音乐播放器之--音乐播放

在线播放音乐并不难，也就是传入的Url是一个网络地址。这里我要实现一个可以进行网络缓冲的在线音乐播放。

下面介绍具体实现过程：

定义一个具有缓冲效果的播放器：Player 我们看到的缓冲效果，是通过设置拖动条SeekBar的二级进度实现的，这就要设置MediaPlayer的缓冲更新的监听了。 具体代码实现：

package com.wwj.download.util;import java.io.IOException;import java.util.Timer;import java.util.TimerTask;import android.media.AudioManager;import android.media.MediaPlayer;import android.media.MediaPlayer.OnBufferingUpdateListener;import android.media.MediaPlayer.OnCompletionListener;import android.media.MediaPlayer.OnPreparedListener;import android.os.Handler;import android.util.Log;import android.widget.SeekBar;public class Player implements OnBufferingUpdateListener, OnCompletionListener,OnPreparedListener {public MediaPlayer mediaPlayer; // 媒体播放器private SeekBar seekBar; // 拖动条private Timer mTimer = new Timer(); // 计时器// 初始化播放器public Player(SeekBar seekBar) {super();this.seekBar = seekBar;try {mediaPlayer = new MediaPlayer();mediaPlayer.setAudioStreamType(AudioManager.STREAM_MUSIC);// 设置媒体流类型mediaPlayer.setOnBufferingUpdateListener(this);mediaPlayer.setOnPreparedListener(this);} catch (Exception e) {e.printStackTrace();}// 每一秒触发一次mTimer.schedule(timerTask, 0, 1000);}// 计时器TimerTask timerTask = new TimerTask() {@Overridepublic void run() {if (mediaPlayer == null)return;if (mediaPlayer.isPlaying() && seekBar.isPressed() == false) {handler.sendEmptyMessage(0); // 发送消息}}};Handler handler = new Handler() {public void handleMessage(android.os.Message msg) {int position = mediaPlayer.getCurrentPosition();int duration = mediaPlayer.getDuration();if (duration > 0) {// 计算进度（获取进度条最大刻度*当前音乐播放位置 / 当前音乐时长）long pos = seekBar.getMax() * position / duration;seekBar.setProgress((int) pos);}};};public void play() {mediaPlayer.start();}/*** * @param url* url地址*/public void playUrl(String url) {try {mediaPlayer.reset();mediaPlayer.setDataSource(url); // 设置数据源mediaPlayer.prepare(); // prepare自动播放} catch (IllegalArgumentException e) {e.printStackTrace();} catch (SecurityException e) {e.printStackTrace();} catch (IllegalStateException e) {e.printStackTrace();} catch (IOException e) {e.printStackTrace();}}// 暂停public void pause() {mediaPlayer.pause();}// 停止public void stop() {if (mediaPlayer != null) {mediaPlayer.stop();mediaPlayer.release();mediaPlayer = null;}}// 播放准备@Overridepublic void onPrepared(MediaPlayer mp) {mp.start();Log.e("mediaPlayer", "onPrepared");}// 播放完成@Overridepublic void onCompletion(MediaPlayer mp) {Log.e("mediaPlayer", "onCompletion");}/*** 缓冲更新*/@Overridepublic void onBufferingUpdate(MediaPlayer mp, int percent) {seekBar.setSecondaryProgress(percent);int currentProgress = seekBar.getMax()* mediaPlayer.getCurrentPosition() / mediaPlayer.getDuration();Log.e(currentProgress + "% play", percent + " buffer");}}

