在服务类中使用MediaPlayer ...？

Question

I'm making an app, and currently I'm working on adding background music to it. I've seen a lot of ways to do that, and I've chosen to make it using a Service. My problem, however, comes when I call that Service, due to I hear nothing, the music doesn't play! I've compared with another examples, and tried almost everything, but there's no change...Instead meanwhile I'm using an IntentService to play the music (to have at least something), but it isn't pretty good, cos for example when I press the home button, the music continues playing...

The code of the Service Class is the following:

    package edu.ub.pis2016.darmas.entrega1;


    import android.app.Service;
    import android.content.Context;
    import android.content.Intent;
    import android.media.AudioManager;
    import android.media.MediaPlayer;
    import android.os.IBinder;
    import android.widget.Toast;


    public class Service_1 extends Service {

        MediaPlayer player;


        public IBinder onBind(Intent arg0) {

            return null;
        }

        @Override
        public void onCreate(){
            super.onCreate();
            player = MediaPlayer.create(this, R.raw.calm);
            player.setLooping(true); // Set looping
            player.setVolume(100,100);
        }

        @Override
        public int onStartCommand(Intent intent, int flags, int startId){
            player.start();

            return 1;
        }


        @Override
        public void onDestroy(){
            player.stop();
            player.release();
            player = null;
        }


        public void onStop(){
            player.stop();
        }

        public void onPause(){

        }


    }

and I call the Service from one of my activities, by doing:

Intent intent = new Intent(this, Service_1.class);
startService(intent);

But doesn't work... Instead, here's my code of the IntentService class:

    package edu.ub.pis2016.darmas.entrega1;

    import android.app.IntentService;
    import android.content.Context;
    import android.content.Intent;
    import android.media.AudioManager;
    import android.media.MediaPlayer;
    import android.os.IBinder;
    import android.view.KeyEvent;
    import android.widget.Toast;

    /*
    *  Service_music Class which extends from IntentService class. We do   this    due to with this latter,
    *  there's no need to implement a thread thanks to it creates by  default (a worker thread),
    *  which runs in the background. Also, this class implements from  Audiomanager, in order to
    *  control the different situations in where the music can be found  through the phone.
    *
    */
    public class Service_music extends IntentService implements AudioManager.OnAudioFocusChangeListener {

        MediaPlayer mp;
        AudioManager audioManager;
        boolean end = false;



        /*
        *  ------------------------------------------------
        *  -            Class Itself Methods              -
        *  ------------------------------------------------
        */

        // Constructor class, required! We create here our worker thread
        public Service_music() {
            super("Service_music_thread");
        }


        public IBinder onBind(Intent arg0) {

            return null;
        }

        @Override
        protected void onHandleIntent(Intent intent) {

            lets_play_music();
            while (end != true){}
        }


        @Override
        public void onDestroy(){
            super.onDestroy(); // It's mandatory to call the super() methods when extending from IntentService
            if (this.mp != null) releaseMediaPlayer();

        }


        /*
        *  ------------------------------------------------
        *  -             Initialize Methods               -
        *  ------------------------------------------------
        */

        // Method to initialize the media player
        private void initializeMediaPlayer(){
            //this.mp = MediaPlayer.create(this, R.raw.calm);
            this.mp = MediaPlayer.create(this, R.raw.barefootandbruisdjamestownstory);
            this.mp.setLooping(true);
            this.mp.start();
        }


        private void initializeAudioManager(){
            this.audioManager = (AudioManager) getSystemService(Context.AUDIO_SERVICE);
            int result = audioManager.requestAudioFocus(this, AudioManager.STREAM_MUSIC,
            AudioManager.AUDIOFOCUS_GAIN);

            if (result != AudioManager.AUDIOFOCUS_REQUEST_GRANTED) {
                // could not get audio focus.
                Toast.makeText(getApplicationContext(), "Ha habido un error al iniciar la musica :(", Toast.LENGTH_SHORT).show();
            }
        }

        /*
        *  ------------------------------------------------
        *  -               Auxiliar Methods               -
        *  ------------------------------------------------
        */

        // This method will carry the task of playing the music, but notice this is only for local media!
        private void lets_play_music(){
            initializeAudioManager();
            initializeMediaPlayer();
            //initializeAudioManager();
            //this.mp.start();
        }


        // Method to release all resources taken by the mp object
        private void releaseMediaPlayer(){
            this.mp.stop();
            this.mp.release();
            this.mp = null;
        }


        /*
        *  ------------------------------------------------
        *  -            Audio Manager Methods             -
        *  ------------------------------------------------
        */

        public void onAudioFocusChange(int focusChange) {
            // Do something based on focus change...
            switch (focusChange){

                // Case if we have gained the focus to play!
                case AudioManager.AUDIOFOCUS_GAIN:
                    if (this.mp == null) initializeMediaPlayer(); // If we had to release the mp by any reason, we re-initialize it!
                    else if(!this.mp.isPlaying()) {
                       this.mp.setLooping(true);  // In theory, it should play looping through infinitely
                       this.mp.start(); // If it's not currently playing, starts!
                    }
                    this.mp.setVolume(1.0f, 1.0f);  // We set the volume!
                    break;

                // Case if we have completely (or almost) lost the focus
                case AudioManager.AUDIOFOCUS_LOSS:
                    if (this.mp.isPlaying()) this.mp.stop(); // If it's currently playing, we have to stop it first
                    end = true;
                    releaseMediaPlayer();  // We release the resources
                    break;

               // Case if we have lost the focus for a short period of time
                case AudioManager.AUDIOFOCUS_LOSS_TRANSIENT:
                    if (this.mp.isPlaying()) this.mp.pause(); // If it's currently playing, we just pause it!
                    break;

                // Case if we have lost the focus but for a tiny piece of time, so we're allowed to continue performing the music but in a quiet state!
                case AudioManager.AUDIOFOCUS_LOSS_TRANSIENT_CAN_DUCK:
                    if (this.mp.isPlaying()) this.mp.setVolume(0.3f, 0.3f); // If it's currently playing, we just set the volume to a quiet level!
                    break;
            }
        }


    }

This latter works, but not the 'AudioManager', and when I press the 'home button' the music continues playing...

If someone could help me, or tell me where is the error, or what I'm doing bad, to fix this, I'd be extremely grateful, because I'm turning mad with this...

Answer 1

Two guesses (due to lack of full code):

Your manifest doesn't contain the service, so it doesn't receive the intent R.raw.value doesn't exist