本文介绍的是mediaplayer实现边下边播的一种方法。
原理：创建两个socket服务，远程socket和本地socket，远程socket用于请求播放资源真实的数据，本地socket用于监听mediaplayer请求，并且将远程socket获取到的数据，写到mediaplyer中进行播放。
为什么需要采用两个socket?
如果只采用一个socket代理，歌曲可以播放正常，但是mediaplayer的seekTo方法失效，原因是mediaplayer在请求数据的时候缺少了一些请求数据，导致mediaPlayer的duration一直为0，所以无法进行seekTo操作。
详细步骤：
一，初始化本地socket代理
public MediaPlayerProxy(String writeFileName, boolean writeFile) throws Exception {
proxyIdle = false;
this.writeFile = writeFile;
this.writeFileName = writeFileName;
try {
if (localServer == null || localServer.isClosed()) {
//创建本地socket服务器，用来监听mediaplayer请求和给mediaplayer提供数据
localServer = new ServerSocket();
localServer.setReuseAddress(true);
InetSocketAddress socketAddress = new InetSocketAddress(InetAddress.getByName(LOCAL_IP_ADDRESS), local_ip_port);
localServer.bind(socketAddress);
}
} catch (Exception e) {
LogTool.ex(e);
try {
local_ip_port--;
localServer = new ServerSocket(local_ip_port, 0, InetAddress.getByName(LOCAL_IP_ADDRESS));
localServer.setReuseAddress(true);
} catch (Exception e2) {
LogTool.ex(e2);
throw new Exception();
}
}
}
二、根据真实的请求音源地址，得到本地的音源地址，将本地音源地址通过setDataSource的方式传递给mediaplayer. 前面创建的本地socket对象监听这个地址，用于获取mediaplayer的请求数据。
public String getLocalURLAndSetRemotSocketAddr(String url) {
try {
//真实的播放地址
remotUrl = url;
if (writeFile) {
bufferingMusicUrlList.add(remotUrl);
}
String localProxyUrl = "";
final URI originalURI = URI.create(url);
final String remoteHost = originalURI.getHost();
if (!TextUtils.isEmpty(remoteHost)) {
if (originalURI.getPort() != -1) {//URL带Port
new Thread(new Runnable() {
@Override
public void run() {
remoteAddress = new InetSocketAddress(remoteHost, originalURI.getPort());
}
}).start();
//将真实的播放地址替换成本地的代理地址
localProxyUrl = url.replace(remoteHost + ":" + originalURI.getPort(), LOCAL_IP_ADDRESS + ":" + local_ip_port);
remoteHostAndPort = remoteHost + ":" + originalURI.getPort();
} else {//URL不带Port
if (!TextUtils.isEmpty(remoteHost)) {
new Thread(new Runnable() {
@Override
public void run() {
remoteAddress = new InetSocketAddress(remoteHost, HTTP_PORT);//使用80端口
}
}).start();
//将真实的播放地址替换成本地的代理地址
localProxyUrl = url.replace(remoteHost, LOCAL_IP_ADDRESS + ":" + local_ip_port);
remoteHostAndPort = remoteHost;
}
}
}
return localProxyUrl;
} catch (Exception e) {
LogTool.ex(e);
return "";
}
}
三、本地socket监听mediaplayer,通过getInputStream方法可以获取到mediaplayer传递过来的请求信息数据，由于我们是通过本地代理地址的方式获取到的，所以我们需要根据这个本地的请求信息替换成真实的远程socket请求信息，向服务器获取真实请求数据。
public void getTrueSocketRequestInfo(Socket localSocket) throws Exception {
InputStream in_localSocket = localSocket.getInputStream();
String trueSocketRequestInfoStr = "";//保存MediaPlayer的真实HTTP请求
byte[] local_request = new byte[1024];
while (in_localSocket.read(local_request) != -1) {
String str = new String(local_request);
trueSocketRequestInfoStr = trueSocketRequestInfoStr + str;
if (trueSocketRequestInfoStr.contains("GET") && trueSocketRequestInfoStr.contains("\r\n\r\n")) {
//把request中的本地ip改为远程ip
trueSocketRequestInfoStr = trueSocketRequestInfoStr.replace(LOCAL_IP_ADDRESS + ":" + local_ip_port, remoteHostAndPort);
this.trueSocketRequestInfoStr = trueSocketRequestInfoStr;
//如果用户拖动了进度条，因为拖动了滚动条还有Range则表示本地歌曲还未缓存完，不再保存
if (trueSocketRequestInfoStr.contains("Range")) {
LogTool.s("=Range=");
writeFile = false;
}
break;
}
}
}
四、 上一步我们获取到了真实的请求数据信息，此时通过远程socket连接远程请求。
public Socket sendRemoteRequest() throws Exception {
