How to load image using glide in advance?

Question

Actually I'm trying to load images into my reycycleview using glide 4.4.0 and it's loading fine . But now the problem is my recyclerview is lagging a bit when I scroll fast due to the image loading . But I saw some of the glide's method called preload and downloadOnly .So,my question is are these methods helpful for loading image in advance if so then how to use them?

Answer 1

You can use this to fine-tune your preloading. It requires quite a bit of work but looks promising.

In short, you need to create a PreLoader class that will get image URLs from your data set:

private class MyPreloadModelProvider implements PreloadModelProvider {
    @Override
    @NonNull
    public List<U> getPreloadItems(int position) {
      String url = myUrls.get(position);
      if (TextUtils.isEmpty(url)) {
        return Collections.emptyList();
      }
      return Collections.singletonList(url);
    }

    @Override
    @Nullable
    public RequestBuilder getPreloadRequestBuilder(String url) {
        return 
            GlideApp.with(fragment)
              .load(url) 
              .override(imageWidthPixels, imageHeightPixels);
    }
}

And then you set it as a scroll listener on your recycler view:

PreloadSizeProvider sizeProvider = 
    new FixedPreloadSizeProvider(imageWidthPixels, imageHeightPixels);
PreloadModelProvider modelProvider = new MyPreloadModelProvider();
RecyclerViewPreloader<Photo> preloader = 
    new RecyclerViewPreloader<>(
        Glide.with(this), modelProvider, sizeProvider, 10 /*maxPreload*/);

RecyclerView myRecyclerView = (RecyclerView) result.findViewById(R.id.recycler_view);
myRecyclerView.addOnScrollListener(preloader);

After this, you'll get your images preloaded before the onBondViewHolder callback in the adapter, and you'll be able to display them from the cache.

@Override
public void onBindViewHolder(ViewHolder viewHolder, int position) {
  ImageView imageView = ((MyViewHolder) viewHolder).imageView;
  String currentUrl = myUrls.get(position);

  GlideApp.with(fragment)
    .load(currentUrl)
    .override(imageWidthPixels, imageHeightPixels)
    .into(imageView);
}