How to retrieve and play mp3 files from Parse.com

问题

I'm developing an app in which you can record an audio clip, upload it into a database on Parse.com and then retrieve the audio clip from Parse.com and play it.

I'm able to record and upload the audio file on Parse.com, but I don't know what to do about the last step! Here you can see how I save and store the audio clip on Parse.com:

byte[] data = outputFile.getBytes();
       //ParseUser currentUser = ParseUser.getCurrentUser();
       //String usernameText = currentUser.getUsername();
       Calendar c = Calendar.getInstance(); 
       String mUploadName = c.get(Calendar.SECOND) + "_recording.mp3";
       ParseFile file = new ParseFile(mUploadName, data);
       file.saveInBackground();
       // _PostStructure is the class where I've wrote the "set" and "get" methods to use the database on Parse.com
       _PostStructure new_audiofile = new _PostStructure();
       new_audiofile.setAudioFile(file);
       new_audiofile.saveInBackground();

And this is my try to retrieve and play the audio clip from Parse.com:

mediaPlayer = new MediaPlayer();
       ParseQuery<ParseObject> query = ParseQuery.getQuery("MyClass");
       query.getInBackground("jZAetQnISj", new GetCallback<ParseObject>() {

            public void done(ParseObject recording, com.parse.ParseException e) {
                   if (e != null) { 
                       //do nothing
                   }
                   else {
                        ParseFile audioFile = recording.getParseFile("AudioFile"); 
                        String audioFileURL = audioFile.getUrl();
                        mediaPlayer = new MediaPlayer();
                        mediaPlayer.setAudioStreamType(AudioManager.STREAM_MUSIC);
                        try {
                            mediaPlayer.setDataSource(audioFileURL);
                            mediaPlayer.prepare();
                              mediaPlayer.start();
                              text.setText("Recording Point: Playing");

                              finalTime = mediaPlayer.getDuration();
                              startTime = mediaPlayer.getCurrentPosition();
                              if(oneTimeOnly == 0){
                                 seekbar.setMax((int) finalTime);
                                 oneTimeOnly = 1;
                              } 

                              endTimeField.setText(String.format("%d min, %d sec", 
                                 TimeUnit.MILLISECONDS.toMinutes((long) finalTime),
                                 TimeUnit.MILLISECONDS.toSeconds((long) finalTime) - 
                                 TimeUnit.MINUTES.toSeconds(TimeUnit.MILLISECONDS.
                                 toMinutes((long) finalTime)))
                              );
                              startTimeField.setText(String.format("%d min, %d sec", 
                                 TimeUnit.MILLISECONDS.toMinutes((long) startTime),
                                 TimeUnit.MILLISECONDS.toSeconds((long) startTime) - 
                                 TimeUnit.MINUTES.toSeconds(TimeUnit.MILLISECONDS.
                                 toMinutes((long) startTime)))
                              );
                              seekbar.setProgress((int)startTime);
                              myHandler.postDelayed(UpdateSongTime,100);
                              pauseButton.setEnabled(true);
                              playButton.setEnabled(false);
                        } catch (IllegalArgumentException e1) {
                            // TODO Auto-generated catch block
                            e1.printStackTrace();
                        } catch (SecurityException e1) {
                            // TODO Auto-generated catch block
                            e1.printStackTrace();
                        } catch (IllegalStateException e1) {
                            // TODO Auto-generated catch block
                            e1.printStackTrace();
                        } catch (IOException e1) {
                            // TODO Auto-generated catch block
                            e1.printStackTrace();
                        }        
                    }
            }
       });

So, when I record an audio clip and save it on Parse.com, everything works fine. When I touch the "play" button, the app doesn't crash, but no sound is played. Can you help me to find the mistake?

回答1:

Finally I've got the solution! :) This was my mistake:

       byte[] data = outputFile.getBytes();

The object that I was trying to convert into a byte array (outputFile) was not the mp3 file, but the resource path of the file (/storage/sdcard0/audiocapturetest.mp3), so it was basically a string!
If you want to save an mp3 file on Parse.com, this is the right code:

       FileInputStream fileInputStream = null;
       File fileObj = new  File(outputFile);
       byte[] data = new byte[(int) fileObj.length()];

       try {
           //convert file into array of bytes
        fileInputStream = new FileInputStream(fileObj);
        fileInputStream.read(data);
        fileInputStream.close();
       } catch(Exception e) {
        e.printStackTrace();
       }

       Calendar c = Calendar.getInstance(); 
       mUploadName = c.get(Calendar.SECOND) + "_recording.mp3";
       ParseFile file = new ParseFile(mUploadName, data);
       file.saveInBackground();
       _PostStructure new_audiofile = new _PostStructure();
       new_audiofile.setNome(mUploadName);
       new_audiofile.setAudioFile(file);
       new_audiofile.saveInBackground();

I hope it can be helpful to you! :)

EDIT
I uploaded an example on github, you can find it at https://github.com/fullwipe/ParseAudioFileExample

来源：https://stackoverflow.com/questions/27219822/how-to-retrieve-and-play-mp3-files-from-parse-com