ListView和RecyclerView的Adapter封装

刺骨的言语ヽ痛彻心扉 2022-07-14 06:11 247阅读 0赞

# 原文链接 #

[Android 快速开发系列 打造万能的ListView GridView 适配器][Android _ _ListView GridView]

[为RecyclerView打造通用Adapter 让RecyclerView更加好用][RecyclerView_Adapter _RecyclerView]

[Android 优雅的为RecyclerView添加HeaderView和FooterView][Android _RecyclerView_HeaderView_FooterView]

[Android LRecyclerView实现下拉刷新，滑动到底部自动加载更多][Android LRecyclerView]

[RecyclerView添加Header的正确方式][RecyclerView_Header]

1.  Adapter的封装
2.  添加header和footer
3.  加载更多/上拉加载/滚动加载
4.  下拉刷新
5.  多种Item Type 数据绑定
6.  增加onItemClickListener , onItenLongClickListener

多种ItemViewType，一般我们的写法是：

复写getItemViewType，根据我们的bean去返回不同的类型  
onCreateViewHolder中根据itemView去生成不同的ViewHolder

如果大家还记得，我们的ViewHolder是通用的，唯一依赖的就是个layoutId。那么上述第二条就变成，根据不同的itemView告诉我用哪个layoutId即可，生成viewholder这种事我们通用adapter来做。

指明不同的Bean返回什么itemViewType,不同的itemView所对应的layoutId

## LoadmoreWrapper加载更多 ##

装饰者模式

//设置加载更多的布局
    public LoadmoreWrapper setLoadMoreView(View loadMoreView)
        {
            mLoadMoreView = loadMoreView;
            return this;
        }
    
        public LoadmoreWrapper setLoadMoreView(int layoutId)
        {
            mLoadMoreLayoutId = layoutId;
            return this;
        }

//设置了加载更多的布局文件或者布局文件的id，则有加载更多
     private boolean hasLoadMore()
        {
            return mLoadMoreView != null || mLoadMoreLayoutId != 0;
        }
    
    //设置加载更多的布局，并且当前的位置position大于等于列表的条目数
        private boolean isShowLoadMore(int position)
        {
            return hasLoadMore() && (position >= mInnerAdapter.getItemCount());
        }

//如果滑动到底部，返回加载更多的itemtype
     @Override
        public int getItemViewType(int position)
        {
            if (isShowLoadMore(position))
            {
                return ITEM_TYPE_LOAD_MORE;
            }
            return mInnerAdapter.getItemViewType(position);
        }

//根据不同的itemtype创建不同的viewholder
    @Override
        public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType)
        {
            if (viewType == ITEM_TYPE_LOAD_MORE)
            {
                ViewHolder holder;
                if (mLoadMoreView != null)
                {
                    holder = ViewHolder.createViewHolder(parent.getContext(), mLoadMoreView);
                } else
                {
                    holder = ViewHolder.createViewHolder(parent.getContext(), parent, mLoadMoreLayoutId);
                }
                return holder;
            }
            return mInnerAdapter.onCreateViewHolder(parent, viewType);
        }

//如果当前的位置是加载更多的位置，则加载下一页数据
     @Override
        public void onBindViewHolder(RecyclerView.ViewHolder holder, int position)
        {
            if (isShowLoadMore(position))
            {
                if (mOnLoadMoreListener != null)
                {
                    mOnLoadMoreListener.onLoadMoreRequested();
                }
                return;
            }
            mInnerAdapter.onBindViewHolder(holder, position);
        }

//设置了加载更多布局，则列表条目数加1
     @Override
        public int getItemCount()
        {
            return mInnerAdapter.getItemCount() + (hasLoadMore() ? 1 : 0);
        }

## LoadingFooter ##

public class LoadingFooter extends RelativeLayout { 
    
        protected State mState = State.Normal;
        private View mLoadingView;
        private View mNetworkErrorView;
        private View mTheEndView;
        private AVLoadingIndicatorView mLoadingProgress;
        private TextView mLoadingText;
    
        public LoadingFooter(Context context) {
            super(context);
            init(context);
        }
    
        public LoadingFooter(Context context, AttributeSet attrs) {
            super(context, attrs);
            init(context);
        }
    
        public LoadingFooter(Context context, AttributeSet attrs, int defStyleAttr) {
            super(context, attrs, defStyleAttr);
            init(context);
        }
    
        public void init(Context context) {
    
            inflate(context, R.layout.layout_recyclerview_list_footer, this);
            setOnClickListener(null);
    
            setState(State.Normal, true);
        }
    
        public State getState() {
            return mState;
        }
    
        public void setState(State status ) {
            setState(status, true);
        }
    
        /** * 设置状态 * * @param status * @param showView 是否展示当前View */
        public void setState(State status, boolean showView) {
            if (mState == status) {
                return;
            }
            mState = status;
    
            switch (status) {
    
                case Normal:
                    setOnClickListener(null);
                    if (mLoadingView != null) {
                        mLoadingView.setVisibility(GONE);
                    }
    
                    if (mTheEndView != null) {
                        mTheEndView.setVisibility(GONE);
                    }
    
                    if (mNetworkErrorView != null) {
                        mNetworkErrorView.setVisibility(GONE);
                    }
    
                    break;
                case Loading:
                    setOnClickListener(null);
                    if (mTheEndView != null) {
                        mTheEndView.setVisibility(GONE);
                    }
    
                    if (mNetworkErrorView != null) {
                        mNetworkErrorView.setVisibility(GONE);
                    }
    
                    if (mLoadingView == null) {
                        ViewStub viewStub = (ViewStub) findViewById(R.id.loading_viewstub);
                        mLoadingView = viewStub.inflate();
    
