音乐播放器中综合了以下内容：
SeekBar、ListView、广播接收者(以代码的形式注册Receiver)、系统服务、MediaPlayer
实现的功能：
1.暂停/播放、下一首/上一首，点击某一首时播放
2.支持拖动进度条快进
3.列表排序
4.来电话时，停止播放，挂断后继续播放
5.可在后台播放
效果图：
界面：
main.xml：
<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="/apk/res/android"android:orientation="vertical"android:layout_width="fill_parent"android:layout_height="fill_parent"><TextView android:id="@+id/name"android:layout_width="fill_parent" android:layout_height="wrap_content" /><SeekBarandroid:id="@+id/seekBar"android:layout_width="fill_parent" android:layout_height="wrap_content" android:layout_marginBottom="5dp"/><LinearLayoutandroid:layout_width="fill_parent" android:layout_height="wrap_content" android:layout_marginBottom="20dp"><Buttonandroid:layout_width="40dp" android:layout_height="40dp" android:text="|◀"android:onClick="previous"/><Buttonandroid:id="@+id/pp"android:layout_width="40dp" android:layout_height="40dp" android:text="▶"android:onClick="pp"/><Buttonandroid:layout_width="40dp" android:layout_height="40dp" android:text="▶|"android:onClick="next"/></LinearLayout><ListViewandroid:id="@+id/list"android:layout_width="fill_parent" android:layout_height="fill_parent" /></LinearLayout>
item.xml：
<?xml version="1.0" encoding="utf-8"?><LinearLayoutxmlns:android="/apk/res/android"android:layout_width="fill_parent"android:layout_height="wrap_content"android:padding="10dp"><TextViewandroid:id="@+id/mName"android:layout_width="fill_parent"android:layout_height="wrap_content"android:textSize="15sp"/></LinearLayout>
MainActivity:
package cn.test.audio;import java.io.File;import java.util.ArrayList;import java.util.Collections;import java.util.HashMap;import java.util.List;import java.util.Map;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.media.MediaPlayer.OnCompletionListener;import android.os.Bundle;import android.os.Environment;import android.os.Handler;import android.telephony.PhoneStateListener;import android.telephony.TelephonyManager;import android.view.View;import android.widget.AdapterView;import android.widget.Button;import android.widget.ListView;import android.widget.SeekBar;import android.widget.SimpleAdapter;import android.widget.TextView;import android.widget.AdapterView.OnItemClickListener;import android.widget.SeekBar.OnSeekBarChangeListener;public class MainActivity extends Activity {private TextView nameTextView;private SeekBar seekBar;private ListView listView;private List<Map<String, String>> data;private int current;private MediaPlayer player;private Handler handler = new Handler();private Button ppButton;private boolean isPause;private boolean isStartTrackingTouch;public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState);setContentView(R.layout.main);nameTextView = (TextView) findViewById(R.id.name);seekBar = (SeekBar) findViewById(R.id.seekBar);listView = (ListView) findViewById(R.id.list);ppButton = (Button) findViewById(R.id.pp);//创建一个音乐播放器player = new MediaPlayer();//显示音乐播放列表generateListView();//进度条监听器seekBar.setOnSeekBarChangeListener(new MySeekBarListener());//播放器监听器player.setOnCompletionListener(new MyPlayerListener());//意图过滤器IntentFilter filter = new IntentFilter();//播出电话暂停音乐播放filter.addAction("android.intent.action.NEW_OUTGOING_CALL");registerReceiver(new PhoneListener(), filter);//创建一个电话服务TelephonyManager manager = (TelephonyManager) getSystemService(TELEPHONY_SERVICE);//监听电话状态，接电话时停止播放manager.listen(new MyPhoneStateListener(), PhoneStateListener.LISTEN_CALL_STATE);}/** 监听电话状态*/private final class MyPhoneStateListener extends PhoneStateListener {public void onCallStateChanged(int state, String incomingNumber) {pause();}}/** 播放器监听器*/private final class MyPlayerListener implements OnCompletionListener {//歌曲播放完后自动播放下一首歌曲public void onCompletion(MediaPlayer