今天比较开心，看到论坛上很多人都在询问如何写网络流媒体播放器？是否需要两个播放器轮流交替？因为Android没有提供像J2me那样的流创建的形式，总之还是不太好写，最近也在研究 android 流媒体播放，这里提供一个很早之前写的 demo, 以供大家相互学习和参考。
/**
* Android 提供的接口仍然是不能直接通过流创建 Player, 但是 Android 提供了很全面的文件系统接口，现在用一种新的方法来解决： <br>
* <1>, 把下载下来的数据先写到临时的文件中 <br>
* <2>, 用临时文件创建 Player<br>
* todo: <br>
* <1>, 清理没有用的临时文件。 <br>
* <2>, 暂停逻辑的优化。 --- 抛出异常。。。。 <br>
* <3>, 分段下载的逻辑处理，这和 <2> 有关系。 <br>
* <4>, 整体优化
*
* @author shenrenkui
*
*/
public class AudioPlayer implements OnErrorListener, OnBufferingUpdateListener,
MediaPlayer.OnCompletionListener {
private static final String TAG = "AudioPlayer";
private MediaPlayer mPlayer;
private String current;
private static final int MIN_BUFF = 100 * 1024;
private int totalKbRead = 0;
private Handler handler = new Handler();
private File DLTempFile;
private File BUFFTempFile;
private final String TEMP_DOWNLOAD_FILE_NAME = "tempMediaData";
private final String TEMP_BUFF_FILE_NAME = "tempBufferData";
private final String FILE_POSTFIX = ".dat";
private final int PER_READ = 1024;
private boolean pause;
private boolean stop;
private final int UNKNOWN_LENGTH = -1;
private Handler mHandler = null;
public void setHandler(Handler handler) {
mHandler = handler;
}
public void play(final String path) {
downloadOver = false;
totalKbRead = 0;
try {
Log.v(TAG, "playing: " + path);
if (path.equals(current) && mPlayer != null) {
mPlayer.start();
return;
}
current = path;
mPlayer = null;
new PlayThread(current).start();
} catch (Exception e) {
}
}
private void setListener() {
if (mPlayer != null) {
mPlayer.setOnErrorListener(this);
mPlayer.setOnBufferingUpdateListener(this);
mPlayer.setOnCompletionListener(this);
}
}
/**
* 下载数据，分段下载
* todo: 联网方式和分段
* @param mediaUrl
* @param start
* @param end
*/
private void playFromNet(String mediaUrl, int start, int end) {
URLConnection cn = null;
FileOutputStream out = null;
InputStream is = null;
try {
cn = new URL(mediaUrl).openConnection();
cn.connect();
is = cn.getInputStream();
int mediaLength = cn.getContentLength();
if (is == null) {
return;
}
deleteTempFile(true);
DLTempFile = File.createTempFile(TEMP_DOWNLOAD_FILE_NAME,
FILE_POSTFIX);
out = new FileOutputStream(DLTempFile);
byte buf[] = new byte[PER_READ];
int readLength = 0;
while (readLength != -1 && !stop) {
if (pause) {
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
e.printStackTrace();
}
continue;
}
readLength = is.read(buf);
if (readLength > 0) {
try {
out.write(buf, 0, readLength);
totalKbRead += readLength;
} catch (Exception e) {
Log.e(TAG, e.toString());
}
}
dealWithBufferData();
}
if (totalKbRead == mediaLength) {
downloadOver = true;
dealWithLastData();
// 删除临时文件
if (DLTempFile != null && DLTempFile.exists()) {
DLTempFile.delete();
}
}
} catch (MalformedURLException e) {
Log.e(TAG, e.toString());
} catch (IOException e) {
Log.e(TAG, e.toString());
} finally {
if (out != null) {
try {
out.close();
} catch (IOException e) {
e.printStackTrace();
}
}
if (is != null) {
try {
is.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
private boolean downloadOver = false;
private boolean wasPlayed = false;
private void dealWithBufferData() {
if (mPlayer == null || !wasPlayed) {
if (totalKbRead >= MIN_BUFF) {
try {
startMediaPlayer();
} catch (Exception e) {
}
}
} else if (mPlayer.getDuration() - mPlayer.getCurrentPosition() <= 1000) {
deleteTempFile(true);
transferBufferToMediaPlayer();
}
}
private void startMediaPlayer() {
try {
deleteTempFile(true);
BUFFTempFile = File.createTempFile(TEMP_BUFF_FILE_NAME,
FILE_POSTFIX);
FileSystemUtil.copyFile(DLTempFile, BUFFTempFile);
mPlayer = new MediaPlayer();
setListener();
mPlayer.setDataSource(BUFFTempFile.getAbsolutePath());
mPlayer.prepare();
mPlayer.start();
wasPlayed = true;
} catch (IOException e) {
}
}
private void transferBufferToMediaPlayer() {
try {
boolean wasPlaying = mPlayer.isPlaying();
int curPosition = mPlayer.getCurrentPosition();
mPlayer.pause();
BUFFTempFile = File.createTempFile(TEMP_BUFF_FILE_NAME,
FILE_POSTFIX);
FileSystemUtil.copyFile(DLTempFile, BUFFTempFile);
mPlayer = new MediaPlayer();
mPlayer.setDataSource(BUFFTempFile.getAbsolutePath());
mPlayer.prepare();
mPlayer.seekTo(curPosition);
boolean atEndOfFile = mPlayer.getDuration()
- mPlayer.getCurrentPosition() <= 1000;
if (wasPlaying || atEndOfFile) {
mPlayer.start();
}
} catch (Exception e) {
}
}
private void dealWithLastData() {
Runnable updater = new Runnable() {
public void run() {
transferBufferToMediaPlayer();
}
};
handler.post(updater);
}
public void onCompletion(MediaPlayer mp) {
if (mHandler != null) {
mHandler.sendEmptyMessage(Preferences.MEDIA_ENDED);
}
}
public boolean onError(MediaPlayer mediaPlayer, int what, int extra) {
if (mediaPlayer != null) {
mediaPlayer.stop();
mediaPlayer.release();
}
if (mHandler != null) {
mHandler.sendEmptyMessage(Preferences.MEDIA_ERROR);
}
return true;
}
public void onBufferingUpdate(MediaPlayer arg0, int percent) {
Log.d(TAG, "onBufferingUpdate called ---> percent:" + percent);
if (mHandler != null) {
mHandler.sendEmptyMessage(Preferences.EMDIA_BUFF_CHANGE);
}
}
private class PlayThread extends Thread {
private String url;
PlayThread(String url) {
this.url = url;
}
public void run() {
if (!URLUtil.isNetworkUrl(url)) {
mPlayer = new MediaPlayer();
setListener();
try {
// if (url.startsWith("content://")) {
// mPlayer.setDataSource(MediaPlayService.this, Uri
// .parse(url));
// } else {
mPlayer.setDataSource(url);
// }
mPlayer.setAudioStreamType(AudioManager.STREAM_MUSIC);
setVolume(0f);
mPlayer.prepare();
mPlayer.start();
} catch (IllegalArgumentException e) {
Log.e(TAG, e.toString());
} catch (IllegalStateException e) {
Log.e(TAG, e.toString());
} catch (IOException e) {
Log.e(TAG, e.toString());
}
} else {
playFromNet(url, 0, UNKNOWN_LENGTH);
}
}
}
}
