Android MediaPlayer

//存放当前播放的Url
private String currentPlayUrl;
//文件下载后存放的位置,文件名为Url的md5
private final String downloadPath = PathUtil.getAudioDir( );

//音频播放的回调
private AudioPlayStateCallback audioCallback;
//文件下载的回调
private DownloadFileCallback downloadCallback;

private AudioPlayUtil( )
{
	// TODO Auto-generated constructor stub
}

public static AudioPlayUtil getInstance()
{
	if(instance == null)
	{
		instance = new AudioPlayUtil( );
	}
	return instance;
}


public void playAudio(Context mContext, String url)
{
	playAudio(mContext, url , null );
}

public void playAudio(Context mContext, String url, AudioPlayStateCallback playCallback)
{
	playAudio(mContext, url , playCallback, null );
}

/**
 * 播放音频的接口
 * @param mContext
 * @param url 文件的url
 * @param callback 播放的回调
 * @param downloadCallback 下载的回调
 */
public void playAudio(Context mContext, String url, AudioPlayStateCallback callback, DownloadFileCallback downloadCallback)
{
	if(mediaPlayer == null)
	{
		mediaPlayer = new MediaPlayer( );
		mediaPlayer.setOnCompletionListener( this );
		mediaPlayer.setOnPreparedListener( this );
	}
	

	if(mediaPlayer.isPlaying( ))
	{
		mediaPlayer.stop( );
		mediaPlayer.reset( );
		if(downloadCallback != null)
		{
			downloadCallback.onDownloadFileFinish( 1 , "" , "" );
		}
		if(this.audioCallback != null)
		{
			this.audioCallback.onPlayCompleted( );
		}
		
		
		if(url == currentPlayUrl)
		{

		}else
		{
			currentPlayUrl = url;
			String fileUrl = url;
			this.audioCallback = callback;
			this.downloadCallback = downloadCallback;
			
			if(url.contains( PathUtil.getHTTPPrefix( ) ))
			{
				fileUrl = downloadPath + CryptoUtil.md5( url ) + PathUtil.getMP3Postfix( );
			}
			
			File audioFile = new File( fileUrl );
			if(audioFile.exists( ))
			{
				initMediaPlayer(audioFile.getAbsolutePath( ));
			}else
			{
				//下载
				new DownLoadAuidoThread( mContext, url , this ).start( );
			}
		}
		
	}else
	{
		mediaPlayer.reset( );
		if(downloadCallback != null)
		{
			downloadCallback.onDownloadFileFinish( 1 , "" , "" );
		}
		
		String fileUrl = url;
		currentPlayUrl = url;
		this.audioCallback = callback;
		this.downloadCallback = downloadCallback;
		
		if(url.contains( PathUtil.getHTTPPrefix( ) ))
		{
			fileUrl = downloadPath + CryptoUtil.md5( url ) + PathUtil.getMP3Postfix( );
		}
		
		File audioFile = new File( fileUrl );
		if(audioFile.exists( ))
		{
			initMediaPlayer(fileUrl);
		}else
		{
			//下载
			new DownLoadAuidoThread( mContext, url , this ).start( );
		}
	}

}


private void initMediaPlayer(String url)
{
	try
	{
		mediaPlayer.setDataSource( url );
		mediaPlayer.prepareAsync( );
	}catch (Exception e) {
		// TODO: handle exception
		if(audioCallback != null)
		{
			audioCallback.OnPlayError( );
			resetConfig();
		}
	}
	
}

@Override
public void onPrepared( MediaPlayer mp )
{
	// TODO Auto-generated method stub
	mp.start( ); 
	if(audioCallback != null)
	{
		audioCallback.OnPlayStarted( );
	}
}

@Override
public void onCompletion( MediaPlayer mp )
{
	// TODO Auto-generated method stub
	if(audioCallback != null)
	{
		audioCallback.onPlayCompleted( );
	}
}

private void resetConfig()
{
	
	audioCallback = null;
	downloadCallback = null;
	if(mediaPlayer!=null)
	{
		mediaPlayer.reset( );
	}
}

public void releaseRes()
{
	if(mediaPlayer!=null)
	{
		mediaPlayer.release( );
		mediaPlayer = null;
	}
}

@Override
public void onDownloadFileProgress( long lenghtOfFile , long LengthOfDownloaded , int flag )
{
	// TODO Auto-generated method stub
	if(downloadCallback != null && flag == currentPlayUrl.hashCode( ))
	{
		downloadCallback.onDownloadFileProgress( lenghtOfFile , LengthOfDownloaded , flag );
	}
}

@Override
public void onDownloadFileFinish( int flag , String fileName , String savePath )
{
	// TODO Auto-generated method stub
	
	String completedFileName = "";
	if(fileName.contains( PathUtil.getTMPPostfix( ) ))
	{
		int endIndex = fileName.lastIndexOf( PathUtil.getTMPPostfix( ) );
		completedFileName = ( String ) fileName.subSequence( 0 , endIndex ) + PathUtil.getMP3Postfix( );
		File tmpFile = new File( savePath + fileName );
		final File completedFile = new File( savePath + completedFileName );
		try
		{
			completedFile.createNewFile( );
		}
		catch ( IOException e )
		{
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		if(tmpFile.exists( ))
		{
			boolean isSuccess = tmpFile.renameTo( completedFile );
		}
		
		if(downloadCallback != null && flag == currentPlayUrl.hashCode( ))
		{
			if(completedFile.exists( ))
			{
				initMediaPlayer( completedFile.getAbsolutePath( ) );
			}
			
			downloadCallback.onDownloadFileFinish( flag , completedFileName , savePath );
		}
	}
}

@Override
public void onDownloadFileError( int flag , String fileName , String savePath )
{
	// TODO Auto-generated method stub
	if(downloadCallback != null)
	{
		downloadCallback.onDownloadFileError( flag , fileName , savePath );
	}
	
}

//音频播放的回调
public interface AudioPlayStateCallback
{
	/**开始播放 */
	public void OnPlayStarted();
	
	/**正在播放 */
	public void OnPlayingProgress();
	
	/**正在播放完毕*/
	public void onPlayCompleted();
	
	/**正在播放失败 */
	public void OnPlayError();
}

//Audio下载线程
class DownLoadAuidoThread extends Thread
{
	
	private Context context;
	private DownloadFileCallback callback;
	private String fileUrl;
	
	public DownLoadAuidoThread( Context context , String url , DownloadFileCallback callback )
	{
		// TODO Auto-generated constructor stub
		this.context = context;
		this.callback = callback;
		fileUrl = url;
	}
	
	@Override
	public void run( )
	{
		// TODO Auto-generated method stub
		String fileName = CryptoUtil.md5( fileUrl );
		//临时文件名
		String fileNameTemp = fileName + PathUtil.getTMPPostfix( );
		try
		{ 
			FileDownloadManager manager = new FileDownloadManager( context , callback ,
					fileUrl , fileNameTemp , downloadPath , fileUrl.hashCode( ) );
			manager.run( );
		}
		catch ( ConnectionException e )
		{
			// TODO Auto-generated catch block
			e.printStackTrace( );
		}
		super.run( );
	}
}

@Override
public boolean onError( MediaPlayer mp , int what , int extra )
{
	// TODO Auto-generated method stub
	return false;
} } ```