mp) {next();}}/** 下一首按钮*/public void next(View view) {next();}/** 前一首按钮*/public void previous(View view) {previous();}/** 播放前一首歌*/private void previous() {current = current - 1 < 0 ? data.size() - 1 : current - 1;play();}/** 播放下一首歌*/private void next() {current = (current + 1) % data.size();play();}/** 进度条监听器*/private final class MySeekBarListener implements OnSeekBarChangeListener {//移动触发public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) {}//起始触发public void onStartTrackingTouch(SeekBar seekBar) {isStartTrackingTouch = true;}//结束触发public void onStopTrackingTouch(SeekBar seekBar) {player.seekTo(seekBar.getProgress());isStartTrackingTouch = false;}}/** 显示音乐播放列表*/private void generateListView() {List<File> list = new ArrayList<File>();//获取sdcard中的所有歌曲findAll(Environment.getExternalStorageDirectory(), list);//播放列表进行排序，字符顺序Collections.sort(list);data = new ArrayList<Map<String, String>>();for (File file : list) {Map<String, String> map = new HashMap<String, String>();map.put("name", file.getName());map.put("path", file.getAbsolutePath());data.add(map);}SimpleAdapter adapter = new SimpleAdapter(this, data, R.layout.item, new String[] { "name" }, new int[] { R.id.mName });listView.setAdapter(adapter);listView.setOnItemClickListener(new MyItemListener());}private final class MyItemListener implements OnItemClickListener {public void onItemClick(AdapterView<?> parent, View view, int position, long id) {current = position;play();}}private void play() {try {//重播player.reset();//获取歌曲路径player.setDataSource(data.get(current).get("path"));//缓冲player.prepare();//开始播放player.start();//显示歌名nameTextView.setText(data.get(current).get("name"));//设置进度条长度seekBar.setMax(player.getDuration());//播放按钮样式ppButton.setText("||");//发送一个Runnable, handler收到之后就会执行run()方法handler.post(new Runnable() {public void run() {// 更新进度条状态if (!isStartTrackingTouch)seekBar.setProgress(player.getCurrentPosition());// 1秒之后再次发送handler.postDelayed(this, 1000);}});} catch (Exception e) {e.printStackTrace();}}/*** 查找文件路径中所有mp3文件* @param file 要找的目录* @param list 用来装文件的List*/private void findAll(File file, List<File> list) {File[] subFiles = file.listFiles();if (subFiles != null)for (File subFile : subFiles) {if (subFile.isFile() && subFile.getName().endsWith(".mp3"))list.add(subFile);else if (subFile.isDirectory())//如果是目录findAll(subFile, list); //递归}}/** 暂停/播放按钮*/public void pp(View view) {//默认从第一首歌曲开始播放if (!player.isPlaying() && !isPause) {play();return;}Button button = (Button) view;//暂停/播放按钮if ("||".equals(button.getText())) {pause();button.setText("▶");} else {resume();button.setText("||");}}/** 开始操作*/private void resume() {if (isPause) {player.start();isPause = false;}}/** 暂停操作*/private void pause() {if (player != null && player.isPlaying()) {player.pause();isPause = true;}}/** 收到广播时暂停*/private final class PhoneListener extends BroadcastReceiver {public void onReceive(Context context, Intent intent) {pause();}}/** 恢复播放* @see android.app.Activity#onResume()*/protected void onResume() {super.onResume();resume();}}
注册权限：
<?xml version="1.0" encoding="utf-8"?><manifest xmlns:android="/apk/res/android"package="cn.itcast.audio"android:versionCode="1"android:versionName="1.0"><application android:icon="@drawable/icon" android:label="@string/app_name"><activity android:name=".MainActivity"android:label="@string/app_name"><intent-filter><action android:name="android.intent.action.MAIN" /><category android:name="android.intent.category.LAUNCHER" /></intent-filter></activity></application><uses-sdk android:minSdkVersion="8" /><!-- 监听电话呼出 --><uses-permission android:name="android.permission.PROCESS_OUTGOING_CALLS"/><!-- 监听电话状态改变 --><uses-permission android:name="android.permission.READ_PHONE_STATE" /> </manifest>
