MediaPlayer可在模拟器上运行，但不能在android中的实际设备上运行

Question

I am creating an application where music is streaming from direct link. It is working with emulator but not working on actual device. I created a class named HomeFragment and a nested class Player which extends AsyncTask and initailized MediaPlayer. It looks like that there is error on intantiating MediaPlayer. In the logcat it shows prepare() failed.

I have searched for it and found Attempt to call getDuration without a valid mediaplayer in media player on android ,but this is defferent because i am not getting error because of getDuration() method

    public class HomeFragment extends Fragment {
View view;

private ImageButton btn_play_pause;
private TextView tv_time;
private SeekBar seekBar;
private MediaPlayer mediaPlayer;
private int mediaFileLength;
private int realTimeLength;
private boolean playPause;
private boolean initialStage = true;
private ProgressDialog progressDialog;
final Handler handler = new Handler();
private Runnable updater;

@Nullable
@Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, Bundle savedInstanceState) {
    view = inflater.inflate(R.layout.home_fragment,container,false);
    initialize();
    return view;
}

private void initialize() {
    btn_play_pause = (ImageButton) view.findViewById(R.id.btn_play_pause);
    tv_time = (TextView) view.findViewById(R.id.tv_timer);
    seekBar = (SeekBar) view.findViewById(R.id.seekBar);
    seekBar.setMax(99);
    seekBar.setOnTouchListener(new View.OnTouchListener() {
        @Override
        public boolean onTouch(View v, MotionEvent event) {
            if(mediaPlayer.isPlaying()){
                SeekBar seekbar = (SeekBar) v;
                int playPosition = (mediaFileLength / 100) * seekbar.getProgress();
                mediaPlayer.seekTo(playPosition);
            }
            return false;
        }
    });

    mediaPlayer = new MediaPlayer();
    progressDialog = new ProgressDialog(view.getContext());
    btn_play_pause.setOnClickListener(new View.OnClickListener(){
        @Override
        public void onClick(View v) {
            if(!playPause){
                btn_play_pause.setImageResource(R.drawable.ic_pause);
                if(initialStage){
                    new Player().execute("http://www.url_of_song.mp3");
                }
                else {
                    if (mediaPlayer != null) {
                        if (!mediaPlayer.isPlaying()) {
                            mediaPlayer.start();
                        }
                    }
                }
                playPause = true;
            }
            else{
                btn_play_pause.setImageResource(R.drawable.ic_play);
                if(mediaPlayer != null) {
                    if (mediaPlayer.isPlaying()) {
                        mediaPlayer.pause();
                    }
                }
                playPause = false;
            }
        }
    });
}

class Player extends AsyncTask<String, Void, Boolean>{

    @Override
    protected Boolean doInBackground(String... params) {
        boolean prepared = false;

        try{
            mediaPlayer.setDataSource(params[0]);
            mediaPlayer.setOnBufferingUpdateListener(new MediaPlayer.OnBufferingUpdateListener() {
                @Override
                public void onBufferingUpdate(MediaPlayer mp, int percent) {
                    seekBar.setSecondaryProgress(percent);
                }
            });

            mediaPlayer.setOnCompletionListener(new MediaPlayer.OnCompletionListener(){

                @Override
                public void onCompletion(MediaPlayer mp) {
                    initialStage = true;
                    playPause = false;
                    btn_play_pause.setImageResource(R.drawable.ic_pause);
                    mp.stop();
                    mp.reset();
                }
            });
            mediaPlayer.prepare();
            prepared = true;
        }
        catch (Exception e){
            Log.e("AudioStreaming", e.getMessage());
            prepared = false;
        }
        return prepared;
    }

    @Override
    protected void onPreExecute() {
        super.onPreExecute();
        progressDialog.setMessage("Please Wait...");
        progressDialog.show();
    }

    @Override
    protected void onPostExecute(Boolean aBoolean) {
        super.onPostExecute(aBoolean);
        if(progressDialog.isShowing()){
            progressDialog.cancel();
        }
   //     mediaFileLength = mediaPlayer.getDuration();
        realTimeLength = mediaFileLength;
        mediaPlayer.start();
        initialStage = false;
        updateSeekbar();
    }
}

private void updateSeekbar(){
    seekBar.setProgress((int)(((float)mediaPlayer.getCurrentPosition() / mediaFileLength)*100));
    if(mediaPlayer.isPlaying()){
        updater = new Runnable() {
            @Override
            public void run() {
                updateSeekbar();
                realTimeLength -= 1000;
                tv_time.setText(String.format("%d:%d", TimeUnit.MILLISECONDS.toMinutes(realTimeLength), TimeUnit.MILLISECONDS.toSeconds(realTimeLength) - TimeUnit.MINUTES.toSeconds(TimeUnit.MILLISECONDS.toMinutes(realTimeLength))));
            }
        };
        handler.postDelayed(updater, 1000);
    }
}

What i am doing wrong, what is the error, The Logcat shows:

