thmodelAndroid/app/src/main/java/com/android/chmo/ui/adpater/BaseAdapter.java

package com.android.chmo.ui.adpater;

import android.support.annotation.NonNull;
import android.support.v7.widget.RecyclerView;
import android.view.View;
import android.view.ViewGroup;

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

public abstract class BaseAdapter<VH extends RecyclerView.ViewHolder> extends RecyclerView.Adapter {
    private List<View> headerViews;
    private List<View> footerViews;

    public BaseAdapter() {
        headerViews = new ArrayList<>();
        footerViews = new ArrayList<>();
    }

    public void addHeaderView(View view) {
        headerViews.add(view);
    }

    @NonNull
    @Override
    public RecyclerView.ViewHolder onCreateViewHolder(@NonNull ViewGroup viewGroup, int i) {
        if (i < headerViews.size()) {
            return new HeaderFooterHolder(headerViews.get(i));
        } else if (i < (headerViews.size() + getDataCount())) {
            return getViewHolder(viewGroup, i - headerViews.size());
        } else {
            return new HeaderFooterHolder(footerViews.get(i - headerViews.size() - getDataCount()));
        }
    }

    @Override
    public void onBindViewHolder(@NonNull RecyclerView.ViewHolder viewHolder, int i) {
        if (i >= headerViews.size() && i < (headerViews.size() + getDataCount())) {
            updateViewHolder((VH) viewHolder, i - headerViews.size());
        }
    }

    @Override
    public int getItemCount() {
        return getDataCount() + headerViews.size() + footerViews.size();
    }

    @Override
    public int getItemViewType(int position) {
        return position;
    }

    protected abstract int getDataCount();

    protected abstract VH getViewHolder(@NonNull ViewGroup viewGroup, int position);

    protected abstract void updateViewHolder(@NonNull VH holder, int position);

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