Android recyclerview實現查看更多/收起功能

效果圖如下（沒搞GIF轉換工具，只能截圖了。。。）：

佈局文件activity_main.xml，就一個recyclerview:

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <android.support.v7.widget.RecyclerView
        android:id="@+id/rv_main"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"></android.support.v7.widget.RecyclerView>

</android.support.constraint.ConstraintLayout>

代碼MainActivity:

package seemore.test.com.seemorerecycleview;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.support.v7.widget.GridLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.widget.Toast;

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

public class MainActivity extends AppCompatActivity {

    private RecyclerView recyclerView;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        initView();
    }

    private void initView() {
        recyclerView = (RecyclerView) findViewById(R.id.rv_main);
        List<String> list = new ArrayList<>();
        for (int i = 0; i < 30; i++) {
            list.add("哈薩ki" + i);
        }
        SeeMoreAdapter seeMoreAdapter = new SeeMoreAdapter(list);
        recyclerView.setLayoutManager(new GridLayoutManager(this, 4));
        recyclerView.setAdapter(seeMoreAdapter);


        seeMoreAdapter.setOnITEMClickListener(new SeeMoreAdapter.OnItemClick() {
            @Override
            public void onItemClick(int position) {
                int mPosition = position + 1;
                Toast.makeText(getBaseContext(),"點擊了第"+ mPosition +"個哈薩ki",Toast.LENGTH_SHORT).show();
            }
        });
    }
}

佈局文件item_view:

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:padding="10dp"
    android:id="@+id/rl_item"
    >


    <ImageView
        android:id="@+id/iv_item"
        android:layout_width="40dp"
        android:layout_height="40dp"
        android:src="@mipmap/ic_launcher"/>

    <TextView
        android:id="@+id/itemView"
        android:text="name"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerHorizontal="true"
        android:layout_below="@+id/iv_item"/>

</RelativeLayout>

代碼SeeMoreAdapter：

package seemore.test.com.seemorerecycleview;

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.ImageView;
import android.widget.RelativeLayout;
import android.widget.TextView;

import java.util.List;

class SeeMoreAdapter extends RecyclerView.Adapter<SeeMoreAdapter.SeeMoreViewHolder> {

    private final static int TYPE_NORMAL = 0;//正常條目
    private final static int TYPE_SEE_MORE = 1;//查看更多
    private final static int TYPE_HIDE = 2;//收起
    private List<String> mList;
    private boolean mOpen = false;//是否是展開狀態

    SeeMoreAdapter(List<String> mList) {
        this.mList = mList;
    }

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

    @Override
    public void onBindViewHolder(@NonNull SeeMoreViewHolder seeMoreViewHolder, final int position) {
//        TextView textView = (TextView) seeMoreViewHolder.textView;
        if (getItemViewType(position) == TYPE_HIDE) {
            seeMoreViewHolder.textView.setText("收起");
            seeMoreViewHolder.rl_item.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    mOpen = false;
                    notifyDataSetChanged();
                }
            });
        } else if (getItemViewType(position) == TYPE_SEE_MORE) {
            seeMoreViewHolder.textView.setText("查看更多");
            seeMoreViewHolder.rl_item.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    mOpen = true;
                    notifyDataSetChanged();
                }
            });
        } else {
            seeMoreViewHolder.textView.setText(mList.get(position));
            seeMoreViewHolder.rl_item.setClickable(false);
            if (onItemClick!=null){
                seeMoreViewHolder.rl_item.setOnClickListener(new View.OnClickListener() {
                    @Override
                    public void onClick(View v) {
                        onItemClick.onItemClick(position);
                    }
                });
            }
        }
    }

    @Override
    public int getItemViewType(int position) {
        if (mList.size() <= 4) {
            return TYPE_NORMAL;
        }
        if (mOpen) {
            if (position == mList.size()) {
                return TYPE_HIDE;
            } else {
                return TYPE_NORMAL;
            }
        } else {
            if (position == 3) {
                return TYPE_SEE_MORE;
            } else {
                return TYPE_NORMAL;
            }
        }
    }

    @Override
    public int getItemCount() {
        if (mList == null || mList.size() == 0) {
            return 0;
        }
        if (mList.size() > 4) {
            //若現在是展開狀態 條目數量需要+1 "收起"條目
            if (mOpen) {
                return mList.size() + 1;
            } else {
                return 4;
            }
        } else {
            return mList.size();
        }
    }

    class SeeMoreViewHolder extends RecyclerView.ViewHolder {
        TextView textView ;
        ImageView iv_item ;
        RelativeLayout rl_item ;


        public SeeMoreViewHolder(@NonNull View itemView) {
            super(itemView);
            textView = itemView.findViewById(R.id.itemView);
            iv_item = itemView.findViewById(R.id.iv_item);
            rl_item = itemView.findViewById(R.id.rl_item);
        }
    }


    public interface OnItemClick{
        void onItemClick(int position);
    }
    private OnItemClick onItemClick;
    public void setOnITEMClickListener(OnItemClick onItemClick){
        this.onItemClick = onItemClick;
    }

}

代碼鏈接：https://download.csdn.net/download/qq_38306233/12311257