ImprovedRecyclerView

Based on the deprecated infinum MjolnirRecyclerView library, updated by using AndroidX and added more options: Parallax header and more is coming.

Prerequisites

Add this in your root build.gradle file (not your module build.gradle file):

allprojects {
    repositories {
        ...
        maven { url "https://jitpack.io" }
    }
}

Dependency

Add this to your module's build.gradle file (make sure the version matches the JitPack badge above):

dependencies {
    ...
    implementation 'com.github.invissvenska:ImprovedRecyclerView:VERSION'
}

Configuration

ImprovedRecyclerView provides methods to add header, footers, empty view and more in a simple way by extending the default RecyclerView behaviour.

Header & Footer

You can add optional header and footer to your list. These are optional so you don't have to set a header and/or footer.

adapter.setHeader(View view);
adapter.setFooter(View view);

Empty view

Empty view is supported. It will be shown automatically when the adapter is empty, and automatically hides when the adapter is populated.

recyclerView.setEmptyView(View view);

It is also possible to show the empty view while the adapter is not set. This is a handy when the adapter is initialized at a later point in time.

// show empty view when adapter is not set
recyclerView.setEmptyView(View view, true);

onClick

The onClick methods are already implemented for you by the library.

Implement the OnClickListener<E> interface in your Activity or Fragment and override the onClick method.

public class SimpleFragment extends Fragment implements SimpleAdapter.OnClickListener<String> {

    // some other code

   @Override
   public void onClick(int index, String item) {
       Toast.makeText(this.getContext(), item, Toast.LENGTH_SHORT).show();
   }
}

Paging

Paging can be used if you want to use less data in your app. Just add the initial set of items, and when you scroll down the next set of items will be added to the list.

Implement the OnNextPageListener interface in your Activity or Fragment and override the onScrolledToNextPage method.

public class NextPageFragment extends Fragment implements SimpleAdapter.OnNextPageListener {

    // some other code

    @Override
    public void onScrolledToNextPage() {
        // Fetch data and add it to the list, show some loading widget in UI to indicate loading
        adapter.addAll(ITEMS);
    }
}

Grid layout

Just use a GridLayoutManager instead of a LinearLayoutManager. Size of header and footer will be automatically spanned across the grid spansize.

...
recyclerView.setLayoutManager(new GridLayoutManager(getContext(), 3));

adapter = new SimpleAdapter(getContext());
recyclerView.setAdapter(adapter);

adapter.setHeader(R.layout.item_header);
adapter.setFooter(R.layout.item_footer);
...

DiffUtil

Only updates the different values in the RecyclerView and let the same values intact when giving a new list of items.

Extend the DiffUtil.Callback class and update the getChangePayload method according your needs. In this example only a string value is added to the Bundle.

public class ItemsDiffUtil extends DiffUtil.Callback {
    public static final String EXTRA_ITEM_DESCRIPTION = "EXTRA_ITEM_DESCRIPTION";

    private List<Item> oldList;
    private List<Item> newList;

    public ItemsDiffUtil(List<E> oldList, List<E> newList) {
        this.oldList = oldList;
        this.newList = newList;
    }

    @Nullable
    @Override
    public Object getChangePayload(int oldItemPosition, int newItemPosition) {
        Bundle bundle = new Bundle();
        bundle.putString(EXTRA_ITEM_DESCRIPTION, newList.get(newItemPosition).getName());
        return bundle;
    }

    @Override
    public int getOldListSize() {
        return oldList.size();
    }

    @Override
    public int getNewListSize() {
        return newList.size();
    }

    @Override
    public boolean areItemsTheSame(int oldItemPosition, int newItemPosition) {
        return oldList.get(oldItemPosition).getId() == newList.get(newItemPosition).getId();
    }

    @Override
    public boolean areContentsTheSame(int oldItemPosition, int newItemPosition) {
        return oldList.get(oldItemPosition).getName().equals(newList.get(newItemPosition).getName());
    }
}

In your Adapter add the following lines to in the onBind method to update only fill the updated items.

@Override
protected void bind(final Item item, final int position, List<Object> payloads) {
    if (payloads.isEmpty()) {
        tvPosition.setText(String.valueOf(item.getId()));
        tvText.setText(item.getName());
    } else {
        Bundle bundle = (Bundle) payloads.get(0);
        tvText.setText(bundle.getString(ItemsDiffUtil.EXTRA_ITEM_DESCRIPTION));
    }
    ...
}

In your Fragment or Activity call the update method in you Adapter to update only the different items:

adapter.update(newList, new ItemsDiffUtil(items, newList));

Parallax header

When you want to feel more depth in you app you can use the parallax option for the header.

Add the height of your header layout to your adapter, and add the ImprovedHeaderScrollListener to your RecyclerView.

LinearLayoutManager layoutManager = new LinearLayoutManager(getContext());
recyclerView.setLayoutManager(layoutManager);
recyclerView.setEmptyView(emptyView);

adapter = new SimpleAdapter(getContext(), (int) getResources().getDimension(R.dimen.parallax_height));
adapter.setHeader(R.layout.item_header);

recyclerView.setAdapter(adapter);
recyclerView.addOnScrollListener(new ResizeScrollListener<>(adapter, layoutManager));
adapter.addAll(ITEMS);

Screenshots

Please click the image below to enlarge.