詳解Android RecyclerView

目錄

• 點擊事件
• 添加、刪除數據
• 更豐富的條目展示(多條目展示)
• 添加header 、footer
• 下拉刷新、上拉加載更多

進階一：點擊事件、長按事件(實現adapter和Activity之間的通信)

RecyclerView要實現點擊事件和長按事件可以在適配器中定義接口事件回調

1、定義對象
private OnItemClickListener mOnItemClickListener;
2、寫接口，並定義方法
/**
* 通過在adapter定義接口實現回調
*/
public interface OnItemClickListener {
   //點擊事件
   void onItemClick(View view, int position);

   //長按點擊事件
   void onItemLongClick(View view, int position);
}
3、
public void setOnItemClickListener(OnItemClickListener mOnItemClickListener) {
        this.mOnItemClickListener = mOnItemClickListener;
}
4、在adapter需要的地方調用事件
if (mOnItemClickListener != null) {
   mOnItemClickListener.onItemClick(((ContentViewHolder) holder).llLayout, position - 1);
}
if (mOnItemClickListener != null) {
   mOnItemClickListener.onItemLongClick(((ContentViewHolder) holder).llLayout, position - 1);
}
5、Activity調用Adapter中的事件
recyclerViewAdapter.setOnItemClickListener(new RecyclerViewAdapter.OnItemClickListener() {
            @Override
            public void onItemClick(View view, int position) {
                Toast.makeText(RecycleActivity.this, "點擊了第" + position + "條", Toast.LENGTH_SHORT).show();
            }

            @Override
            public void onItemLongClick(View view, int position) {
                Toast.makeText(RecycleActivity.this, "長按了第" + position + "條", Toast.LENGTH_SHORT).show();
            }
});

進階二：添加數據、刪除某條數據

這裏需要瞭解到刷新界面的多種方式

        notifyDataSetChanged();//刷新整體佈局
        notifyItemChanged(position);//刷新指定position,會重新調用onBindViewHolder來進行刷新，如果當前position在屏幕之外，則不會調用，當重新滾動到屏幕內，會重新調用
        notifyItemRangeChanged(position, 10);//刷新從position開始之後10條數據
        notifyItemInserted(position);//在第position處插入數據，這個插入時會有動畫
        notifyItemMoved(position,5);//將當前position移動到position爲5的地方，並且刷新
        notifyItemRangeInserted(3,10);//批量增加
        notifyItemRemoved(position);//刪除第position條數據
        notifyItemRangeRemoved(position, 10);//批量刪除

/**
     * 刪除某條數據
     *
     * @param position
     */
    public void removeData(int position) {
        mList.remove(position);
        notifyItemRemoved(position);
        notifyItemRangeChanged(position, mList.size());

    }
        /**
         * 在指定position添加數據
         *
         * @param position
         */
        public void addData(int position, String msg) {
            if (mList == null) {
                mList = new ArrayList<>();
            }
            if (position < mList.size()) {
                //說明這裏是第一條
                mList.add(position, msg);
            } else {
                mList.add(msg);
                position = mList.size() - 1;
            }
            notifyItemInserted(position);
            notifyItemRangeChanged(position, mList.size());
        }

問題一：長按事件、點擊事件同時發生

[外鏈圖片轉存失敗,源站可能有防盜鏈機制,建議將圖片保存下來直接上傳(img-F5gkIlym-1580817649921)(//upload-images.jianshu.io/upload_images/15649819-5d960683419a4173.gif?imageMogr2/auto-orient/strip|imageView2/2/w/360/format/webp)]

解決思路

在public boolean onLongClick(View v) {return true}
需要消費掉這個長按事件 返回true

[外鏈圖片轉存失敗,源站可能有防盜鏈機制,建議將圖片保存下來直接上傳(img-OMX7x7VO-1580817649922)(//upload-images.jianshu.io/upload_images/15649819-c63ab1c56a29a8c6.gif?imageMogr2/auto-orient/strip|imageView2/2/w/360/format/webp)]

