Stopping Exoplayer onSwipe of ViewPager

Question

I am using a ViewPager with single fragment instance in which I am showing Media files like Images, Videos, Audio.

I have implemented ExoPlayer for handling Video & Audio files. And Glide for images.

To avoid the memory leaks I am releasing the ExoPlayer object like this in ItemViewerFragment.java :

 private void releasePlayer() {
        if (player != null) {
            player.release();
            player = null;
            trackSelector = null;
            simpleExoPlayerView.setPlayer(null);
        }
    }

    @Override
    public void onStart() {
        super.onStart();
        if (player == null && currentGalleryModel != null) {
            initializePlayer();
        }
    }

    @Override
    public void onResume() {
        super.onResume();
        if (player == null && currentGalleryModel != null) {
            initializePlayer();
        }
    }

    @Override
    public void onPause() {
        super.onPause();
        releasePlayer();
    }

    @Override
    public void onStop() {
        super.onStop();
        releasePlayer();
    }

And in onViewCreated() I am initializing view like this :

 @Override
    public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
        super.onViewCreated(view, savedInstanceState);

        if (currentGalleryModel.isVideo() || currentGalleryModel.isAudio()) {

            simpleExoPlayerView.setVisibility(View.VISIBLE);
            imageView.setVisibility(View.GONE);

            initializePlayer();
        } else if (currentGalleryModel.isImage() || currentGalleryModel.isGif()) {
            simpleExoPlayerView.setVisibility(View.GONE);
            imageView.setVisibility(View.VISIBLE);


            Glide.with(this)
                    .load(currentGalleryModel.getFilePath())
                    .placeholder(android.R.color.black)
                    .fitCenter()
                    .diskCacheStrategy(DiskCacheStrategy.NONE)
                    .into(imageView);

        }
    }

I am using FragmentStatePagerAdapeter. This is the getItem method :

@Override
public Fragment getItem(int position) {
    return ItemViewerFragment.newInstance(mItems.get(position));
}

I am not able to detect the onPause of the fragment on first swipe of Viewpager. On second swipe video/audio files are stopped playing.

In activity I have tried adding .addOnPageChangeListener :

@Override
    public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {

     try {
        ((ItemViewerFragment)mAdapter.getItem(mPreviousPos)).imHiddenNow();
        } catch (Exception e) {
            e.printStackTrace();
        }
        mPreviousPos = position;
    }

And in ItemViewerFragment.java :

public void imHiddenNow(){
      releasePlayer();
    }

Still video/audio keeps on playing.

Here is a Video Link to the Screencast.

Demo project GitHub link.

Answer 1

I followed an approach of maintaining HashMap of fragment objects inside PagerAdapter

1. Declare an interface :

interface FragmentLifecycle {
    void onPauseFragment()
}

2. Implement an interface in Fragment.

public void onPauseFragment() {
    if (simpleExoPlayer != null){
        simpleExoPlayer.setPlayWhenReady(false);
    }
}

3. Store all the fragment objects in a HashMap<Integer,Fragment> with there respective positions as a key. Declare hashmap inside PagerAdapter. Also declare one getter method for accessing fragment objects from hashmap. e.g.

   @Override
   public Fragment getItem(int position) {
       ItemViewerFragment fragment = ItemViewerFragment.newInstance(mItems.get(position));
       mFragments.put(position,fragment);
       return fragment;
   }
   

   public ItemViewerFragment getMapItem(int position) { return mFragments.get(position); }

4. In activity where you have declared viewPager keep one variable currentPosition and implement ViewPager.OnPageChangeListener.

5. Inside onPageSelected method,

       @Override
       public void onPageSelected(int position) {
           if(mAdapter.getMapItem(currentPosition) != null) (mAdapter.getMapItem(currentPosition)).onPauseFragment();
           currentPosition = position;
       }