1. 前言

RecyclerView 沒有提供類似ListView的setOnItemClickListener方法，所以只有我們自己為RecyclerView新增點選事件, 本篇文章主要介紹如何新增點選事件，進行Item增加和刪除，並且解決RecycleView Adapter使用notifyItemRemoved和notifyItemInserted造成Position混亂的問題。

2.新增點選事件

1）在Adapter中建立一個實現點選介面：

public interface OnItemClickLitener {
        void onItemClick(View view, int
 
 position);
    }

2）在Adapter中新增介面設定方法：

private OnItemClickLitener mOnItemClickListener = null;

    public void setOnItemClickListener(OnItemClickLitener listener) {
        this.mOnItemClickListener = listener;
    }

3）觸發itemClick回撥程式碼：

@Override
    public void onBindViewHolder(ViewHolder holder, int position) {
        holder.mTextView
 
.setText(data.get(position));
        holder.mTextView.setTag(holder.getLayoutPosition());
        holder.mTextView.setOnClickListener(this);
    }

@Override
    public void onClick(View v) {
        switch (v.getId()) {
            case R.id.item_text:
                mOnItemClickListener.onItemClick(v, (int
 
) v.getTag());
                break;
        }
    }

4）activity中註冊介面到Adapter中：

public class ItemClickListViewActivity extends AppCompatActivity {

    /**
     * view
     */
    private RecyclerView recyclerView;

    /**
     * 用來確定每一個item如何進行排列擺放，何時展示和隱藏
     */
    private LinearLayoutManager layoutManager;

    /**
     * 介面卡
     */
    private MyItemClickAdapter mAdapter;

    private ArrayList<String> data = new ArrayList<String>();

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        initView();
        initData();
    }

    /**
     * 初始化佈局元件
     */
    private void initView() {
        recyclerView = (RecyclerView) findViewById(R.id.recycler_view);
        //建立預設的線性LayoutManager
        layoutManager = new LinearLayoutManager(this);
//        layoutManager.setOrientation(LinearLayoutManager.HORIZONTAL);
        recyclerView.setLayoutManager(layoutManager);
        //如果可以確定每個item的高度是固定的，設定這個選項可以提高效能
        recyclerView.setHasFixedSize(true);
    }

    /**
     * 初始化資料
     */
    private void initData() {
        for (int i = 0; i < 100; i++) {
            data.add(i + "--->click");
        }
        //建立並設定Adapter
        mAdapter = new MyItemClickAdapter(data);
        recyclerView.setAdapter(mAdapter);
        recyclerView.setItemAnimator(new DefaultItemAnimator());
        mAdapter.setOnItemClickListener(new MyItemClickAdapter.OnItemClickLitener() {
            @Override
            public void onItemClick(View view, int position) {
                if(position ==2){
                    mAdapter.addItem("add click", 4);
                    Toast.makeText(ItemClickListViewActivity.this, "增加資料" + position, Toast.LENGTH_SHORT).show();
                }else if(position ==3) {
                    mAdapter.removeItem(2);
                    Toast.makeText(ItemClickListViewActivity.this, "刪除資料" + position, Toast.LENGTH_SHORT).show();
                }else{

                    Toast.makeText(ItemClickListViewActivity.this, "選中" + position, Toast.LENGTH_SHORT).show();
                }
            }
        });
    }
}

以上程式碼就可以為RecyclerView新增item點選事件了。

3.Item增加和刪除

在adpater中增加如下兩個方法：
1）新增資料：

public void addItem(String content, int position) {
        data.add(position, content);
        notifyItemInserted(position);
    }

2）刪除資料：

public void removeItem(int position) {
        data.remove(position);
        notifyItemRemoved(position);
    }

activity中呼叫上面兩個方法，實現增加跟刪除item

mAdapter.setOnItemClickListener(new MyItemClickAdapter.OnItemClickLitener() {
            @Override
            public void onItemClick(View view, int position) {
                if(position ==2){
                    mAdapter.addItem("add click", 4);
                    Toast.makeText(ItemClickListViewActivity.this, "增加資料" + position, Toast.LENGTH_SHORT).show();
                }else if(position ==3) {
                    mAdapter.removeItem(2);
                    Toast.makeText(ItemClickListViewActivity.this, "刪除資料" + position, Toast.LENGTH_SHORT).show();
                }else{

                    Toast.makeText(ItemClickListViewActivity.this, "選中" + position, Toast.LENGTH_SHORT).show();
                }
            }
        });

4.解決增加或者刪除position混亂的問題：

照Google文件描述在使用了notifyItemInserted時候原來位置的position會加1，但是事實證明資料的position位置毫無變化，暫且認為google工程師的錯誤吧，但是我們還是要繼續使用。一般有兩種解決辦法：
1）保留刪除跟新增動畫效果：notifyItemRemoved(position);notifyItemInserted(position);從原始碼可以看出，他只是重新整理當前插入或者刪除的item，不會觸發onBindViewHolder，所以插入或者刪除的item的下方的item的postion會有混亂。所以我們手動來重新整理，程式碼如下：

public void removeItem(int position) {
        data.remove(position);
        notifyItemRemoved(position);
        // 加入如下程式碼保證position的位置正確性
        if (position != data.size() - 1) {
            notifyItemRangeChanged(position, data.size() - position);
        }
    }

    public void addItem(String content, int position) {
        data.add(position, content);
        notifyItemInserted(position);
        // 加入如下程式碼保證position的位置正確性
        if (position != data.size() - 1) {
            notifyItemRangeChanged(position, data.size() - position);
        }
    }

