当我再按一次播放按钮，然后在mp3播放器中一次，我的应用程序崩溃

Question

This is fragment activity and i have created a player to play online mp3 it works fine when i hit play button first time and i start the audio and if i pause it pauses.

Problem is when i hit play button more then once application crashes. please help

public class ListenFragment extends Fragment {
    final String url[] = {
            "HTTP://counterexample"};

    private MediaPlayer mediaPlayer;

    @Override
    public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        View rootView = inflater.inflate(fragment_listen, container, false);

        ImageButton btn_play = rootView.findViewById(R.id.btn_play);
        ImageButton btn_pause = rootView.findViewById(R.id.btn_pause);

        mediaPlayer = new MediaPlayer();
        mediaPlayer.setAudioStreamType(AudioManager.STREAM_MUSIC);

        btn_pause.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {

                mediaPlayer.pause();

            }
        });

        btn_play.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {

                try {
                    mediaPlayer.setDataSource(String.valueOf(url[0]));
                } catch (IOException e) {
                    e.printStackTrace();
                }
                try {
                    mediaPlayer.prepare();
                } catch (IOException e) {
                    e.printStackTrace();
                }
                mediaPlayer.start();

            }
        });

        return rootView;
    }
}

here is log cat, please review and answer.

Answer 1

Caution: You must either catch or pass IllegalArgumentException and IOException when using setDataSource(), because the file you are referencing might not exist.

Here is the thing. You must catch IllegalArgumentException too because the file you're trying to load might not be in existence since you're getting it from an online server. Replace your code with the following:

   btn_play.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {

                try {
                    mediaPlayer.setDataSource(String.valueOf(url[0]));
                    mediaPlayer.prepare();
                    mediaPlayer.start();
                } catch (IOException | IllegalArgumentException e) {
                    e.printStackTrace();
                }

            }
        });

Furthermore, I don't know why you're using string array instead of normal string. Read more

---

UPDATE You can show notification in your app bar when the music has started playing using below snippet:

mediaPlayer.setOnCompletionListener(new MediaPlayer.OnCompletionListener() {
            @Override
            public void onCompletion(MediaPlayer mp) {
                if (mp.isPlaying()){
                        //Show notification if music have started play
                        showNotif(context, CHANNEL_ID)
                }
            }
        });


     public void showNotif(Context context, String CHANNEL_ID){
            NotificationCompat.Builder mBuilder = new NotificationCompat.Builder(context, CHANNEL_ID)
                    .setSmallIcon(R.drawable.ic_bubble_notif)
                    .setContentTitle("New Item Remind!")
                    .setAutoCancel(true)
                    .setContentIntent(pendingIntent)
                    .setContentText(context.getString(R.string.notif_msg, reminder.getNumberOfItems()))
                    .setPriority(NotificationCompat.PRIORITY_HIGH);

            createNotificationChannel(context);

            NotificationManagerCompat notificationManager = NotificationManagerCompat.from(context);

            // notificationId is a unique int for each notification that you must define
            notificationManager.notify(0, mBuilder.build());
        }


        private void createNotificationChannel(Context context) {
            // Create the NotificationChannel, but only on API 26+ because
            // the NotificationChannel class is new and not in the support library
            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
                CharSequence name = "CHANEL_NAME";
                String description = "CHANNEL_DESC";
                int importance = NotificationManager.IMPORTANCE_DEFAULT;
                NotificationChannel channel = new NotificationChannel(CHANNEL_ID, name, importance);
                channel.setDescription(description);
                // Register the channel with the system; you can't change the importance
                // or other notification behaviors after this
                NotificationManager notificationManager = context.getSystemService(NotificationManager.class);
                notificationManager.createNotificationChannel(channel);
            }
        }

More on displaying notification in status bar HERE