RecyclerView review

Universal Adapter

Code

package com.example.day15_lesson.Lesson;

import android.content.Context;
import android.support.annotation.NonNull;
import android.support.v7.widget.RecyclerView;
import android.util.SparseArray;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

import java.util.ArrayList;

public abstract class MyAdapter<T> extends RecyclerView.Adapter<BaseHolder> {

    int layoutId;
    ArrayList<T> list = new ArrayList<>();

    public MyAdapter(int layoutId) {
        this.layoutId = layoutId;
    }
    public void refresh(ArrayList<T>list ){
        this.list.addAll(list);
        notifyDataSetChanged();
    }

    public abstract void bind(BaseHolder holder, int i);

    @NonNull
    @Override
    public BaseHolder onCreateViewHolder(@NonNull ViewGroup viewGroup, int i) {
        View view = LayoutInflater.from(viewGroup.getContext()).inflate(layoutId, viewGroup, false);
        return new BaseHolder(view);
    }

    @Override
    public void onBindViewHolder(@NonNull BaseHolder baseHolder, int i) {

        bind(baseHolder, i);
    }

    @Override
    public int getItemCount() {
        return list.size();
    }
}

## head termination code

package com.example.day15.lesson;

import android.content.Context;
import android.support.annotation.NonNull;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
import android.widget.Toast;

import com.example.day15.R;

import java.util.List;

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

    private final LayoutInflater mLayoutInflater;
    private Context mContext;
    private List<String> mData;

    private final static int ITEM_HEADER=0;
    private final static int ITEM_CONTENT=1;
    private final static int ITEM_FOOT=2;

    /**
     * 头布局和尾布局的数量
     */
    private int mHeader=1;
    private int mFoot=1;

    public RvHFAdapter(Context context, List<String> data) {
        mContext = context;
        mData = data;
        mLayoutInflater = LayoutInflater.from(context);
    }

    @NonNull
    @Override
    public RecyclerView.ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        if (viewType==ITEM_CONTENT){
            View view = mLayoutInflater.inflate(R.layout.item_rv_linear, parent, false);
            return new ViewHolder(view);
        }
        if (viewType==ITEM_HEADER){
            View view = mLayoutInflater.inflate(R.layout.header_rv_linear, parent, false);
            return new HeaderViewHolder(view);
        }
        if (viewType==ITEM_FOOT){
            View view = mLayoutInflater.inflate(R.layout.footer_rv_linear, parent, false);
            return new FooterViewHolder(view);
        }
        return null;
    }

    @Override
    public void onBindViewHolder(@NonNull RecyclerView.ViewHolder holder, int position) {
        //Log.e("MMM", "onBindViewHolder: "+position);

        if (holder instanceof ViewHolder){
            ((ViewHolder) holder).tvText.setText(mData.get(position-mHeader));
        }
    }

    @Override
    public int getItemCount() {
        //固定数目,一个头,一个尾
        return mData.size()+mHeader+mFoot;
    }


    @Override
    public int getItemViewType(int position) {
        if (mHeader!=0&&position<mHeader){
            return ITEM_HEADER;
        }
        if (mFoot!=0&&position>=mData.size()+mHeader){
            return ITEM_FOOT;
        }
        return ITEM_CONTENT;
    }

    class ViewHolder extends RecyclerView.ViewHolder {
        TextView tvText;
        public ViewHolder(View itemView) {
            super(itemView);
            tvText=itemView.findViewById(R.id.show);
        }
    }
    class HeaderViewHolder extends RecyclerView.ViewHolder {
        public HeaderViewHolder(View itemView) {
            super(itemView);
        }
    }
    class FooterViewHolder extends RecyclerView.ViewHolder {
        public FooterViewHolder(View itemView) {
            super(itemView);
        }
    }
}

```