進階三：添加header、footer

思路

1、首先要區分頭佈局、中間佈局、尾佈局三種不同的type，通過設置一個int值來判斷不同的佈局
2、通過getItemViewType來返回type
3、在onCreateViewHolder中根據不同的viewType顯示不同的佈局
4、在onBindViewHolder根據不同的holder加載不同的數據

注意

1、getItemCount這裏需要返回的集合的數量+header數量+footer數量
2、當content佈局中加載數據是通過position獲取數據時需要將
position-1

1、添加三種不同的type來區分不同的佈局

public static final int ITEM_TYPE_CONTENT = 0;
public static final int ITEM_TYPE_FOOTER = 1;
public static final int ITEM_TYPE_HEADER = 2;

2、添加頭、尾佈局數量

private int footerCount = 1;
private int headerCount = 1;

3、根據position獲取Item的類型

@Override
    public int getItemViewType(int position) {
        if (isHeaderView(position)) {
            return ITEM_TYPE_HEADER;
        } else if (isFooterView(position)) {
            return ITEM_TYPE_FOOTER;
        } else {
            return ITEM_TYPE_CONTENT;
        }
    }

4、根據不同的viewType顯示不同的佈局

 @NonNull
        @Override
        public RecyclerView.ViewHolder onCreateViewHolder(@NonNull ViewGroup viewGroup, int viewType) {
            /**
             * 主要負責把加載子項的佈局
             * 將xml定義的佈局實例化爲view對象
             */
            if (viewType == ITEM_TYPE_FOOTER) {
                View view = LayoutInflater.from(mContext).inflate(R.layout.recycler_footer_item, viewGroup, false);
                return new FooterViewHolder(view);
            } else if (viewType == ITEM_TYPE_HEADER) {
                View view = LayoutInflater.from(mContext).inflate(R.layout.recycler_header_item, viewGroup, false);
                return new HeaderViewHolder(view);
            } else if (viewType == ITEM_TYPE_CONTENT) {
                View view = LayoutInflater.from(mContext).inflate(R.layout.recyclerview_item, viewGroup, false);
                return new ContentViewHolder(view);
            }
            return null;
        }

5、根據不同的ViewHolder加載不同的數據(注意content中通過position加載數據position需要-1)

 @Override
            public void onBindViewHolder(@NonNull RecyclerView.ViewHolder holder, int position) {
                //主要負責綁定數據
                if (holder instanceof HeaderViewHolder) {

                } else if (holder instanceof FooterViewHolder) {

                } else if (holder instanceof ContentViewHolder) {
                    ((ContentViewHolder) holder).tvItem.setText(mList.get(position - 1));
                    ((ContentViewHolder) holder).llLayout.setOnClickListener(new View.OnClickListener() {
                        @Override
                        public void onClick(View v) {
                            if (mOnItemClickListener != null) {
                                mOnItemClickListener.onItemClick(((ContentViewHolder) holder).llLayout, position - 1);
                            }
                        }
                    });
                    ((ContentViewHolder) holder).llLayout.setOnLongClickListener(new View.OnLongClickListener() {
                        @Override
                        public boolean onLongClick(View v) {
                            if (mOnItemClickListener != null) {
                                mOnItemClickListener.onItemLongClick(((ContentViewHolder) holder).llLayout, position - 1);
                            }
                            return true;
                        }
                    });
                }

            }

6、返回的集合數量(務必加上header、footer)

@Override
                public int getItemCount() {
                    //返回集合的數量
                    return mList.size() + headerCount + footerCount;
                }

7、判斷當前 item 是否是 FooterView

/**
     * 判斷當前 item 是否是 FooterView
     */
    public boolean isFooterView(int position) {
        return footerCount != 0 && position >= (footerCount + mList.size());
    }

8、判斷當前 item 是否是 HeaderView

/**
     * 判斷當前 item 是否是 HeaderView
     */
    public boolean isHeaderView(int position) {
        return headerCount != 0 && position < headerCount;
    }

