A Simple Generic Implementation of `RecyclerView.Adapter`.

SimpleRecyclerViewAdapter.java

import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

import androidx.annotation.LayoutRes;
import androidx.annotation.NonNull;
import androidx.core.util.Supplier;
import androidx.recyclerview.widget.RecyclerView;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

public class SimpleRecyclerViewAdapter<T> extends RecyclerView.Adapter<SimpleRecyclerViewAdapter.ViewHolder> {
    private final int resource;
    private int itemCount = 0;
    private List<T> items;

    private OnBindViewHolderListener onBindViewHolderListener;
    private OnCreateViewHolderListener onCreateViewHolderListener;

    public SimpleRecyclerViewAdapter(@LayoutRes final int resource) {
        this(resource, new ArrayList<>(0));
    }

    public SimpleRecyclerViewAdapter(@LayoutRes final int resource, List<T> items) {
        this.resource = resource;
        this.setItems(items);
    }

    @NonNull
    @Override
    public SimpleRecyclerViewAdapter.ViewHolder onCreateViewHolder(@NonNull ViewGroup viewGroup, int i) {
        View layoutView = LayoutInflater.from(viewGroup.getContext()).inflate(resource, viewGroup, false);
        return this.onCreateViewHolderListener == null ? new SimpleRecyclerViewAdapter.ViewHolder(layoutView) : new SimpleRecyclerViewAdapter.ViewHolder(layoutView, onCreateViewHolderListener);
    }

    @Override
    public void onBindViewHolder(@NonNull SimpleRecyclerViewAdapter.ViewHolder viewHolder, int i) {
        if (onBindViewHolderListener != null) {
            onBindViewHolderListener.onBind(viewHolder, i);
        }
    }

    public void setItemCount(int count){
        this.itemCount=count;
        notifyDataSetChanged();
    }

    @Override
    public int getItemCount() {
        if (itemCount > items.size())
            return itemCount;
        return items.size();
    }

    public void setItem(int pos, T item) {
        this.getItems().set(pos, item);
        notifyItemChanged(pos);
    }

    public void setItems(List<T> items) {
        this.items = items;
        notifyDataSetChanged();
    }

    public void setItems(T[] items) {
        this.items = Arrays.asList(items);
        notifyDataSetChanged();
    }

    public void addItem(int pos, T item) {
        this.items.add(pos, item);
        notifyItemInserted(pos);
    }

    public void removeItem(int pos) {
        this.items.remove(pos);
        notifyItemRemoved(pos);
    }

    public List<T> getItems() {
        return this.items;
    }


    public SimpleRecyclerViewAdapter<T> setOnBindViewHolderListener(OnBindViewHolderListener onBindViewHolderListener) {
        this.onBindViewHolderListener = onBindViewHolderListener;
        return this;
    }

    public OnCreateViewHolderListener getOnCreateViewHolderListener() {
        return onCreateViewHolderListener;
    }

    public void setOnCreateViewHolderListener(OnCreateViewHolderListener onCreateViewHolderListener) {
        this.onCreateViewHolderListener = onCreateViewHolderListener;
    }

    public OnBindViewHolderListener getOnBindViewHolderListener() {
        return onBindViewHolderListener;
    }

    public static class ViewHolder extends RecyclerView.ViewHolder {
        ViewHolder(@NonNull View itemView) {
            super(itemView);
        }

        ViewHolder(@NonNull View itemView, OnCreateViewHolderListener listener) {
            super(itemView);
            listener.onCreate(this, this::getAdapterPosition);
        }

    }

    public interface OnCreateViewHolderListener {
        void onCreate(SimpleRecyclerViewAdapter.ViewHolder viewHolder, Supplier<Integer> supplier);
    }

    public interface OnBindViewHolderListener {
        void onBind(SimpleRecyclerViewAdapter.ViewHolder viewHolder, int pos);
    }


}