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干货分享:Android RecyclerView(进阶篇)

干货分享:Android RecyclerView(进阶篇)

作者: 愿天堂没Android | 来源:发表于2020-05-09 15:50 被阅读0次

    进入进阶篇,相信大家通过之前的入门篇已经有了一定的认识了,接下来就是我们通过RecyclerView实现一些自己的功能

    可以先阅读Android RecyclerView(入门篇)

    目录

    • 点击事件
    • 添加、删除数据
    • 更丰富的条目展示(多条目展示)
    • 添加header 、footer
    • 下拉刷新、上拉加载更多

    进阶一:点击事件、长按事件(实现adapter和Activity之间的通信)

    RecyclerView要实现点击事件和长按事件可以在适配器中定义接口事件回调

    1、定义对象
    private OnItemClickListener mOnItemClickListener;
    2、写接口,并定义方法
    /**
    * 通过在adapter定义接口实现回调
    */
    public interface OnItemClickListener {
       //点击事件
       void onItemClick(View view, int position);
    
       //长按点击事件
       void onItemLongClick(View view, int position);
    }
    3、
    public void setOnItemClickListener(OnItemClickListener mOnItemClickListener) {
            this.mOnItemClickListener = mOnItemClickListener;
    }
    4、在adapter需要的地方调用事件
    if (mOnItemClickListener != null) {
       mOnItemClickListener.onItemClick(((ContentViewHolder) holder).llLayout, position - 1);
    }
    if (mOnItemClickListener != null) {
       mOnItemClickListener.onItemLongClick(((ContentViewHolder) holder).llLayout, position - 1);
    }
    5、Activity调用Adapter中的事件
    recyclerViewAdapter.setOnItemClickListener(new RecyclerViewAdapter.OnItemClickListener() {
                @Override
                public void onItemClick(View view, int position) {
                    Toast.makeText(RecycleActivity.this, "点击了第" + position + "条", Toast.LENGTH_SHORT).show();
                }
    
                @Override
                public void onItemLongClick(View view, int position) {
                    Toast.makeText(RecycleActivity.this, "长按了第" + position + "条", Toast.LENGTH_SHORT).show();
                }
    });
    
    

    进阶二:添加数据、删除某条数据

    这里需要了解到刷新界面的多种方式

            notifyDataSetChanged();//刷新整体布局
            notifyItemChanged(position);//刷新指定position,会重新调用onBindViewHolder来进行刷新,如果当前position在屏幕之外,则不会调用,当重新滚动到屏幕内,会重新调用
            notifyItemRangeChanged(position, 10);//刷新从position开始之后10条数据
            notifyItemInserted(position);//在第position处插入数据,这个插入时会有动画
            notifyItemMoved(position,5);//将当前position移动到position为5的地方,并且刷新
            notifyItemRangeInserted(3,10);//批量增加
            notifyItemRemoved(position);//删除第position条数据
            notifyItemRangeRemoved(position, 10);//批量删除
    
    
    /**
         * 删除某条数据
         *
         * @param position
         */
        public void removeData(int position) {
            mList.remove(position);
            notifyItemRemoved(position);
            notifyItemRangeChanged(position, mList.size());
    
        }
            /**
             * 在指定position添加数据
             *
             * @param position
             */
            public void addData(int position, String msg) {
                if (mList == null) {
                    mList = new ArrayList<>();
                }
                if (position < mList.size()) {
                    //说明这里是第一条
                    mList.add(position, msg);
                } else {
                    mList.add(msg);
                    position = mList.size() - 1;
                }
                notifyItemInserted(position);
                notifyItemRangeChanged(position, mList.size());
            }
    
    
    问题一:长按事件、点击事件同时发生
    解决思路

    在public boolean onLongClick(View v) {return true}
    需要消费掉这个长按事件 返回true

    进阶三:添加header、footer

    思路
    1、首先要区分头布局、中间布局、尾布局三种不同的type,通过设置一个int值来判断不同的布局
    2、通过getItemViewType来返回type
    3、在onCreateViewHolder中根据不同的viewType显示不同的布局
    4、在onBindViewHolder根据不同的holder加载不同的数据
    
    
    注意

    1、getItemCount这里需要返回的集合的数量+header数量+footer数量
    2、当content布局中加载数据是通过position获取数据时需要将
    position-1

    1、添加三种不同的type来区分不同的布局
    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、添加头、尾布局数量
    private int footerCount = 1;
    private int headerCount = 1;
    