package com.wwj.download;import java.io.File;import java.io.UnsupportedEncodingException;import .URLEncoder;import android.app.Activity;import android.os.Bundle;import android.os.Environment;import android.os.Handler;import android.os.Message;import android.view.View;import android.widget.Button;import android.widget.EditText;import android.widget.ProgressBar;import android.widget.SeekBar;import android.widget.SeekBar.OnSeekBarChangeListener;import android.widget.TextView;import android.widget.Toast;import com.wwj.download.util.Player;import .download.DownloadProgressListener;import .download.FileDownloader;public class MainActivity extends Activity {private static final int PROCESSING = 1;private static final int FAILURE = -1;private EditText pathText; // url地址private TextView resultView;private Button downloadButton;private Button stopButton;private ProgressBar progressBar;private Button playBtn;private Player player; // 播放器private SeekBar musicProgress; // 音乐进度private Handler handler = new UIHandler();private final class UIHandler extends Handler {public void handleMessage(Message msg) {switch (msg.what) {case PROCESSING: // 更新进度progressBar.setProgress(msg.getData().getInt("size"));float num = (float) progressBar.getProgress()/ (float) progressBar.getMax();int result = (int) (num * 100); // 计算进度resultView.setText(result + "%");if (progressBar.getProgress() == progressBar.getMax()) { // 下载完成Toast.makeText(getApplicationContext(), R.string.success,Toast.LENGTH_LONG).show();}break;case FAILURE: // 下载失败Toast.makeText(getApplicationContext(), R.string.error,Toast.LENGTH_LONG).show();break;}}}@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.main);pathText = (EditText) findViewById(R.id.path);resultView = (TextView) findViewById(R.id.resultView);downloadButton = (Button) findViewById(R.id.downloadbutton);stopButton = (Button) findViewById(R.id.stopbutton);progressBar = (ProgressBar) findViewById(R.id.progressBar);ButtonClickListener listener = new ButtonClickListener();downloadButton.setOnClickListener(listener);stopButton.setOnClickListener(listener);playBtn = (Button) findViewById(R.id.btn_online_play);playBtn.setOnClickListener(listener);musicProgress = (SeekBar) findViewById(R.id.music_progress);player = new Player(musicProgress);musicProgress.setOnSeekBarChangeListener(new SeekBarChangeEvent());}private final class ButtonClickListener implements View.OnClickListener {@Overridepublic void onClick(View v) {switch (v.getId()) {case R.id.downloadbutton: // 开始下载// /music/光辉岁月.mp3，可以换成其他文件下载的链接String path = pathText.getText().toString();String filename = path.substring(path.lastIndexOf('/') + 1);try {// URL编码（这里是为了将中文进行URL编码）filename = URLEncoder.encode(filename, "UTF-8");} catch (UnsupportedEncodingException e) {e.printStackTrace();}path = path.substring(0, path.lastIndexOf("/") + 1) + filename;if (Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)) {// File savDir =// Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_MOVIES);// 保存路径File savDir = Environment.getExternalStorageDirectory();download(path, savDir);} else {Toast.makeText(getApplicationContext(),R.string.sdcarderror, Toast.LENGTH_LONG).show();}downloadButton.setEnabled(false);stopButton.setEnabled(true);break;case R.id.stopbutton: // 暂停下载exit();Toast.makeText(getApplicationContext(),"Now thread is Stopping!!", Toast.LENGTH_LONG).show();downloadButton.setEnabled(true);stopButton.setEnabled(false);break;case R.id.btn_online_play:new Thread(new Runnable() {@Overridepublic void run() {player.playUrl(pathText.getText().toString());}}).start();break;}}/** 由于用户的输入事件(点击button, 触摸屏幕....)是由主线程负责处理的，如果主线程处于工作状态，* 此时用户产生的输入事件如果没能在5秒内得到处理，系统就会报“应用无响应”错误。* 所以在主线程里不能执行一件比较耗时的工作，否则会因主线程阻塞而无法处理用户的输入事件，* 导致“应用无响应”错误的出现。耗时的工作应该在子线程里执行。*/private DownloadTask task;private void exit() {if (task != null)task.exit();}private void download(String path, File savDir) {task = new DownloadTask(path, savDir);new Thread(task).start();}/*** * UI控件画面的重绘(更新)是由主线程负责处理的，如果在子线程中更新UI控件的值，更新后的值不会重绘到屏幕上* 一定要在主线程里更新UI控件的值，这样才能在屏幕上显示出来，不能在子线程中更新UI控件的值* */private final class DownloadTask implements Runnable {private String path;private File saveDir;private FileDownloader loader;public DownloadTask(String path, File saveDir) {this.path = path;this.saveDir = saveDir;}/*** 退出下载*/public void exit() {if (loader != null)loader.exit();}DownloadProgressListener downloadProgressListener = new DownloadProgressListener() {@Overridepublic void onDownloadSize(int size) {Message msg = new Message();msg.what = PROCESSING;msg.getData().putInt("size", size);handler.sendMessage(msg);}};public void run() {try {// 实例化一个文件下载器loader = new FileDownloader(getApplicationContext(), path,saveDir, 3);// 设置进度条最大值progressBar.setMax(loader.getFileSize());loader.download(downloadProgressListener);} catch (Exception e) {e.printStackTrace();handler.sendMessage(handler.obtainMessage(FAILURE)); // 发送一条空消息对象}}}}// 进度改变class SeekBarChangeEvent implements OnSeekBarChangeListener {int progress;@Overridepublic void onProgressChanged(SeekBar seekBar, int progress,boolean fromUser) {// 原本是(progress/seekBar.getMax())*player.mediaPlayer.getDuration()this.progress = progress * player.mediaPlayer.getDuration()/ seekBar.getMax();}@Overridepublic void onStartTrackingTouch(SeekBar seekBar) {}@Overridepublic void onStopTrackingTouch(SeekBar seekBar) {// seekTo()的参数是相对与影片时间的数字，而不是与seekBar.getMax()相对的数字player.mediaPlayer.seekTo(progress);}}@Overrideprotected void onDestroy() {super.onDestroy();if (player != null) {player.stop();player = null;}}}

源自： /wwj_748/article/details/20933055

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