此播放器的播放操作交给后台执行,二者通过广播进行进行通信(双向通信),前台点击播放暂停停止按钮通过广播发送给后台,后台播放变换通过广播通知前台。
前台代码
package org.crazyit.broadcast; 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.view.View.OnClickListener; import android.widget.ImageButton; import android.widget.TextView; /** * Description: * <br/>site: <a href="http://www.crazyit.org">crazyit.org</a> * <br/>Copyright (C), 2001-2014, Yeeku.H.Lee * <br/>This program is protected by copyright laws. * <br/>Program Name: * <br/>Date: * @author Yeeku.H.Lee kongyeeku@163.com * @version 1.0 */ public class MusicBox extends Activity implements OnClickListener { // 获取界面中显示歌曲标题、作者文本框 TextView title, author; // 播放/暂停、停止按钮 ImageButton play, stop; ActivityReceiver activityReceiver; public static final String CTL_ACTION = "org.crazyit.action.CTL_ACTION"; public static final String UPDATE_ACTION = "org.crazyit.action.UPDATE_ACTION"; // 定义音乐的播放状态,0x11代表没有播放;0x12代表正在播放;0x13代表暂停 int status = 0x11; String[] titleStrs = new String[] { "心愿", "约定", "美丽新世界" }; String[] authorStrs = new String[] { "未知艺术家", "周蕙", "伍佰" }; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); // 获取程序界面界面中的两个按钮 play = (ImageButton) this.findViewById(R.id.play); stop = (ImageButton) this.findViewById(R.id.stop); title = (TextView) findViewById(R.id.title); author = (TextView) findViewById(R.id.author); // 为两个按钮的单击事件添加监听器 play.setOnClickListener(this); stop.setOnClickListener(this); activityReceiver = new ActivityReceiver(); // 创建IntentFilter IntentFilter filter = new IntentFilter(); // 指定BroadcastReceiver监听的Action filter.addAction(UPDATE_ACTION); // 注册BroadcastReceiver registerReceiver(activityReceiver, filter); Intent intent = new Intent(this, MusicService.class); // 启动后台Service startService(intent); } // 自定义的BroadcastReceiver,负责监听从Service传回来的广播 public class ActivityReceiver extends BroadcastReceiver { @Override public void onReceive(Context context, Intent intent) { // 获取Intent中的update消息,update代表播放状态 int update = intent.getIntExtra("update", -1); // 获取Intent中的current消息,current代表当前正在播放的歌曲 int current = intent.getIntExtra("current", -1); if (current >= 0) { title.setText(titleStrs[current]); author.setText(authorStrs[current]); } switch (update) { case 0x11: play.setImageResource(R.drawable.play); status = 0x11; break; // 控制系统进入播放状态 case 0x12: // 播放状态下设置使用暂停图标 play.setImageResource(R.drawable.pause); // 设置当前状态 status = 0x12; break; // 控制系统进入暂停状态 case 0x13: // 暂停状态下设置使用播放图标 play.setImageResource(R.drawable.play); // 设置当前状态 status = 0x13; break; } } } @Override public void onClick(View source) { // 创建Intent Intent intent = new Intent("org.crazyit.action.CTL_ACTION"); switch (source.getId()) { // 按下播放/暂停按钮 case R.id.play: intent.putExtra("control", 1); break; // 按下停止按钮 case R.id.stop: intent.putExtra("control", 2); break; } // 发送广播,将被Service组件中的BroadcastReceiver接收到 sendBroadcast(intent); } }
后台服务
/** * */ package org.crazyit.broadcast; import java.io.IOException; 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.media.MediaPlayer.OnCompletionListener; import android.os.IBinder; /** * Description: * <br/>网站: <a href="http://www.crazyit.org">疯狂Java联盟</a> * <br/>Copyright (C), 2001-2014, Yeeku.H.Lee * <br/>This program is protected by copyright laws. * <br/>Program Name: * <br/>Date: * @author Yeeku.H.Lee kongyeeku@163.com * @version 1.0 */ public class MusicService extends Service { MyReceiver serviceReceiver; AssetManager am; String[] musics = new String[] { "wish.mp3", "promise.mp3", "beautiful.mp3" }; MediaPlayer mPlayer; // 当前的状态,0x11 代表没有播放 ;0x12代表 正在播放;0x13代表暂停 int status = 0x11; // 记录当前正在播放的音乐 int current = 0; @Override public IBinder onBind(Intent intent) { return