//创建远程socket用来请求网络数据
Socket remoteSocket = new Socket();
remoteSocket.connect(remoteAddress, socketTimeoutTime);
remoteSocket.getOutputStream().write(trueSocketRequestInfoStr.getBytes());
remoteSocket.getOutputStream().flush();
return remoteSocket;
}
五、将远程socket的数据，通过本地socket写入mediaplayer进行播放。
public void processTrueRequestInfo(Socket remoteSocket, Socket localSocket) {
//如果要写入本地文件的实例声明
FileOutputStream fileOutputStream = null;
File theFile = null;
try {
//获取音乐网络数据
InputStream in_remoteSocket = remoteSocket.getInputStream();
if (in_remoteSocket == null) return;
OutputStream out_localSocket = localSocket.getOutputStream();
if (out_localSocket == null) return;
//如果要写入文件，配置相关实例
if (writeFile) {
File dirs = new File(Environment.getExternalStorageDirectory() + File.separator + "clearlee_music");
dirs.mkdirs();
theFile = new File(dirs + File.separator + writeFileName + ".m4a");
fileOutputStream = new FileOutputStream(theFile);
}
try {
int readLenth;
byte[] remote_reply = new byte[4096];
boolean firstData = true;//是否循环中第一次获得数据
//当从远程还能取到数据且播放器还没切换另一首网络音乐
while ((readLenth = in_remoteSocket.read(remote_reply, 0, remote_reply.length)) != -1 && currProxyId == lastProxyId) {
//首先从数据中获得文件总长度
try {
if (firstData) {
firstData = false;
String str = new String(remote_reply, "utf-8");
Pattern pattern = Pattern.compile("Content-Length:\\s*(\\d+)");
Matcher matcher = pattern.matcher(str);
if (matcher.find()) {
//获取数据的大小
fileTotalLength = Long.parseLong(matcher.group(1));
}
}
} catch (Exception e) {
LogTool.ex(e);
}
//把远程sokcet拿到的数据用本地socket写到mediaplayer中播放
try {
out_localSocket.write(remote_reply, 0, readLenth);
out_localSocket.flush();
} catch (Exception e) {
LogTool.ex(e);
}
//计算当前播放时，其在seekbar上的缓冲值,并刷新进度条
try {
cachedFileLength += readLenth;
if (fileTotalLength > 0 && currProxyId == lastProxyId) {
currMusicCachedProgress = (int) (Common.div(cachedFileLength, fileTotalLength, 5) * 100);
if (mOnCaChedProgressUpdateListener != null && currMusicCachedProgress <= 100) {
mOnCaChedProgressUpdateListener.updateCachedProgress(currMusicCachedProgress);
}
}
} catch (Exception e) {
LogTool.ex(e);
}
//如果需要缓存数据到本地，就缓存到本地
if (writeFile) {
try {
if (fileOutputStream != null) {
fileOutputStream.write(remote_reply, 0, readLenth);
fileOutputStream.flush();
}
} catch (Exception e) {
LogTool.ex(e);
}
}
}
//如果是因为切换音乐跳出循环的，当前音乐播放进度，小于 seekbar最大值的1/4,就把当前音乐缓存在本地的数据清除了
if (currProxyId != lastProxyId && currPlayDegree < 25) {
bufferingMusicUrlList.remove(remotUrl);
if (theFile != null) {
Common.deleteFile(theFile.getPath());
}
}
} catch (Exception e) {
LogTool.ex(e);
if (theFile != null) {
Common.deleteFile(theFile.getPath());
}
bufferingMusicUrlList.remove(remotUrl);
} finally {
in_remoteSocket.close();
out_localSocket.close();
if (fileOutputStream != null) {
fileOutputStream.close();
//音频文件缓存完后处理
if (theFile != null && Common.checkFileExist(theFile.getPath())) {
conver2RightAudioFile(theFile);
if (musicControlInterface != null) {
musicControlInterface.updateBufferFinishMusicPath(musicKey, theFile.getPath());
bufferingMusicUrlList.remove(remotUrl);
}
}
}
localSocket.close();
remoteSocket.close();
}
} catch (Exception e) {
LogTool.ex(e);
if (theFile != null) {
Common.deleteFile(theFile.getPath());
}
bufferingMusicUrlList.remove(remotUrl);
}
}
至此，mediaplayer便实现了边下边播的功能。
详细代码已上传至github，地址：https://github.com/Clearlee/PlayWhileDownloadMusic
