RecyclerView doesn't have an emptyView support, we gotta fix that

EmptyRecyclerView.java

import android.content.Context;
import android.support.v7.widget.RecyclerView;
import android.util.AttributeSet;
import android.view.View;
import org.jetbrains.annotations.NotNull;
import org.jetbrains.annotations.Nullable;

public class EmptyRecyclerView extends RecyclerView {
  @Nullable View emptyView;

  public EmptyRecyclerView(Context context) { super(context); }

  public EmptyRecyclerView(Context context, AttributeSet attrs) { super(context, attrs); }

  public EmptyRecyclerView(Context context, AttributeSet attrs, int defStyle) {
    super(context, attrs, defStyle);
  }

  void checkIfEmpty() {
    if (emptyView != null) {
      emptyView.setVisibility(getAdapter().getItemCount() > 0 ? GONE : VISIBLE);
    }
  }

  final @NotNull AdapterDataObserver observer = new AdapterDataObserver() {
    @Override public void onChanged() {
      super.onChanged();
      checkIfEmpty();
    }
  };

  @Override public void setAdapter(@Nullable Adapter adapter) {
    final Adapter oldAdapter = getAdapter();
    if (oldAdapter != null) {
      oldAdapter.unregisterAdapterDataObserver(observer);
    }
    super.setAdapter(adapter);
    if (adapter != null) {
      adapter.registerAdapterDataObserver(observer);
    }
  }

  public void setEmptyView(@Nullable View emptyView) {
    this.emptyView = emptyView;
    checkIfEmpty();
  }
}

Consider adding onItemRangeInserted and onItemRangeInserted to the observer

onChange is not fired when notifyItemRangeInserted and notifyItemRangeInserted is called on the adapter.

onItemRangeInserted, called when notifyItemRangeInserted).
Scenario: Initially the list is empty. But after adding items in range it will not be empty

onItemRangeRemoved to, called when notifyItemRangeRemoved is used.
Scenario: All the items might be removed from the data set and it may be empty

Thanks for the gist. I have forked you gist and added the above the changes. Also I have used Android's annotation instead of JetBrains to support Android Studio

Hi, you are a popular man!

Hello, I would like to use this code in future projects of mine.

• Are you the original author?

Would you be happy if I fork this and add an Apache v2 licence to my copy, with attribution to you?

Thanks,
Richard
Glowworm Software
Cape Town, South Africa

@mobiRic you can do whatever you want with this code :)

Thanks - forked to https://gist.github.com/mobiRic/963a814d51259c730467

Can I suggest adding a method for swapAdapter() for completeness:

@Override
public void swapAdapter(Adapter adapter, boolean removeAndRecycleExistingViews) {
    final Adapter oldAdapter = getAdapter();
    if (oldAdapter != null) {
        oldAdapter.unregisterAdapterDataObserver(observer);
    }

    if (adapter != null) {
        adapter.registerAdapterDataObserver(observer);
    }
    super.swapAdapter(adapter, removeAndRecycleExistingViews);
    checkIfEmpty();
}

@AnirudhaAgashe suggestion is correct!

@notnul coudnl't resolve

maybe the emptyView attribute could be private

Hi @adelnizamutdinov , This we can achieve in flowing way.
Make two list item one for showing normal data and another one is for empty view

1. In getitemcount, if count is zero return 1 otherwise size of an adapter.
2. In itemViewType if size 0 return empty view type otherwise return your normal list item.

Really appreciate this great idea . It works well.

adapter.notifyItemRemoved(position); will not evoke checkIfEmpty()

But where is the emptyView attached?

Does nothing when I use following method :
recyclerView.postDelayed(() -> Notify RecyclerView

Inflated like this :
View headerView = View.inflate(getActivity(), R.layout.layout_empty_view, null);

@adelnizamutdinov
Hi, I think there's a small typo on line 25. Shouldn't it be @NonNull instead of @NotNull?

It is also not working without implementing onItemRangeInserted in the observer. I'm using FirebaseUI.

I have the same question, where is the emptyView attached?

Its good but what happened if we had to add one more observer to for lazy loading/paging?