RecyclerView--添加头部和底部

1.先构建WrapRecyclerAdapter

 /**
  * Description: 可以添加头部和底部的Adapter
  */
 public class WrapRecyclerAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> {
     private final static String TAG = "WrapRecyclerAdapter";

     /**
      * SparseArrays map integers to Objects.  Unlike a normal array of Objects,
      * there can be gaps in the indices.  It is intended to be more memory efficient
      * than using a HashMap to map Integers to Objects, both because it avoids
      * auto-boxing keys and its data structure doesn't rely on an extra entry object
      * for each mapping.
      *
      * SparseArray是一个<int , Object>的HashMap  比HashMap更高效
      */
     private SparseArray<View> mHeaderViews;
     private SparseArray<View> mFooterViews;

     // 基本的头部类型开始位置  用于viewType
     private static int BASE_ITEM_TYPE_HEADER = ;
     // 基本的底部类型开始位置  用于viewType
     private static int BASE_ITEM_TYPE_FOOTER = ;

     /**
      * 数据列表的Adapter
      */
     private RecyclerView.Adapter mAdapter;

     public WrapRecyclerAdapter(RecyclerView.Adapter adapter) {
         this.mAdapter = adapter;
         mHeaderViews = new SparseArray<>();
         mFooterViews = new SparseArray<>();
     }

     @Override
     public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {

         // viewType 可能就是 SparseArray 的key
         if (isHeaderViewType(viewType)) {
             View headerView = mHeaderViews.get(viewType);
             return createHeaderFooterViewHolder(headerView);
         }

         if (isFooterViewType(viewType)) {
             View footerView = mFooterViews.get(viewType);
             return createHeaderFooterViewHolder(footerView);
         }
         return mAdapter.onCreateViewHolder(parent, viewType);
     }

     /**
      * 是不是底部类型
      */
     private boolean isFooterViewType(int viewType) {
         int position = mFooterViews.indexOfKey(viewType);
         return position >= ;
     }

     /**
      * 创建头部或者底部的ViewHolder
      */
     private RecyclerView.ViewHolder createHeaderFooterViewHolder(View view) {
         return new RecyclerView.ViewHolder(view) {

         };
     }

     /**
      * 是不是头部类型
      */
     private boolean isHeaderViewType(int viewType) {
         int position = mHeaderViews.indexOfKey(viewType);
         return position >= ;
     }

     @Override
     public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {
         if (isHeaderPosition(position) || isFooterPosition(position)) {
             return;
         }

         // 计算一下位置
         final int adapterPosition = position - mHeaderViews.size();
         mAdapter.onBindViewHolder(holder, adapterPosition);

         // 设置点击和长按事件
         if (mItemClickListener != null) {
             holder.itemView.setOnClickListener(new View.OnClickListener() {
                 @Override
                 public void onClick(View v) {
                     mItemClickListener.onItemClick(v, adapterPosition);
                 }
             });
         }
         if (mLongClickListener != null) {
             holder.itemView.setOnLongClickListener(new View.OnLongClickListener() {
                 @Override
                 public boolean onLongClick(View v) {
                     return mLongClickListener.onLongClick(v, adapterPosition);
                 }
             });
         }
     }

     @Override
     public int getItemViewType(int position) {
         if (isHeaderPosition(position)) {
             // 直接返回position位置的key
             return mHeaderViews.keyAt(position);
         }
         if (isFooterPosition(position)) {
             // 直接返回position位置的key
             position = position - mHeaderViews.size() - mAdapter.getItemCount();
             return mFooterViews.keyAt(position);
         }
         // 返回列表Adapter的getItemViewType
         position = position - mHeaderViews.size();
         return mAdapter.getItemViewType(position);
     }

     /**
      * 是不是底部位置
      */
     private boolean isFooterPosition(int position) {
         return position >= (mHeaderViews.size() + mAdapter.getItemCount());
     }

     /**
      * 是不是头部位置
      */
     private boolean isHeaderPosition(int position) {
         return position < mHeaderViews.size();
     }