    
    3、根据position获取Item的类型
    @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、根据不同的viewType显示不同的布局
     @NonNull
            @Override
            public RecyclerView.ViewHolder onCreateViewHolder(@NonNull ViewGroup viewGroup, int viewType) {
                /**
                 * 主要负责把加载子项的布局
                 * 将xml定义的布局实例化为view对象
                 */
                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、根据不同的ViewHolder加载不同的数据(注意content中通过position加载数据position需要-1)
     @Override
                public void onBindViewHolder(@NonNull RecyclerView.ViewHolder holder, int position) {
                    //主要负责绑定数据
                    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、返回的集合数量(务必加上header、footer)
    @Override
                    public int getItemCount() {
                        //返回集合的数量
                        return mList.size() + headerCount + footerCount;
                    }
    
    
    7、判断当前 item 是否是 FooterView
    /**
         * 判断当前 item 是否是 FooterView
         */
        public boolean isFooterView(int position) {
            return footerCount != 0 && position >= (footerCount + mList.size());
        }
    
    
    8、判断当前 item 是否是 HeaderView
    /**
         * 判断当前 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);
                                }
                            }
    
    
    问题一

    当我们为recyclerView设置表格布局时,设置footer、header,如果不做任何处理就会出现下方错误

    解决思路

    1、通过setSpanSizeLookup重新设置显示的列数
    2、通过判断当前view是footer、header,若是footer、header则占取整列,否则占取自己列

     @Override
        public void onAttachedToRecyclerView(@NonNull RecyclerView recyclerView) {
            RecyclerView.LayoutManager manager = recyclerView.getLayoutManager();
            if (manager instanceof GridLayoutManager) {
                //通过强转将manager转换成GridLayoutManager类型
                final GridLayoutManager gridLayoutManager = (GridLayoutManager) manager;
                //通过setSpanSizeLookup重新设置显示的列数
                gridLayoutManager.setSpanSizeLookup(new GridLayoutManager.SpanSizeLookup() {
    
                    @Override
                    public int getSpanSize(int position) {
                        //通过判断当前view是否是footer、header
                        //若是footer、header则占取整列,否则占取自己列
                      return (isHeaderView(position) || isFooterView(position)) ? gridLayoutManager.getSpanCount() : 1;
                    }
                });
            }
        }
    
    

    进阶四:下拉刷新、上拉加载更多

    下拉刷新:在RecyclerView布局外层添加SwipeRefreshLayout
    上拉加载更多:通过RecyclerView的addOnScrollListener来判断房前滚动的状态是否是最后一个Item,来进行加载更多

    1、布局
    <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、通过swipeRefreshLayout.setOnRefreshListener来进行下拉刷新
    swipeRefreshLayout.setOnRefreshListener(new SwipeRefreshLayout.OnRefreshListener() {
                @Override
                public void onRefresh() {
                    Handler handler = new Handler();
                    handler.postDelayed(new Runnable() {
                        @Override
                        public void run() {
                            /**
                             *要执行的操作
                             */
                            recyclerViewAdapter.addData(0, "我是刷新出来的数据");
                            swipeRefreshLayout.setRefreshing(false);
                            Toast.makeText(RecycleActivity.this, "下拉刷新成功", Toast.LENGTH_SHORT).show();
                        }
                    }, 1500);//3秒后执行Runnable中的run方法
                }
            });
    
    
    3、通过调用addOnScrollListener来进行加载更多

    onScrollStateChanged(@NonNull RecyclerView recyclerView, int newState)//滚动状态变化时的回调
    onScrolled(@NonNull RecyclerView recyclerView, int dx, int dy)//滚动时回调

    mRecyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
                /**
                 *
                 * @param recyclerView 当前滚动的recyclerView
                 * @param newState 当前滚动的状态
                 *
                 *  public static final int SCROLL_STATE_IDLE = 0;静止没有滚动
                 *  public static final int SCROLL_STATE_DRAGGING = 1;正在被外部拖拽,即用户滑动
                 *  public static final int SCROLL_STATE_SETTLING = 2;//自动滚动
                 *
                 *
                 */
                @Override
                public void onScrollStateChanged(@NonNull RecyclerView recyclerView, int newState) {
                    //滚动状态变化时的回调
                    super.onScrollStateChanged(recyclerView, newState);
                    //先判断当前状态是否已停止
                    //判断最后一条数据+1是否是集合的数据
                    //判断是否滑动到最底部
                    if (newState == RecyclerView.SCROLL_STATE_IDLE && (lastVisibleItem + 1 == recyclerViewAdapter.getItemCount())) {
                        //判断总数>0 说明可以加载更多
                        if (total > 0) {
                            //判断total > count 说明还可以加载数据
                            if (total > count) {
                                Toast.makeText(RecycleActivity.this, "上拉加载", Toast.LENGTH_SHORT).show();
                                count += 10;//每次加载10条
                                getData();//加载的数据
                                recyclerViewAdapter.notifyDataSetChanged();//刷新适配器
                            } else {
                                Toast.makeText(RecycleActivity.this, "没有数据加载了", Toast.LENGTH_SHORT).show();
                            }
                        } else {
                            Toast.makeText(RecycleActivity.this, "没有数据加载了", Toast.LENGTH_SHORT).show();
                        }
                    }
                }
    