null; } @Override public void onCreate() { am = getAssets(); // 创建BroadcastReceiver serviceReceiver = new MyReceiver(); // 创建IntentFilter IntentFilter filter = new IntentFilter(); filter.addAction(MusicBox.CTL_ACTION); registerReceiver(serviceReceiver, filter); // 创建MediaPlayer mPlayer = new MediaPlayer(); // 为MediaPlayer播放完成事件绑定监听器 mPlayer.setOnCompletionListener(new OnCompletionListener() //① { @Override public void onCompletion(MediaPlayer mp) { current++; if (current >= 3) { current = 0; } // 发送广播通知Activity更改文本框 Intent sendIntent = new Intent(MusicBox.UPDATE_ACTION); sendIntent.putExtra("current", current); // 发送广播 ,将被Activity组件中的BroadcastReceiver接收到 sendBroadcast(sendIntent); // 准备、并播放音乐 prepareAndPlay(musics[current]); } }); super.onCreate(); } public class MyReceiver extends BroadcastReceiver { @Override public void onReceive(final Context context, Intent intent) { int control = intent.getIntExtra("control", -1); switch (control) { // 播放或暂停 case 1: // 原来处于没有播放状态 if (status == 0x11) { // 准备、并播放音乐 prepareAndPlay(musics[current]); status = 0x12; } // 原来处于播放状态 else if (status == 0x12) { // 暂停 mPlayer.pause(); // 改变为暂停状态 status = 0x13; } // 原来处于暂停状态 else if (status == 0x13) { // 播放 mPlayer.start(); // 改变状态 status = 0x12; } break; // 停止声音 case 2: // 如果原来正在播放或暂停 if (status == 0x12 || status == 0x13) { // 停止播放 mPlayer.stop(); status = 0x11; } } // 发送广播通知Activity更改图标、文本框 Intent sendIntent = new Intent(MusicBox.UPDATE_ACTION); sendIntent.putExtra("update", status); sendIntent.putExtra("current", current); // 发送广播 ,将被Activity组件中的BroadcastReceiver接收到 sendBroadcast(sendIntent); } } private void prepareAndPlay(String music) { try { // 打开指定音乐文件 AssetFileDescriptor afd = am.openFd(music); mPlayer.reset(); // 使用MediaPlayer加载指定的声音文件。 mPlayer.setDataSource(afd.getFileDescriptor(), afd.getStartOffset(), afd.getLength()); // 准备声音 mPlayer.prepare(); // 播放 mPlayer.start(); } catch (IOException e) { e.printStackTrace(); } } }
布局文件
<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:orientation="horizontal" android:layout_width="fill_parent" android:layout_height="wrap_content"> <ImageButton android:id="@+id/play" android:layout_width="wrap_content" android:layout_height="wrap_content" android:src="@drawable/play"/> <ImageButton android:id="@+id/stop" android:layout_width="wrap_content" android:layout_height="wrap_content" android:src="@drawable/stop"/> <LinearLayout android:orientation="vertical" android:layout_width="fill_parent" android:layout_height="fill_parent"> <TextView android:id="@+id/title" android:layout_width="wrap_content" android:layout_height="wrap_content" android:textSize="25px" android:textColor="#ffffff" android:ellipsize="marquee" android:layout_weight="1" android:marqueeRepeatLimit="marquee_forever"/> <TextView android:id="@+id/author" android:textSize="15px" android:gravity="center_vertical" android:layout_weight="1" android:layout_width="wrap_content" android:layout_height="wrap_content"/> </LinearLayout> </LinearLayout>
配置文件
<?xml version="1.0" encoding="utf-8"?> <manifest xmlns:android="http://schemas.android.com/apk/res/android" package="org.crazyit.broadcast" android:versionCode="1" android:versionName="1.0"> <uses-sdk android:minSdkVersion="10" android:targetSdkVersion="17" /> <application android:icon="@drawable/ic_launcher" android:label="@string/app_name"> <activity android:name=".MusicBox" android:label="@string/app_name"> <intent-filter> <action android:name="android.intent.action.MAIN" /> <category android:name="android.intent.category.LAUNCHER" /> </intent-filter> </activity> <service android:name=".MusicService"> </service> </application> </manifest>