Android在线音乐播放器

Question

i try to build Android online music player that download and play song in same time and user can heard music in download time (before complete download). i use below download class and MediaPlayer to start music but this class just work when download complete and if user click play before complete download application crashed with NullpointExption is there any solution...!???

Download Class ( Resume able) :

public class downloader {
private static boolean Stopdownloader = false;//use for stop download


public static void Stop(boolean status) {
    Stopdownloader = status;
}


public static void dl(final String downloadPath, final String filePath, final Ondownloadprogress lisener) {
    Thread thread = new Thread(new Runnable() {

        @Override
        public void run() {
            try {
                int downloadedSize = 0;
                int fileLength = 0;
                URL url = new URL(downloadPath);
                HttpURLConnection connection = (HttpURLConnection) url.openConnection();
                File file = new File(filePath);
                if (file.exists()) {
                    connection.setRequestProperty("Range", "bytes=" + file.length() + "-");
                    downloadedSize = (int) file.length();
                }
                connection.setRequestMethod("GET");
                connection.setDoInput(true);
                final int FILE_SIZE = connection.getContentLength();
                connection.connect();
                fileLength = connection.getContentLength() + downloadedSize;
                BufferedInputStream input = new BufferedInputStream(connection.getInputStream());
                RandomAccessFile output = new RandomAccessFile(file, "rw");
                output.seek(downloadedSize);

                byte data[] = new byte[1024];
                int count = 0;
                int progress = 0;

                while ((count = input.read(data, 0, 1024)) != -1
                        && progress != 100)
                {
                    if (Stopdownloader) {
                        break;
                    }
                    downloadedSize += count;
                    output.write(data, 0, count);
                    progress = (int) ((downloadedSize * 100) / fileLength);
                    final int ss = (int) ((downloadedSize * 100) / fileLength);
                    final float persent = ((float) progress / FILE_SIZE) * 100;
                    if (lisener != null) {
                        final int finalProgres = progress;
                        G.HANDLER.post(new Runnable() {

                            @Override
                            public void run() {
                                lisener.ondownload((int) ss, finalProgres, FILE_SIZE);
                            }
                        });

                    }
                }

                output.close();
                input.close();
            }
            catch (MalformedURLException e) {}
            catch (IOException e) {}
            finally {}
        }
    });

    thread.start();

}}

and in MainActivity :

    play.setOnClickListener(new OnClickListener() {
        @Override
        public void onClick(View arg0) {
            downloader.dl("http://MUSIC-URL","/temp.mp3", null);
            downloader.Stop(false);
            MediaPlayer Music = MediaPlayer.create(G.context, Uri.parse("/temp.mp3"));
            Music.start();
            Music.prepare();
        }
    });

Answer 1

You need to do the prepare() before the start()

The android reference is pretty well written: http://developer.android.com/reference/android/media/MediaPlayer.html

And take a look at this tutorial, http://sapandiwakar.in/tutorial-how-to-manually-create-android-media-player-controls/ , I think it should move you along a bit as well.