需加

class HeaderViewHolder extends RecyclerView.ViewHolder {

                        public HeaderViewHolder(@NonNull View itemView) {
                            super(itemView);
                        }
                    }

                    class FooterViewHolder extends RecyclerView.ViewHolder {

                            public FooterViewHolder(@NonNull View itemView) {
                                super(itemView);
                            }
                        }

問題一

當我們爲recyclerView設置表格佈局時，設置footer、header，如果不做任何處理就會出現下方錯誤

解決思路

1、通過setSpanSizeLookup重新設置顯示的列數
2、通過判斷當前view是footer、header,若是footer、header則佔取整列，否則佔取自己列

 @Override
    public void onAttachedToRecyclerView(@NonNull RecyclerView recyclerView) {
        RecyclerView.LayoutManager manager = recyclerView.getLayoutManager();
        if (manager instanceof GridLayoutManager) {
            //通過強轉將manager轉換成GridLayoutManager類型
            final GridLayoutManager gridLayoutManager = (GridLayoutManager) manager;
            //通過setSpanSizeLookup重新設置顯示的列數
            gridLayoutManager.setSpanSizeLookup(new GridLayoutManager.SpanSizeLookup() {

                @Override
                public int getSpanSize(int position) {
                    //通過判斷當前view是否是footer、header
                    //若是footer、header則佔取整列，否則佔取自己列
                  return (isHeaderView(position) || isFooterView(position)) ? gridLayoutManager.getSpanCount() : 1;
                }
            });
        }
    }

進階四：下拉刷新、上拉加載更多

下拉刷新：在RecyclerView佈局外層添加SwipeRefreshLayout
上拉加載更多：通過RecyclerView的addOnScrollListener來判斷房前滾動的狀態是否是最後一個Item，來進行加載更多

1、佈局

<android.support.v4.widget.SwipeRefreshLayout
            android:id="@+id/swipe_refresh_layout"
            android:layout_width="match_parent"
            android:layout_height="match_parent">
        <android.support.v7.widget.RecyclerView
                android:id="@+id/recycleview"
                android:layout_width="match_parent"
                android:layout_height="match_parent"/>
    </android.support.v4.widget.SwipeRefreshLayout>

2、通過swipeRefreshLayout.setOnRefreshListener來進行下拉刷新

swipeRefreshLayout.setOnRefreshListener(new SwipeRefreshLayout.OnRefreshListener() {
            @Override
            public void onRefresh() {
                Handler handler = new Handler();
                handler.postDelayed(new Runnable() {
                    @Override
                    public void run() {
                        /**
                         *要執行的操作
                         */
                        recyclerViewAdapter.addData(0, "我是刷新出來的數據");
                        swipeRefreshLayout.setRefreshing(false);
                        Toast.makeText(RecycleActivity.this, "下拉刷新成功", Toast.LENGTH_SHORT).show();
                    }
                }, 1500);//3秒後執行Runnable中的run方法
            }
        });

3、通過調用addOnScrollListener來進行加載更多

onScrollStateChanged(@NonNull RecyclerView recyclerView, int newState)//滾動狀態變化時的回調
onScrolled(@NonNull RecyclerView recyclerView, int dx, int dy)//滾動時回調

mRecyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
            /**
             *
             * @param recyclerView 當前滾動的recyclerView
             * @param newState 當前滾動的狀態
             *
             *  public static final int SCROLL_STATE_IDLE = 0;靜止沒有滾動
             *  public static final int SCROLL_STATE_DRAGGING = 1;正在被外部拖拽，即用戶滑動
             *  public static final int SCROLL_STATE_SETTLING = 2;//自動滾動
             *
             *
             */
            @Override
            public void onScrollStateChanged(@NonNull RecyclerView recyclerView, int newState) {
                //滾動狀態變化時的回調
                super.onScrollStateChanged(recyclerView, newState);
                //先判斷當前狀態是否已停止
                //判斷最後一條數據+1是否是集合的數據
                //判斷是否滑動到最底部
                if (newState == RecyclerView.SCROLL_STATE_IDLE && (lastVisibleItem + 1 == recyclerViewAdapter.getItemCount())) {
                    //判斷總數>0 說明可以加載更多
                    if (total > 0) {
                        //判斷total > count 說明還可以加載數據
                        if (total > count) {
                            Toast.makeText(RecycleActivity.this, "上拉加載", Toast.LENGTH_SHORT).show();
                            count += 10;//每次加載10條
                            getData();//加載的數據
                            recyclerViewAdapter.notifyDataSetChanged();//刷新適配器
                        } else {
                            Toast.makeText(RecycleActivity.this, "沒有數據加載了", Toast.LENGTH_SHORT).show();
                        }
                    } else {
                        Toast.makeText(RecycleActivity.this, "沒有數據加載了", Toast.LENGTH_SHORT).show();
                    }
                }
            }

            /**
             *
             * @param recyclerView 當前滾動的recyclerView
             * @param dx 水平滾動距離
             *           dx > 0 時爲手指向左滾動,列表滾動顯示右面的內容
             *           dx < 0 時爲手指向右滾動,列表滾動顯示左面的內容
             * @param dy 垂直滾動距離
             *           dy > 0 時爲手指向上滾動,列表滾動顯示下面的內容
             *           dy < 0 時爲手指向下滾動,列表滾動顯示上面的內容
             */
            @Override
            public void onScrolled(@NonNull RecyclerView recyclerView, int dx, int dy) {
                super.onScrolled(recyclerView, dx, dy);
                //滾動時回調
                //最後一個可見Item
                lastVisibleItem = mLinearLayoutManager.findLastVisibleItemPosition();
            }
        });

整體代碼

爲了更好的方便查，我把Activity和Adapter放在一起寫，開發中大家一定要分開邏輯來操作

package com.example.androidhightproject.module;

import android.content.Context;
import android.graphics.Rect;
import android.os.Bundle;
import android.os.Handler;
import android.support.annotation.NonNull;
import android.support.v4.widget.SwipeRefreshLayout;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.*;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.LinearLayout;
import android.widget.TextView;
import android.widget.Toast;
import com.example.androidhightproject.R;

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

/**
 * @author dongbo
 */
public class RecycleActivity extends AppCompatActivity {

    private List<String> mList = new ArrayList<>();
    private RecyclerView mRecyclerView;
    private SwipeRefreshLayout swipeRefreshLayout;
    private int lastVisibleItem;

    private int total = 30;
    private int count = 10;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_recycle);
        mRecyclerView = (RecyclerView) findViewById(R.id.recycleview);
        swipeRefreshLayout = (SwipeRefreshLayout) findViewById(R.id.swipe_refresh_layout);

        /**
         * 設置佈局管理器
         * 默認垂直排布  LinearLayoutManager.VERTICAL垂直  LinearLayoutManager.HORIZONTAL水平
         * boolean reverseLayout 默認是false 是否反轉
         *
         */
        LinearLayoutManager mLinearLayoutManager = new LinearLayoutManager(this, LinearLayoutManager.VERTICAL, false);
        mRecyclerView.setLayoutManager(mLinearLayoutManager);
        //設置縱向默認排列
//        mRecyclerView.setLayoutManager(new LinearLayoutManager(this, LinearLayoutManager.VERTICAL, false));
        //設置橫向默認排列,這裏需要注意改成橫向列表，分割線需要改成橫向
//        mRecyclerView.setLayoutManager(new LinearLayoutManager(this,LinearLayoutManager.HORIZONTAL,false));
        //設置表格佈局，這裏需要注意的是，有很多需求是根據返回的數據顯示錶格的數量，所以分割線需要自己重新定義
//        mRecyclerView.setLayoutManager(new GridLayoutManager(this, 3));
        //設置瀑布流顯示
//        mRecyclerView.setLayoutManager(new StaggeredGridLayoutManager(2, StaggeredGridLayoutManager.VERTICAL));
        //默認的分割線
        mRecyclerView.addItemDecoration(new DividerItemDecoration(this, DividerItemDecoration.VERTICAL));
        //設置自定義分割線
//        mRecyclerView.addItemDecoration(new SpaceItemDecoation(3));
        //設置刪除時的動畫
        mRecyclerView.setItemAnimator(new DefaultItemAnimator());
        RecyclerViewAdapter recyclerViewAdapter = new RecyclerViewAdapter(getData(), this);
        mRecyclerView.setAdapter(recyclerViewAdapter);
        swipeRefreshLayout.setColorSchemeResources(R.color.colorAccent);

