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。