    02-03 15:54:27.226 15845-15845/com.example.sk.voiceapplication I/ViewRootImpl: CPU Rendering VSync enable = true
02-03 15:54:27.266 15845-15864/com.example.sk.voiceapplication D/MediaHTTPConnection: filterOutInternalHeaders: key=User-Agent, val= stagefright/1.2 (Linux;Android 5.1.1)
02-03 15:54:27.266 15845-15991/com.example.sk.voiceapplication D/MediaHTTPConnection: proxy null port 0
02-03 15:54:29.496 15845-15864/com.example.sk.voiceapplication D/MediaHTTPConnection: proxy null port 0
02-03 15:54:33.126 15845-15863/com.example.sk.voiceapplication D/MediaHTTPConnection: filterOutInternalHeaders: key=User-Agent, val= stagefright/1.2 (Linux;Android 5.1.1)
02-03 15:54:33.126 15845-15991/com.example.sk.voiceapplication D/MediaHTTPConnection: proxy null port 0
02-03 15:54:36.926 15845-15864/com.example.sk.voiceapplication D/MediaHTTPConnection: filterOutInternalHeaders: key=User-Agent, val= stagefright/1.2 (Linux;Android 5.1.1)
02-03 15:54:36.926 15845-15863/com.example.sk.voiceapplication D/MediaHTTPConnection: proxy null port 0
02-03 15:54:40.486 15845-15864/com.example.sk.voiceapplication D/MediaHTTPConnection: filterOutInternalHeaders: key=User-Agent, val= stagefright/1.2 (Linux;Android 5.1.1)
02-03 15:54:40.486 15845-15863/com.example.sk.voiceapplication D/MediaHTTPConnection: proxy null port 0
02-03 15:54:44.326 15845-15991/com.example.sk.voiceapplication D/MediaHTTPConnection: filterOutInternalHeaders: key=User-Agent, val= stagefright/1.2 (Linux;Android 5.1.1)
02-03 15:54:44.336 15845-15864/com.example.sk.voiceapplication D/MediaHTTPConnection: proxy null port 0
02-03 15:54:48.176 15845-15864/com.example.sk.voiceapplication D/MediaHTTPConnection: filterOutInternalHeaders: key=User-Agent, val= stagefright/1.2 (Linux;Android 5.1.1)
02-03 15:54:48.176 15845-15863/com.example.sk.voiceapplication D/MediaHTTPConnection: proxy null port 0
02-03 15:54:51.696 15845-15863/com.example.sk.voiceapplication D/MediaHTTPConnection: filterOutInternalHeaders: key=User-Agent, val= stagefright/1.2 (Linux;Android 5.1.1)
02-03 15:54:51.696 15845-15991/com.example.sk.voiceapplication D/MediaHTTPConnection: proxy null port 0
02-03 15:54:55.526 15845-15863/com.example.sk.voiceapplication D/MediaHTTPConnection: filterOutInternalHeaders: key=User-Agent, val= stagefright/1.2 (Linux;Android 5.1.1)
02-03 15:54:55.526 15845-15991/com.example.sk.voiceapplication D/MediaHTTPConnection: proxy null port 0
02-03 15:54:59.366 15845-15863/com.example.sk.voiceapplication D/MediaHTTPConnection: filterOutInternalHeaders: key=User-Agent, val= stagefright/1.2 (Linux;Android 5.1.1)
02-03 15:54:59.366 15845-15991/com.example.sk.voiceapplication D/MediaHTTPConnection: proxy null port 0
02-03 15:55:03.206 15845-15864/com.example.sk.voiceapplication D/MediaHTTPConnection: filterOutInternalHeaders: key=User-Agent, val= stagefright/1.2 (Linux;Android 5.1.1)
02-03 15:55:03.206 15845-15863/com.example.sk.voiceapplication D/MediaHTTPConnection: proxy null port 0
02-03 15:55:07.046 15845-15991/com.example.sk.voiceapplication D/MediaHTTPConnection: filterOutInternalHeaders: key=User-Agent, val= stagefright/1.2 (Linux;Android 5.1.1)
02-03 15:55:07.046 15845-15864/com.example.sk.voiceapplication D/MediaHTTPConnection: proxy null port 0
02-03 15:55:07.886 15845-15991/com.example.sk.voiceapplication D/MediaHTTPConnection: proxy null port 0
02-03 15:55:08.536 15845-15991/com.example.sk.voiceapplication E/MediaPlayer: error (1, -2147483648)
02-03 15:55:08.536 15845-15878/com.example.sk.voiceapplication E/AudioStreaming: Prepare failed.: status=0x1

02-03 15:55:08.566 15845-15845/com.example.sk.voiceapplication E/MediaPlayer: error (-38, 0)
02-03 15:55:08.566 15845-15845/com.example.sk.voiceapplication E/MediaPlayer: start called in state 0
02-03 15:55:08.566 15845-15845/com.example.sk.voiceapplication E/MediaPlayer: error (-38, 0)
02-03 15:55:08.566 15845-15845/com.example.sk.voiceapplication E/MediaPlayer: Error (-38,0)
02-03 15:55:08.566 15845-15845/com.example.sk.voiceapplication E/MediaPlayer: stop called in state 0
02-03 15:55:08.566 15845-15845/com.example.sk.voiceapplication E/MediaPlayer: error (-38, 0)

Answer 1

I'm not sure that this is your entire problem, but I see that you are calling media player.prepare() in the doInBackground method of your AsyncTask, and then calling media player.start() in onPostExecute(),

But you haven't waited for the player to finish initializing after the call to prepare(). You need to use an OnPreparedListener, and wait for that notification before interacting with the player.

Answer 2

I was doing this mistake, the file name of streamed mp3 song in url in new Player().execute("http://www.url_of_song.mp3"); inside onClick method contains spaces and capital letters thus the song couldnt be streamed. So be aware of such silly mistakes.