FirebaseRecyclerAdapter doesn't recognize first layout as a position

Question

My Title is kind of hard to understand but basically when I add items into my database is should display it in a RecyclerView. Now in my RecyclerView I have two

Answer 1

Why use the Firebase Recycler Adapter when you could easily make a custom one? If I understood well you want an item to be fixed at position 0 (header) while others will be added below the first one, right? If so, here is a solution I like to use:

public interface ViewType {
    public int getViewType();
}

public interface ViewTypeDelegateAdapter {
    public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent);
    public void onBindViewHolder(RecyclerView.ViewHolder holder, ViewType item);
}

public class ViewTypes {
    public static int HEADER = 0
    public static int ITEM = 1
}

public class ProductDelegateAdapter implements ViewTypeDelegateAdapter {

    private int resID;
    private Context context;

    public ProductDelegateAdapter(int resID, Context context) {
        this.resID = resID;
        this.context = context;
    }

    public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent) {
        return new ProductHolder(LayoutInflater.from(parent.context).inflate(resID, parent, false));
    }

    @Override
    public void onBindViewHolder(RecyclerView.ViewHolder holder, ViewType item) {
        (holder as ProductHolder).bind("test");
    }

    class ProductHolder extends RecyclerView.ViewHolder {

        public ProductHolder(View view) {
            super(view);
        }

        public void bind(String test) {

        }

    }

}

public class HeaderDelegateAdapter implements ViewTypeDelegateAdapter {

    private int resID;
    private Context context;

    public ProductDelegateAdapter(int resID, Context context) {
        this.resID = resID;
        this.context = context;
    }

    public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent) {
        return new HeaderHolder(LayoutInflater.from(parent.context).inflate(resID, parent, false));
    }

    @Override
    public void onBindViewHolder(RecyclerView.ViewHolder holder, ViewType item) {
        (holder as HeaderHolder).bind("test");
    }

    class HeaderHolder extends RecyclerView.ViewHolder {

        public HeaderHolder(View view) {
            super(view);
        }

        public void bind(String test) {

        }

    }

}

public class AccAdapter extends RecyclerView.Adapter() {

    private Context context;
    private List items;
    private SparseArrayCompat delegateAdapters;
    private ViewType headerItem;

    public AccAdapter(Context context) {
        this.context = context;
        this.items = new ArrayList();
        this.delegateAdapters = new SparseArrayCompat();
        this.headerItem = new ViewType() {
            @Override
            public int getViewType() {
                return ViewTypes.HEADER;
            }
        };

        this.items.add(this.headerItem);
        this.delegateAdapters.put(ViewTypes.HEADER, HeaderDelegateAdapter(R.id.test, this.context));
        this.delegateAdapters.put(ViewTypes.ITEM, ProductDelegateAdapter(R.id.test, this.context));
    }

    @Override
    public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, Int viewType) {
        return delegateAdapters.get(viewType).onCreateViewHolder(parent);
    }

    @Override
    public void onBindViewHolder(RecyclerView.ViewHolder holder, Int position) {
        delegateAdapters.get(getItemViewType(position)).onBindViewHolder(holder, items[position])
    }

    @Override
    public Int getItemViewType(Int position) {
        return items.get(position).getViewType();
    }

    @Override
    public Int getItemCount() {
        return items.getSize();
    }

    public void add(ViewType viewType) {
        val initPosition = this.items.size - 1
        this.items.add(item)
        notifyItemRangeChanged(initPosition, this.items.size + 1)
    }

}

public class Event implements ViewType {

    private String id;

    @Override
    public int getViewType() {
        return ViewTypes.ITEM;
    }

}

Excuse me for some syntax errors, I've translated to Java from Kotlin to help you. Hope it helps!