     @Override
     public int getItemCount() {
         // 条数三者相加 = 底部条数 + 头部条数 + Adapter的条数
         return mAdapter.getItemCount() + mHeaderViews.size() + mFooterViews.size();
     }

     /**
      * 获取列表的Adapter
      */
     private RecyclerView.Adapter getAdapter() {
         return mAdapter;
     }

     // 添加头部
     public void addHeaderView(View view) {
         int position = mHeaderViews.indexOfValue(view);
         if (position < ) {
             mHeaderViews.put(BASE_ITEM_TYPE_HEADER++, view);
         }
         notifyDataSetChanged();
     }

     // 添加底部
     public void addFooterView(View view) {
         int position = mFooterViews.indexOfValue(view);
         if (position < ) {
             mFooterViews.put(BASE_ITEM_TYPE_FOOTER++, view);
         }
         notifyDataSetChanged();
     }

     // 移除头部
     public void removeHeaderView(View view) {
         int index = mHeaderViews.indexOfValue(view);
         if (index < ) return;
         mHeaderViews.removeAt(index);
         notifyDataSetChanged();
     }

     // 移除底部
     public void removeFooterView(View view) {
         int index = mFooterViews.indexOfValue(view);
         if (index < ) return;
         mFooterViews.removeAt(index);
         notifyDataSetChanged();
     }

     /**
      * 解决GridLayoutManager添加头部和底部不占用一行的问题
      *
      * @param recycler
      * @version 1.0
      */
     public void adjustSpanSize(RecyclerView recycler) {
         if (recycler.getLayoutManager() instanceof GridLayoutManager) {
             final GridLayoutManager layoutManager = (GridLayoutManager) recycler.getLayoutManager();
             layoutManager.setSpanSizeLookup(new GridLayoutManager.SpanSizeLookup() {
                 @Override
                 public int getSpanSize(int position) {
                     boolean isHeaderOrFooter =
                             isHeaderPosition(position) || isFooterPosition(position);
                     return isHeaderOrFooter ? layoutManager.getSpanCount() : ;
                 }
             });
         }
     }

     /***************
      * 给条目设置点击和长按事件
      *********************/
     public OnItemClickListener mItemClickListener;
     public OnLongClickListener mLongClickListener;

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

     public void setOnLongClickListener(OnLongClickListener longClickListener) {
         this.mLongClickListener = longClickListener;
     }
 }

2.构建WrapRecyclerView

我们最好还是模仿ListView的结构搞就搞到西，自定义一个WrapRecyclerView，可以添加删除头部和底部View，这个就比较简单

 /**
  * Description: 可以添加头部和底部的RecyclerView
  */
 public class WrapRecyclerView extends RecyclerView {
     // 包裹了一层的头部底部Adapter
     private WrapRecyclerAdapter mWrapRecyclerAdapter;
     // 这个是列表数据的Adapter
     private Adapter mAdapter;

     // 增加一些通用功能
     // 空列表数据应该显示的空View
     // 正在加载数据页面，也就是正在获取后台接口页面
     private View mEmptyView, mLoadingView;

     public WrapRecyclerView(Context context) {
         super(context);
     }

     public WrapRecyclerView(Context context, @Nullable AttributeSet attrs) {
         super(context, attrs);
     }

     public WrapRecyclerView(Context context, @Nullable AttributeSet attrs, int defStyle) {
         super(context, attrs, defStyle);
     }

     @Override
     public void setAdapter(Adapter adapter) {
         // 为了防止多次设置Adapter
         if (mAdapter != null) {
             mAdapter.unregisterAdapterDataObserver(mDataObserver);
             mAdapter = null;
         }

         this.mAdapter = adapter;

         if (adapter instanceof WrapRecyclerAdapter) {
             mWrapRecyclerAdapter = (WrapRecyclerAdapter) adapter;
         } else {
             mWrapRecyclerAdapter = new WrapRecyclerAdapter(adapter);
         }

         super.setAdapter(mWrapRecyclerAdapter);

