How to redraw parent Fragment of RecyclerView when its content changes

Question

I've built a very simple online shop. I navigate through the app by using a BottomNavigationView (There is one Activity containing the navBar and multiple Fragments which are opened from this bar). In the Fragment for the shoppingcart I give the opportunity to remove items from the cart.

Then following problems occurs:

• I remove the item but only the RecyclerView gets updated, not the whole Fragment.
• This is an issue since the Fragment's Layout is dependent on the content of the RecyclerView (if recyclerView is empty → hide whole layout, etc.)

So here is my onBindViewHolder for the RecyclerView:

CartAdapter:

@Override
    public void onBindViewHolder(ViewHolder holder, final int position) {
        final int pos = position;

        Item item = CartViewModel.getInstance().mShoppingCartItems.get(position);

        vh.nameTextView.setText(item.getmTitle());
        vh.quantityTextView.setText(String.valueOf("Anzahl: " + item.getmQuantity()));
        vh.priceTextView.setText("€ " + item.getmPrice());
        vh.nameTextView.setAllCaps(true);
        vh.deleteButton.setBackground(null);

        Picasso.with(mContext).load(item.getmPictureLink()).into(vh.pictureImageView);

        holder.deleteButton.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {
                Item theRemovedItem = CartViewModel.getInstance().mShoppingCartItems.get(pos);
                CartViewModel.getInstance().mShoppingCartItems.remove(pos);
                notifyItemRemoved(pos);
                //force the parent Fragment to update it's layout
            }
        });
    }

Basically my question is: How can i update the layout of the fragment from my CartAdapter? Is there any other way to accomplish the desired behavior?

Answer 1

If somebody else comes across this: i finally resolved the issue with an interface :

public interface CartCallback {
    void onMethodCallback();
}

CartAdapter:

public class CartAdapter extends RecyclerView.Adapter < CartAdapter.ViewHolder > {

    private CartCallback mAdapterCallback;

    CartAdapter(CartCallback callback) {
        this.mAdapterCallback = callback;
    }

    public void onBindViewHolder(ViewHolder holder, @SuppressLint("RecyclerView") final int position) {

        // ....

        holder.deleteButton.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {
                CartViewModel.getInstance().mShoppingCartItems.remove(position);
                notifyItemRemoved(position);
                mAdapterCallback.onMethodCallback();
            }
        });
    }
}

CartFragment:

public class CartFragment extends Fragment implements CartCallback {

    @Override
    public void onCreate(Bundle savedInstanceState) {
        this.adapter = new CartAdapter(this);
    }

    @Override
    public void onMethodCallback() {
        Fragment frg = getActivity().getSupportFragmentManager().findFragmentByTag("CartFragment");
        final FragmentTransaction ft = getActivity().getSupportFragmentManager().beginTransaction();
        ft.detach(frg);
        ft.attach(frg);
        ft.commit();
    }

}