        swipeRefreshLayout.setOnRefreshListener(new SwipeRefreshLayout.OnRefreshListener() {
            @Override
            public void onRefresh() {
                Handler handler = new Handler();
                handler.postDelayed(new Runnable() {
                    @Override
                    public void run() {
                        /**
                         *要執行的操作
                         */
                        recyclerViewAdapter.addData(0, "我是刷新出來的數據");
                        swipeRefreshLayout.setRefreshing(false);
                        Toast.makeText(RecycleActivity.this, "下拉刷新成功", Toast.LENGTH_SHORT).show();
                    }
                }, 1500);//3秒後執行Runnable中的run方法
            }
        });

        mRecyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
            /**
             *
             * @param recyclerView 當前滾動的recyclerView
             * @param newState 當前滾動的狀態
             *
             *  public static final int SCROLL_STATE_IDLE = 0;靜止沒有滾動
             *  public static final int SCROLL_STATE_DRAGGING = 1;正在被外部拖拽，即用戶滑動
             *  public static final int SCROLL_STATE_SETTLING = 2;//自動滾動
             *
             *
             */
            @Override
            public void onScrollStateChanged(@NonNull RecyclerView recyclerView, int newState) {
                //滾動狀態變化時的回調
                super.onScrollStateChanged(recyclerView, newState);
                //先判斷當前狀態是否已停止
                //判斷最後一條數據+1是否是集合的數據
                //判斷是否滑動到最底部
                Log.e("newState", newState + "");
                if (newState == RecyclerView.SCROLL_STATE_IDLE && (lastVisibleItem + 1 == recyclerViewAdapter.getItemCount())) {
                    //判斷總數>0 說明可以加載更多
                    if (total > 0) {
                        //判斷total > count 說明還可以加載數據
                        if (total > count) {
                            Toast.makeText(RecycleActivity.this, "上拉加載", Toast.LENGTH_SHORT).show();
                            count += 10;//每次加載10條
                            getData();//加載的數據
                            recyclerViewAdapter.notifyDataSetChanged();//刷新適配器
                        } else {
                            Toast.makeText(RecycleActivity.this, "沒有數據加載了", Toast.LENGTH_SHORT).show();
                        }
                    } else {
                        Toast.makeText(RecycleActivity.this, "沒有數據加載了", Toast.LENGTH_SHORT).show();
                    }
                }
            }

            /**
             *
             * @param recyclerView 當前滾動的recyclerView
             * @param dx 水平滾動距離
             *           dx > 0 時爲手指向左滾動,列表滾動顯示右面的內容
             *           dx < 0 時爲手指向右滾動,列表滾動顯示左面的內容
             * @param dy 垂直滾動距離
             *           dy > 0 時爲手指向上滾動,列表滾動顯示下面的內容
             *           dy < 0 時爲手指向下滾動,列表滾動顯示上面的內容
             */
            @Override
            public void onScrolled(@NonNull RecyclerView recyclerView, int dx, int dy) {
                super.onScrolled(recyclerView, dx, dy);
                //滾動時回調
                //最後一個可見Item
                Log.e("dx", dx + "");
                lastVisibleItem = mLinearLayoutManager.findLastVisibleItemPosition();
            }
        });
        recyclerViewAdapter.setOnItemClickListener(new RecyclerViewAdapter.OnItemClickListener() {
            @Override
            public void onItemClick(View view, int position) {
                Toast.makeText(RecycleActivity.this, "點擊了第" + position + "條", Toast.LENGTH_SHORT).show();
                recyclerViewAdapter.addData(position, "我是添加的數據");
            }