                /**
                 *
                 * @param recyclerView 当前滚动的recyclerView
                 * @param dx 水平滚动距离
                 *           dx > 0 时为手指向左滚动,列表滚动显示右面的内容
                 *           dx < 0 时为手指向右滚动,列表滚动显示左面的内容
                 * @param dy 垂直滚动距离
                 *           dy > 0 时为手指向上滚动,列表滚动显示下面的内容
                 *           dy < 0 时为手指向下滚动,列表滚动显示上面的内容
                 */
                @Override
                public void onScrolled(@NonNull RecyclerView recyclerView, int dx, int dy) {
                    super.onScrolled(recyclerView, dx, dy);
                    //滚动时回调
                    //最后一个可见Item
                    lastVisibleItem = mLinearLayoutManager.findLastVisibleItemPosition();
                }
            });
    
    
    整体代码

    为了更好的方便查,我把Activity和Adapter放在一起写,开发中大家一定要分开逻辑来操作

    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);
    
            /**
             * 设置布局管理器
             * 默认垂直排布  LinearLayoutManager.VERTICAL垂直  LinearLayoutManager.HORIZONTAL水平
             * boolean reverseLayout 默认是false 是否反转
             *
             */
            LinearLayoutManager mLinearLayoutManager = new LinearLayoutManager(this, LinearLayoutManager.VERTICAL, false);
            mRecyclerView.setLayoutManager(mLinearLayoutManager);
            //设置纵向默认排列
    //        mRecyclerView.setLayoutManager(new LinearLayoutManager(this, LinearLayoutManager.VERTICAL, false));
            //设置横向默认排列,这里需要注意改成横向列表,分割线需要改成横向
    //        mRecyclerView.setLayoutManager(new LinearLayoutManager(this,LinearLayoutManager.HORIZONTAL,false));
            //设置表格布局,这里需要注意的是,有很多需求是根据返回的数据显示表格的数量,所以分割线需要自己重新定义
    //        mRecyclerView.setLayoutManager(new GridLayoutManager(this, 3));
            //设置瀑布流显示
    //        mRecyclerView.setLayoutManager(new StaggeredGridLayoutManager(2, StaggeredGridLayoutManager.VERTICAL));
            //默认的分割线
            mRecyclerView.addItemDecoration(new DividerItemDecoration(this, DividerItemDecoration.VERTICAL));
            //设置自定义分割线
    //        mRecyclerView.addItemDecoration(new SpaceItemDecoation(3));
            //设置删除时的动画
            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() {
                            /**
                             *要执行的操作
                             */
                            recyclerViewAdapter.addData(0, "我是刷新出来的数据");
                            swipeRefreshLayout.setRefreshing(false);
                            Toast.makeText(RecycleActivity.this, "下拉刷新成功", Toast.LENGTH_SHORT).show();
                        }
                    }, 1500);//3秒后执行Runnable中的run方法
                }
            });
    
            mRecyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
                /**
                 *
                 * @param recyclerView 当前滚动的recyclerView
                 * @param newState 当前滚动的状态
                 *
                 *  public static final int SCROLL_STATE_IDLE = 0;静止没有滚动
                 *  public static final int SCROLL_STATE_DRAGGING = 1;正在被外部拖拽,即用户滑动
                 *  public static final int SCROLL_STATE_SETTLING = 2;//自动滚动
                 *
                 *
                 */
                @Override
                public void onScrollStateChanged(@NonNull RecyclerView recyclerView, int newState) {
                    //滚动状态变化时的回调
                    super.onScrollStateChanged(recyclerView, newState);
                    //先判断当前状态是否已停止
                    //判断最后一条数据+1是否是集合的数据
                    //判断是否滑动到最底部
                    Log.e("newState", newState + "");
                    if (newState == RecyclerView.SCROLL_STATE_IDLE && (lastVisibleItem + 1 == recyclerViewAdapter.getItemCount())) {
                        //判断总数>0 说明可以加载更多
                        if (total > 0) {
                            //判断total > count 说明还可以加载数据
                            if (total > count) {
                                Toast.makeText(RecycleActivity.this, "上拉加载", Toast.LENGTH_SHORT).show();
                                count += 10;//每次加载10条
                                getData();//加载的数据
                                recyclerViewAdapter.notifyDataSetChanged();//刷新适配器
                            } else {
                                Toast.makeText(RecycleActivity.this, "没有数据加载了", Toast.LENGTH_SHORT).show();
                            }
                        } else {
                            Toast.makeText(RecycleActivity.this, "没有数据加载了", Toast.LENGTH_SHORT).show();
                        }
                    }
                }
    
