } @Override public void onClick(View v) { //显示指定 intent所指的对象是个 service if(v.getId() == R.id.startMusic){ switch (flag) { case STATE_PLAY:
                    //开始服务
                    pause();
                    break;
                case STATE_PAUSE:
                    //停止服务
                    play();
                    break;
            }
        }else {
            stop();
        }

    }

    private void stop() {
        Intent intent = new Intent();
        intent.setAction("com.app.media.MUSIC_SERVICE");
        intent.setPackage(getPackageName());
        stopService(intent);
    }

    private void ShowSeekBar() {
        mSeekBar.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener() {
            @Override
            public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) {
                if (fromUser) {
                    Intent intent = new Intent();
                    intent.setAction("com.app.media.MUSIC_SERVICE");
                    intent.setPackage(getPackageName());
                    intent.putExtra("op", PROGRESS_CHANGE);
                    intent.putExtra("progress", progress);
                    startService(intent);
                }
            }

            @Override
            public void onStartTrackingTouch(SeekBar seekBar) {

            }

            @Override
            public void onStopTrackingTouch(SeekBar seekBar) {

            }
        });
    }

    /**
     * 播放时间转换
     */
    public String toTime(int time) {

        time /= 1000;
        int minute = time / 60;
        int second = time % 60;
        minute %= 60;
        return String.format("%02d:%02d", minute, second);
    }

    /**
     * 在播放布局里先把播放按钮先删除并用background设置为透明。然后在代码添加按钮
     */
    public void play() {
        flag = PLAY;
        btnStart.setImageResource(R.drawable.player_btn_player_pause);
        Intent intent = new Intent();
        intent.setAction("com.app.media.MUSIC_SERVICE");
        intent.setPackage(getPackageName());
        intent.putExtra("op", PLAY);// 向服务传递数据
        startService(intent);

    }
    /**
     * 暂停
     */
    public void pause() {
        flag = PAUSE;
        btnStart.setImageResource(R.drawable.player_btn_player_play);
        Intent intent = new Intent();
        intent.setAction("com.app.media.MUSIC_SERVICE");
        intent.setPackage(getPackageName());
        intent.putExtra("op", PAUSE);
        startService(intent);

    }

    class MyBroadcastReceiver extends BroadcastReceiver { @Override public void onReceive(Context context, Intent intent) { int duration = intent.getIntExtra("duration",-1); int progress = intent.getIntExtra("seekBarProgress",-1); if(duration != -1){ mSeekBar.setMax(duration); stopTime.setText(toTime(duration)); } if(progress != -1){ mSeekBar.setProgress(progress); startTime.setText(toTime(progress)); } } } } 

在MainActivity中，我把play、pause、和改变进度条的事件传到service中，然后在service中实现；而且在service中把音频的总长度和当前播放长度传到主线程中，从而实现了以上功能

看Service

package com.example.bear.test;

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

/**
 * Created by Bear on 2015/8/7.
 */
public class MusicService extends Service{ //为日志工具设置标签 private static String TAG = "MusicService"; //定义音乐播放器变量 private MediaPlayer mPlayer; private final int mSeekBarLen = 2000; private SeekBarThread seekBarThread; private static final int MUSIC_PLAY = 1; private static final int MUSIC_PAUSE = 2; private static final int MUSIC_STOP = 3; private static final int PROGRESS_CHANGE = 4; //该服务不存在需要被创建时被调用，不管startService()还是bindService()都会启动时调用该方法 @Override public void onCreate() { mPlayer = MediaPlayer.create(getApplicationContext(), R.raw.music); //设置可以重复播放 mPlayer.setLooping(true); super.onCreate(); } @Override public int onStartCommand(Intent intent, int flags, int startId) { startBarThread(); int op = intent.getIntExtra("op",-1); if(op != -1) { switch (op) { case MUSIC_PLAY:
                    if (!mPlayer.isPlaying()) {
                        mPlayer.start();
                    }
                    break;
                case MUSIC_PAUSE:
                    if (mPlayer.isPlaying()) {
                        mPlayer.pause();
                    }
                    break;
                case PROGRESS_CHANGE:
                    int currentTime = intent.getExtras().getInt("progress");
                    mPlayer.seekTo(currentTime);
                    break;
            }
        }
        return super.onStartCommand(intent, flags, startId);
    }


    @Override
    public void onDestroy() {
        mPlayer.stop();
        if (seekBarThread != null) {
            seekBarThread.off();
        }
        super.onDestroy();
    }

    @Override
    public IBinder onBind(Intent intent) {
        return null;
    }

    private void startBarThread() {
        if (seekBarThread != null) {
            seekBarThread.off();
        }
        seekBarThread = new SeekBarThread();
        seekBarThread.start();
    }

    class SeekBarThread extends Thread { boolean flag = true; int duration = 1; int seekBarProgress = 0; int position = 0; public SeekBarThread() {}; public void off() { flag = false; } public void run() { flag = true; if(mPlayer!=null) { duration = mPlayer.getDuration(); } seekBarProgress = 0; position = 0; while (flag) { if(mPlayer!=null) { position = mPlayer.getCurrentPosition(); } seekBarProgress =position; // Log.e("TEST",position+""); // Log.e("TEST",seekBarProgress+""); // Log.e("TEST",duration+""); Intent intent = new Intent(); intent.putExtra("seekBarProgress",seekBarProgress); intent.putExtra("duration",duration); //设置广播的类型 intent.setAction("com.bear.app"); sendBroadcast(intent); try { sleep(1000); } catch (InterruptedException e) { e.printStackTrace(); } } }// while } } 

在service中，实现一个新的线程来实现音频时间的处理，从而减少主线程的时间。我们都知道，主线程时间不能够长，长时间的操作应该放到其他线程中。

注意：感觉说了这么多，还是没什么用，看代码才是重点。