         // 注册一个观察者
         mAdapter.registerAdapterDataObserver(mDataObserver);

         // 解决GridLayout添加头部和底部也要占据一行
         mWrapRecyclerAdapter.adjustSpanSize(this);

         // 加载数据页面
         if (mLoadingView != null && mLoadingView.getVisibility() == View.VISIBLE) {
             mLoadingView.setVisibility(View.GONE);
         }

         if (mItemClickListener != null) {
             mWrapRecyclerAdapter.setOnItemClickListener(mItemClickListener);
         }

         if (mLongClickListener != null) {
             mWrapRecyclerAdapter.setOnLongClickListener(mLongClickListener);
         }
     }

     // 添加头部
     public void addHeaderView(View view) {
         // 如果没有Adapter那么就不添加，也可以选择抛异常提示
         // 让他必须先设置Adapter然后才能添加，这里是仿照ListView的处理方式
         if (mWrapRecyclerAdapter != null) {
             mWrapRecyclerAdapter.addHeaderView(view);
         }
     }

     // 添加底部
     public void addFooterView(View view) {
         if (mWrapRecyclerAdapter != null) {
             mWrapRecyclerAdapter.addFooterView(view);
         }
     }

     // 移除头部
     public void removeHeaderView(View view) {
         if (mWrapRecyclerAdapter != null) {
             mWrapRecyclerAdapter.removeHeaderView(view);
         }
     }

     // 移除底部
     public void removeFooterView(View view) {
         if (mWrapRecyclerAdapter != null) {
             mWrapRecyclerAdapter.removeFooterView(view);
         }
     }

     private AdapterDataObserver mDataObserver = new AdapterDataObserver() {
         @Override
         public void onChanged() {
             if (mAdapter == null) return;
             // 观察者  列表Adapter更新 包裹的也需要更新不然列表的notifyDataSetChanged没效果
             if (mWrapRecyclerAdapter != mAdapter)
                 mWrapRecyclerAdapter.notifyDataSetChanged();

             dataChanged();
         }

         @Override
         public void onItemRangeRemoved(int positionStart, int itemCount) {
             if (mAdapter == null) return;
             // 观察者  列表Adapter更新 包裹的也需要更新不然列表的notifyDataSetChanged没效果
             if (mWrapRecyclerAdapter != mAdapter)
                 mWrapRecyclerAdapter.notifyItemRemoved(positionStart);
             dataChanged();
         }

         @Override
         public void onItemRangeMoved(int fromPosition, int toPosition, int itemCount) {
             if (mAdapter == null) return;
             // 观察者  列表Adapter更新 包裹的也需要更新不然列表的notifyItemMoved没效果
             if (mWrapRecyclerAdapter != mAdapter)
                 mWrapRecyclerAdapter.notifyItemMoved(fromPosition, toPosition);
             dataChanged();
         }

         @Override
         public void onItemRangeChanged(int positionStart, int itemCount) {
             if (mAdapter == null) return;
             // 观察者  列表Adapter更新 包裹的也需要更新不然列表的notifyItemChanged没效果
             if (mWrapRecyclerAdapter != mAdapter)
                 mWrapRecyclerAdapter.notifyItemChanged(positionStart);
             dataChanged();
         }

         @Override
         public void onItemRangeChanged(int positionStart, int itemCount, Object payload) {
             if (mAdapter == null) return;
             // 观察者  列表Adapter更新 包裹的也需要更新不然列表的notifyItemChanged没效果
             if (mWrapRecyclerAdapter != mAdapter)
                 mWrapRecyclerAdapter.notifyItemChanged(positionStart, payload);
             dataChanged();
         }

         @Override
         public void onItemRangeInserted(int positionStart, int itemCount) {
             if (mAdapter == null) return;
             // 观察者  列表Adapter更新 包裹的也需要更新不然列表的notifyItemInserted没效果
             if (mWrapRecyclerAdapter != mAdapter)
                 mWrapRecyclerAdapter.notifyItemInserted(positionStart);
             dataChanged();
         }
     };