                /**
                 *
                 * @param recyclerView 当前滚动的recyclerView
                 * @param dx 水平滚动距离
                 *           dx > 0 时为手指向左滚动,列表滚动显示右面的内容
                 *           dx < 0 时为手指向右滚动,列表滚动显示左面的内容
                 * @param dy 垂直滚动距离
                 *           dy > 0 时为手指向上滚动,列表滚动显示下面的内容
                 *           dy < 0 时为手指向下滚动,列表滚动显示上面的内容
                 */
                @Override
                public void onScrolled(@NonNull RecyclerView recyclerView, int dx, int dy) {
                    super.onScrolled(recyclerView, dx, dy);
                    //滚动时回调
                    //最后一个可见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, "点击了第" + position + "条", Toast.LENGTH_SHORT).show();
                    recyclerViewAdapter.addData(position, "我是添加的数据");
                }
    
                @Override
                public void onItemLongClick(View view, int position) {
                    Toast.makeText(RecycleActivity.this, "长按了第" + position + "条", Toast.LENGTH_SHORT).show();
                    recyclerViewAdapter.removeData(position);
                }
            });
    
        }
    
        private List<String> getData() {
            for (int i = 0; i < 10; i++) {
                mList.add("测试数据" + i);
    //            mList.add("照片地址");
            }
            return mList;
        }
    }
    
    class RecyclerViewAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> {
    
        /**
         * 首先要区分头布局、中间布局、尾布局三种不同的type,通过设置一个int值来判断不同的布局
         * 通过getItemViewType来返回type
         * 在onCreateViewHolder中根据不同的viewType显示不同的布局
         * 在onBindViewHolder根据不同的holder加载不同的数据
         * 注意:
         * 1、getItemCount这里需要返回的集合的数量+header数量+footer数量
         * 2、当content布局中加载数据是通过position获取数据时需要将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) {
            //大部分只有数据与上下文
            this.mList = mList;
            this.mContext = mContext;
        }
    
        public void setOnItemClickListener(OnItemClickListener mOnItemClickListener) {
            this.mOnItemClickListener = mOnItemClickListener;
        }
    
        /**
         * 删除某条数据
         *
         * @param position
         */
        public void removeData(int position) {
            notifyItemRemoved(position);
            mList.remove(position);
            notifyItemRangeChanged(position, mList.size());
        }
    
        /**
         * 在指定position添加数据
         *
         * @param position
         */
        public void addData(int position, String msg) {
            notifyItemInserted(position);
            if (mList == null) {
                mList = new ArrayList<>();
            }
            if (position < mList.size()) {
                //说明这里是第一条
                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) {
                //通过强转将manager转换成GridLayoutManager类型
                final GridLayoutManager gridLayoutManager = (GridLayoutManager) manager;
                //通过setSpanSizeLookup重新设置显示的列数
                gridLayoutManager.setSpanSizeLookup(new GridLayoutManager.SpanSizeLookup() {
    
                    @Override
                    public int getSpanSize(int position) {
                        //通过判断当前view是否是footer、header
                        //若是footer、header则占取整列,否则占取自己列
                        return (isHeaderView(position) || isFooterView(position)) ? gridLayoutManager.getSpanCount() : 1;
                    }
                });
            }
        }
    
        @NonNull
        @Override
        public RecyclerView.ViewHolder onCreateViewHolder(@NonNull ViewGroup viewGroup, int viewType) {
            /**
             * 主要负责把加载子项的布局
             * 将xml定义的布局实例化为view对象
             */
            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) {
            //主要负责绑定数据
            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() {
            //返回集合的数量
            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);
            }
        }
    
        /**
         * 通过在adapter定义接口实现回调
         */
        public interface OnItemClickListener {
            //点击事件
            void onItemClick(View view, int position);
    
            //长按点击事件
            void onItemLongClick(View view, int position);
        }
    
        /**
         * 判断当前 item 是否是 FooterView
         */
        public boolean isFooterView(int position) {
            return footerCount != 0 && position >= (footerCount + mList.size());
        }
    
        /**
         * 判断当前 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);
            //如果不是第一个盒子设置一个居左和居下的边距
            outRect.left = space;
            outRect.bottom = space;
            //大部分的需求都是3个 因为第一个都是你设置个数的倍数,所以通过取余来将左边距设置为0
            if (parent.getChildLayoutPosition(view) % 3 == 0) {
                outRect.left = 0;
            }
        }
    }
    
    

    最后

    到此对于RecyclerView你已经可以实现项目中的使用,还有很多需要我们来探索,比如回收复用机制、缓存机制等等,我也正在学习~
    喜欢记得点赞或者关注我哦, 有意见或者建议评论区见~

    (版权所有,来自网络,如有侵权,联系必删!!!)

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        本文标题:干货分享:Android RecyclerView(进阶篇)

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