            @Override
            public void onItemLongClick(View view, int position) {
                Toast.makeText(RecycleActivity.this, "長按了第" + position + "條", Toast.LENGTH_SHORT).show();
                recyclerViewAdapter.removeData(position);
            }
        });

    }

    private List<String> getData() {
        for (int i = 0; i < 10; i++) {
            mList.add("測試數據" + i);
//            mList.add("照片地址");
        }
        return mList;
    }
}

class RecyclerViewAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> {

    /**
     * 首先要區分頭佈局、中間佈局、尾佈局三種不同的type，通過設置一個int值來判斷不同的佈局
     * 通過getItemViewType來返回type
     * 在onCreateViewHolder中根據不同的viewType顯示不同的佈局
     * 在onBindViewHolder根據不同的holder加載不同的數據
     * 注意：
     * 1、getItemCount這裏需要返回的集合的數量+header數量+footer數量
     * 2、當content佈局中加載數據是通過position獲取數據時需要將position-1
     */
    private List<String> mList;
    private Context mContext;
    private OnItemClickListener mOnItemClickListener;

    public static final int ITEM_TYPE_CONTENT = 0;
    public static final int ITEM_TYPE_FOOTER = 1;
    public static final int ITEM_TYPE_HEADER = 2;

    private int footerCount = 1;
    private int headerCount = 1;

    public RecyclerViewAdapter(List<String> mList, Context mContext) {
        //大部分只有數據與上下文
        this.mList = mList;
        this.mContext = mContext;
    }

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

    /**
     * 刪除某條數據
     *
     * @param position
     */
    public void removeData(int position) {
        notifyItemRemoved(position);
        mList.remove(position);
        notifyItemRangeChanged(position, mList.size());
    }

    /**
     * 在指定position添加數據
     *
     * @param position
     */
    public void addData(int position, String msg) {
        notifyItemInserted(position);
        if (mList == null) {
            mList = new ArrayList<>();
        }
        if (position < mList.size()) {
            //說明這裏是第一條
            mList.add(position, msg);
        } else {
            mList.add(msg);
            position = mList.size() - 1;
        }
        notifyItemRangeChanged(position, mList.size());
    }

    @Override
    public int getItemViewType(int position) {
        if (isHeaderView(position)) {
            return ITEM_TYPE_HEADER;
        } else if (isFooterView(position)) {
            return ITEM_TYPE_FOOTER;
        } else {
            return ITEM_TYPE_CONTENT;
        }
    }

    @Override
    public void onAttachedToRecyclerView(@NonNull RecyclerView recyclerView) {
        RecyclerView.LayoutManager manager = recyclerView.getLayoutManager();
        if (manager instanceof GridLayoutManager) {
            //通過強轉將manager轉換成GridLayoutManager類型
            final GridLayoutManager gridLayoutManager = (GridLayoutManager) manager;
            //通過setSpanSizeLookup重新設置顯示的列數
            gridLayoutManager.setSpanSizeLookup(new GridLayoutManager.SpanSizeLookup() {

                @Override
                public int getSpanSize(int position) {
                    //通過判斷當前view是否是footer、header
                    //若是footer、header則佔取整列，否則佔取自己列
                    return (isHeaderView(position) || isFooterView(position)) ? gridLayoutManager.getSpanCount() : 1;
                }
            });
        }
    }