     /**
      * 添加一个空列表数据页面
      */
     public void addEmptyView(View emptyView) {
         this.mEmptyView = emptyView;
     }

     /**
      * 添加一个正在加载数据的页面
      */
     public void addLoadingView(View loadingView) {
         this.mLoadingView = loadingView;
         mLoadingView.setVisibility(View.VISIBLE);
     }

     /**
      * Adapter数据改变的方法
      */
     private void dataChanged() {
         if (mAdapter.getItemCount() == ) {
             // 没有数据
             if (mEmptyView != null) {
                 mEmptyView.setVisibility(VISIBLE);
             }
         } else {
             // 没有数据
             if (mEmptyView != null) {
                 mEmptyView.setVisibility(GONE);
             }
         }
     }

     /***************
      * 给条目设置点击和长按事件
      *********************/
     public com.zzw.framelibray.recyclerview.adapter.OnItemClickListener mItemClickListener;
     public com.zzw.framelibray.recyclerview.adapter.OnLongClickListener mLongClickListener;

     public void setOnItemClickListener(com.zzw.framelibray.recyclerview.adapter.OnItemClickListener itemClickListener) {
         this.mItemClickListener = itemClickListener;

         if (mWrapRecyclerAdapter != null) {
             mWrapRecyclerAdapter.setOnItemClickListener(mItemClickListener);
         }
     }

     public void setOnLongClickListener(com.zzw.framelibray.recyclerview.adapter.OnLongClickListener longClickListener) {
         this.mLongClickListener = longClickListener;

         if (mWrapRecyclerAdapter != null) {
             mWrapRecyclerAdapter.setOnLongClickListener(mLongClickListener);
         }
     }
 }

3.使用：

 <?xml version="1.0" encoding="utf-8"?>
 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
     android:orientation="vertical" android:layout_width="match_parent"
     android:layout_height="match_parent">

     <com.zzw.framelibray.recyclerview.view.WrapRecyclerView
         android:id="@+id/wrap_recycler_view"
         android:layout_width="match_parent"
         android:layout_height="match_parent"

         />

 </LinearLayout>

Activity

 public class HeaderFooterActivity extends AppCompatActivity implements OnItemClickListener {

     private WrapRecyclerView mRecyclerView;
     private List<People> mData;

     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_recycler_view);
         mRecyclerView = (WrapRecyclerView) findViewById(R.id.wrap_recycler_view);
         mRecyclerView.setLayoutManager(new LinearLayoutManager(this));

         mData =new ArrayList<>();
         mData.add(new People());
         mData.add(new People());
         mData.add(new People());

         PeopleListAdapter listAdapter = new PeopleListAdapter(this, mData);

         // 添加头部和底部 需要 包裹Adapter，才能添加头部和底部
         WrapRecyclerAdapter wrapRecyclerAdapter = new WrapRecyclerAdapter(listAdapter);
         mRecyclerView.setAdapter(wrapRecyclerAdapter);

         wrapRecyclerAdapter.setOnItemClickListener(this);

         // 添加头部和底部
         wrapRecyclerAdapter.addHeaderView(LayoutInflater.from(this).inflate(R.layout.layout_header,mRecyclerView,false));
         wrapRecyclerAdapter.addFooterView(LayoutInflater.from(this).inflate(R.layout.layout_header,mRecyclerView,false));
     }

     @Override
     public void onItemClick(View view, int position) {
         Toast.makeText(this, "" + mData.get(position).name, Toast.LENGTH_SHORT).show();
     }

     class PeopleListAdapter extends CommonRecyclerAdapter<People> {

         public PeopleListAdapter(Context context, List<People> datas) {
             super(context, datas, R.layout.channel_list_item);
         }

         @Override
         public void convert(ViewHolder holder, People item, int position) {
             holder.setText(R.id.action_btn, item.name+position);
         }
     }

     class People{
         String name="王伟:";
     }
 }