2）去掉動畫：直接使用notifyDataSetChanged();因為使用notifyDataSetChanged();後，動畫則消失了。

public void removeItem(int position) {
        data.remove(position);
        notifyItemRemoved(position);
        notifyDataSetChanged();
    }

    public void addItem(String content, int position) {
        data.add(position, content);
        notifyItemInserted(position);
        notifyDataSetChanged();
    }

5.完整程式碼

activity程式碼：

package com.test.recyclerview.itemclick;

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.DefaultItemAnimator;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.view.View;
import android.widget.Toast;

import com.test.recyclerview.R;

import java.util.ArrayList;

public class ItemClickListViewActivity extends AppCompatActivity {

    /**
     * view
     */
    private RecyclerView recyclerView;

    /**
     * 用來確定每一個item如何進行排列擺放，何時展示和隱藏
     */
    private LinearLayoutManager layoutManager;

    /**
     * 介面卡
     */
    private MyItemClickAdapter mAdapter;

    private ArrayList<String> data = new ArrayList<String>();

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        initView();
        initData();
    }

    /**
     * 初始化佈局元件
     */
    private void initView() {
        recyclerView = (RecyclerView) findViewById(R.id.recycler_view);
        //建立預設的線性LayoutManager
        layoutManager = new LinearLayoutManager(this);
//        layoutManager.setOrientation(LinearLayoutManager.HORIZONTAL);
        recyclerView.setLayoutManager(layoutManager);
        //如果可以確定每個item的高度是固定的，設定這個選項可以提高效能
        recyclerView.setHasFixedSize(true);
    }

    /**
     * 初始化資料
     */
    private void initData() {
        for (int i = 0; i < 100; i++) {
            data.add(i + "--->click");
        }
        //建立並設定Adapter
        mAdapter = new MyItemClickAdapter(data);
        recyclerView.setAdapter(mAdapter);
        recyclerView.setItemAnimator(new DefaultItemAnimator());
        mAdapter.setOnItemClickListener(new MyItemClickAdapter.OnItemClickLitener() {
            @Override
            public void onItemClick(View view, int position) {
                if(position ==2){
                    mAdapter.addItem("add click", 4);
                    Toast.makeText(ItemClickListViewActivity.this, "增加資料" + position, Toast.LENGTH_SHORT).show();
                }else if(position ==3) {
                    mAdapter.removeItem(2);
                    Toast.makeText(ItemClickListViewActivity.this, "刪除資料" + position, Toast.LENGTH_SHORT).show();
                }else{

                    Toast.makeText(ItemClickListViewActivity.this, "選中" + position, Toast.LENGTH_SHORT).show();
                }
            }
        });
    }
}

adapter程式碼：

package com.test.recyclerview.itemclick;

import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;

import com.test.recyclerview.R;

import java.util.ArrayList;


public class MyItemClickAdapter extends RecyclerView.Adapter<MyItemClickAdapter.ViewHolder> implements View.OnClickListener {
    private OnItemClickLitener mOnItemClickListener = null;

    public void setOnItemClickListener(OnItemClickLitener listener) {
        this.mOnItemClickListener = listener;
    }

    private ArrayList<String> data;

    public MyItemClickAdapter(ArrayList<String> data) {
        this.data = data;
    }

    @Override
    public ViewHolder onCreateViewHolder(ViewGroup viewGroup, int viewType) {
        View view = LayoutInflater.from(viewGroup.getContext()).inflate(R.layout.activity_item, viewGroup, false);
        return new ViewHolder(view);
    }

    @Override
    public void onBindViewHolder(ViewHolder holder, int position) {
        holder.mTextView.setText(data.get(position));
        holder.mTextView.setTag(holder.getLayoutPosition());
        holder.mTextView.setOnClickListener(this);
    }

    @Override
    public int getItemCount() {
        return data == null ? 0 : data.size();
    }

    @Override
    public void onClick(View v) {
        switch (v.getId()) {
            case R.id.item_text:
                mOnItemClickListener.onItemClick(v, (int) v.getTag());
                break;
        }
    }

    //自定義的ViewHolder，持有每個Item的的所有介面元素
    public static class ViewHolder extends RecyclerView.ViewHolder {
        public TextView mTextView;

        public ViewHolder(View view) {
            super(view);
            mTextView = (TextView) view.findViewById(R.id.item_text);
        }
    }

    public void removeItem(int position) {
        data.remove(position);
        notifyItemRemoved(position);
        // 加入如下程式碼保證position的位置正確性
        if (position != data.size() - 1) {
            notifyItemRangeChanged(position, data.size() - position);
        }
    }

    public void addItem(String content, int position) {
        data.add(position, content);
        notifyItemInserted(position);
        // 加入如下程式碼保證position的位置正確性
        if (position != data.size() - 1) {
            notifyItemRangeChanged(position, data.size() - position);
        }
    }

    public interface OnItemClickLitener {
        void onItemClick(View view, int position);
    }
}

6.完整程式碼下載地址如下所示：

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