Android-BaseAdapter-recyclerView.java

public abstract class BaseAdapter<D> extends RecyclerView.Adapter<BaseViewHolder> {

    public static final int VIEW_TYPE_ITEM = 1;
    public static final int VIEW_TYPE_FOOTER = 2;

    protected ArrayList<D> dataList;
    protected Context context;
    protected LayoutInflater layoutInflater;

    private BaseAdapter(){}

    public BaseAdapter(Context context){
        this.context = context;
        dataList = new ArrayList<>();
        layoutInflater = LayoutInflater.from(context);
    }


    @Override
    public int getItemViewType(int position) {
        return dataList.get(position) == null ? VIEW_TYPE_FOOTER : VIEW_TYPE_ITEM;
    }

    public void add(D singleData){
        dataList.add(singleData);
        notifyItemInserted(dataList.size() -1);
    }

    public void addAll(ArrayList<D> dataList){
        for(D singleData: dataList){
            add(singleData);
        }
    }

    public D getItem(int position) {
        return dataList.get(position);
    }

    public void addLoadingFooter() {
        dataList.add(null);
        notifyItemInserted(dataList.size() - 1);
    }

    public void removeLoadingFooter() {
        dataList.remove(dataList.size() - 1);
        notifyItemRemoved(dataList.size());
    }

    public void remove(D singleData) {
        int position = dataList.indexOf(singleData);
        if (position > -1) {
            dataList.remove(position);
            notifyItemRemoved(position);
        }
    }

    public void remove(int position){
        if(!dataList.isEmpty()){
            dataList.remove(position);
            notifyItemRemoved(position);
        }
    }

    public void clear() {
        while (getItemCount() > 0) {
            remove(getItem(0));
        }
    }

    @Override
    public int getItemCount() {
        return dataList.isEmpty() ? 0 : dataList.size();
    }


    static class FooterViewHolder extends BaseViewHolder{

        FooterViewHolder(@NonNull ViewDataBinding viewDataBinding) {
            super(viewDataBinding);
        }

        @Override
        public void bind(int position) {

        }
    }


    public BaseViewHolder getFooterViewHolder(@NonNull ViewGroup viewGroup){
        return  new FooterViewHolder(DataBindingUtil.inflate(layoutInflater,
                R.layout.looding_footer,
                viewGroup,
                false));
    }

}


////// Base View Holder..........................
public abstract class BaseViewHolder extends RecyclerView.ViewHolder {

    private final ViewDataBinding viewDataBinding;

    protected BaseViewHolder(@NonNull ViewDataBinding viewDataBinding) {
        super(viewDataBinding.getRoot());
        this.viewDataBinding = viewDataBinding;
    }

    public abstract void bind(int position);

    protected ViewDataBinding getViewBinding(){ return viewDataBinding;}

}


// Usage of this Base Adapter In Adapter Class.....................
public class MyAdapter extends BaseAdapter<String>{

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

    @NonNull
    @Override
    public BaseViewHolder onCreateViewHolder(@NonNull ViewGroup viewGroup, int viewType) {
        if(viewType == BaseAdapter.VIEW_TYPE_FOOTER){
            return super.getFooterViewHolder(viewGroup);
        }else{
            return new ItemViewHolder(DataBindingUtil.inflate(layoutInflater,
                    R.layout.item_view,
                    viewGroup,
                    false));
        }
    }

    @Override
    public void onBindViewHolder(@NonNull BaseViewHolder viewHolder, int position) {
        if(viewHolder instanceof ItemViewHolder){
            viewHolder.bind(position);
        }
    }


    public class ItemViewHolder extends BaseViewHolder{

        ItemViewHolder(@NonNull ViewDataBinding viewDataBinding) {
            super(viewDataBinding);
        }

        @Override
        public void bind(int position) {
            if(dataList.get(position) != null){
                getViewBinding().setVariable(BR.item, dataList.get(position));
                getViewBinding().executePendingBindings();
            }
        }
    }
}