    @NonNull
    @Override
    public RecyclerView.ViewHolder onCreateViewHolder(@NonNull ViewGroup viewGroup, int viewType) {
        /**
         * 主要負責把加載子項的佈局
         * 將xml定義的佈局實例化爲view對象
         */
        if (viewType == ITEM_TYPE_FOOTER) {
            View view = LayoutInflater.from(mContext).inflate(R.layout.recycler_footer_item, viewGroup, false);
            return new FooterViewHolder(view);
        } else if (viewType == ITEM_TYPE_HEADER) {
            View view = LayoutInflater.from(mContext).inflate(R.layout.recycler_header_item, viewGroup, false);
            return new HeaderViewHolder(view);
        } else if (viewType == ITEM_TYPE_CONTENT) {
            View view = LayoutInflater.from(mContext).inflate(R.layout.recyclerview_item, viewGroup, false);
            return new ContentViewHolder(view);
        }
        return null;
    }

    @Override
    public void onBindViewHolder(@NonNull RecyclerView.ViewHolder holder, int position) {
        //主要負責綁定數據
        if (holder instanceof HeaderViewHolder) {

        } else if (holder instanceof FooterViewHolder) {

        } else if (holder instanceof ContentViewHolder) {
//            Glide.with(mContext).load(mList.get(position-1)).into(((ContentViewHolder) holder).ivImage);
            ((ContentViewHolder) holder).tvItem.setText(mList.get(position - 1));
            ((ContentViewHolder) holder).llLayout.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    if (mOnItemClickListener != null) {
                        mOnItemClickListener.onItemClick(((ContentViewHolder) holder).llLayout, position - 1);
                    }
                }
            });
            ((ContentViewHolder) holder).llLayout.setOnLongClickListener(new View.OnLongClickListener() {
                @Override
                public boolean onLongClick(View v) {
                    if (mOnItemClickListener != null) {
                        mOnItemClickListener.onItemLongClick(((ContentViewHolder) holder).llLayout, position - 1);
                    }
                    return true;
                }
            });
        }

    }

    @Override
    public int getItemCount() {
        //返回集合的數量
        return mList.size() + headerCount + footerCount;
    }

    class HeaderViewHolder extends RecyclerView.ViewHolder {

        public HeaderViewHolder(@NonNull View itemView) {
            super(itemView);
        }
    }

    class FooterViewHolder extends RecyclerView.ViewHolder {

        public FooterViewHolder(@NonNull View itemView) {
            super(itemView);
        }
    }

    class ContentViewHolder extends RecyclerView.ViewHolder {
//        private final ImageView ivImage;

        private final TextView tvItem;
        private final LinearLayout llLayout;

        public ContentViewHolder(@NonNull View itemView) {
            super(itemView);
            tvItem = (TextView) itemView.findViewById(R.id.tv_item);
            llLayout = (LinearLayout) itemView.findViewById(R.id.ll_layout);
//            ivImage = (ImageView) itemView.findViewById(R.id.iv_image);
        }
    }

    /**
     * 通過在adapter定義接口實現回調
     */
    public interface OnItemClickListener {
        //點擊事件
        void onItemClick(View view, int position);

        //長按點擊事件
        void onItemLongClick(View view, int position);
    }

    /**
     * 判斷當前 item 是否是 FooterView
     */
    public boolean isFooterView(int position) {
        return footerCount != 0 && position >= (footerCount + mList.size());
    }

    /**
     * 判斷當前 item 是否是 HeaderView
     */
    public boolean isHeaderView(int position) {
        return headerCount != 0 && position < headerCount;
    }
}

class SpaceItemDecoation extends RecyclerView.ItemDecoration {
    private int space;

    public SpaceItemDecoation(int space) {
        this.space = space;
    }

    @Override
    public void getItemOffsets(@NonNull Rect outRect, @NonNull View view, @NonNull RecyclerView parent, @NonNull RecyclerView.State state) {
        super.getItemOffsets(outRect, view, parent, state);
        //如果不是第一個盒子設置一個居左和居下的邊距
        outRect.left = space;
        outRect.bottom = space;
        //大部分的需求都是3個 因爲第一個都是你設置個數的倍數，所以通過取餘來將左邊距設置爲0
        if (parent.getChildLayoutPosition(view) % 3 == 0) {
            outRect.left = 0;
        }
    }
}

作者：江湖小白_董
鏈接：https://www.jianshu.com/p/6fc3251c8157