                        mLoadingProgress = (AVLoadingIndicatorView) mLoadingView.findViewById(R.id.loading_progress);
                        mLoadingText = (TextView) mLoadingView.findViewById(R.id.loading_text);
                    } else {
                        mLoadingView.setVisibility(VISIBLE);
                    }
    
                    mLoadingView.setVisibility(showView ? VISIBLE : GONE);
    
                    mLoadingProgress.setVisibility(View.VISIBLE);
                    mLoadingText.setText(R.string.list_footer_loading);
                    break;
                case TheEnd:
                    setOnClickListener(null);
                    if (mLoadingView != null) {
                        mLoadingView.setVisibility(GONE);
                    }
    
                    if (mNetworkErrorView != null) {
                        mNetworkErrorView.setVisibility(GONE);
                    }
    
                    if (mTheEndView == null) {
                        ViewStub viewStub = (ViewStub) findViewById(R.id.end_viewstub);
                        mTheEndView = viewStub.inflate();
                    } else {
                        mTheEndView.setVisibility(VISIBLE);
                    }
    
                    mTheEndView.setVisibility(showView ? VISIBLE : GONE);
                    break;
                case NetWorkError:
    
                    if (mLoadingView != null) {
                        mLoadingView.setVisibility(GONE);
                    }
    
                    if (mTheEndView != null) {
                        mTheEndView.setVisibility(GONE);
                    }
    
                    if (mNetworkErrorView == null) {
                        ViewStub viewStub = (ViewStub) findViewById(R.id.network_error_viewstub);
                        mNetworkErrorView = viewStub.inflate();
                    } else {
                        mNetworkErrorView.setVisibility(VISIBLE);
                    }
    
                    mNetworkErrorView.setVisibility(showView ? VISIBLE : GONE);
                    break;
                default:
    
                    break;
            }
        }
    
        public enum State {
            Normal/**正常*/, 
            TheEnd/**加载到最底了*/, 
            Loading/**加载中..*/, 
            NetWorkError/**网络异常*/
        }
    }

布局文件

<?xml version="1.0" encoding="utf-8"?>
    <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:id="@+id/loading_view" android:layout_width="match_parent" android:layout_height="@dimen/dp_60" android:gravity="center" android:orientation="vertical">
    
        <ViewStub android:id="@+id/loading_viewstub" android:layout_width="match_parent" android:layout_height="@dimen/dp_60" android:layout="@layout/layout_recyclerview_list_footer_loading" />
    
        <ViewStub android:id="@+id/end_viewstub" android:layout_width="match_parent" android:layout_height="@dimen/dp_60" android:layout="@layout/layout_recyclerview_list_footer_end" />
    
        <ViewStub android:id="@+id/network_error_viewstub" android:layout_width="match_parent" android:layout_height="@dimen/dp_60" android:layout="@layout/layout_recyclerview_list_footer_network_error" />
    
    </LinearLayout>

## RecyclerViewStateUtils ##

package com.github.jdsjlzx.util;
    
    import android.app.Activity;
    import android.support.v7.widget.RecyclerView;
    import android.view.View;
    
    import com.github.jdsjlzx.recyclerview.LRecyclerView;
    import com.github.jdsjlzx.recyclerview.LRecyclerViewAdapter;
    import com.github.jdsjlzx.view.LoadingFooter;
    
    /** * 分页展示数据时，RecyclerView的FooterView State 操作工具类 * RecyclerView一共有几种State：Normal/Loading/Error/TheEnd * * @author lizhixian * @time 16/9/10 09:56 */
    public class RecyclerViewStateUtils { 
    
        /** * 设置LRecyclerViewAdapter的FooterView State * * @param instance context * @param recyclerView recyclerView * @param pageSize 分页展示时，recyclerView每一页的数量 * @param state FooterView State * @param errorListener FooterView处于Error状态时的点击事件 */
        public static void setFooterViewState(Activity instance, RecyclerView recyclerView, int
                pageSize, LoadingFooter.State state, View.OnClickListener errorListener) {
            if (instance == null || instance.isFinishing()) {
                return;
            }
    
            RecyclerView.Adapter outerAdapter = recyclerView.getAdapter();
    
            if (outerAdapter == null || !(outerAdapter instanceof LRecyclerViewAdapter)) {
                return;
            }
    
            LRecyclerViewAdapter lRecyclerViewAdapter = (LRecyclerViewAdapter) outerAdapter;
    
            //只有一页的时候，就别加什么FooterView了
            if (lRecyclerViewAdapter.getInnerAdapter().getItemCount() < pageSize) {
                return;
            }
    
            LoadingFooter footerView;
            //已经有footerView了
            if (lRecyclerViewAdapter.getFooterViewsCount() > 0) {
                footerView = (LoadingFooter) lRecyclerViewAdapter.getFooterView();
                footerView.setState(state);
                footerView.setVisibility(View.VISIBLE);
    
                if (state == LoadingFooter.State.NetWorkError) {
                    footerView.setOnClickListener(errorListener);
                } else if (state == LoadingFooter.State.TheEnd) {
                    ((LRecyclerView) recyclerView).setNoMore(true);
                }
    
            }
            recyclerView.scrollToPosition(lRecyclerViewAdapter.getItemCount() - 1);
    
        }
    
        /** * 设置LRecyclerViewAdapter的FooterView State * * @param instance context * @param recyclerView recyclerView * @param pageSize 分页展示时，recyclerView每一页的数量 * @param state FooterView State * @param errorListener FooterView处于Error状态时的点击事件 */
        public static void setFooterViewState2(Activity instance, RecyclerView recyclerView, int
                pageSize, LoadingFooter.State state, View.OnClickListener errorListener) {
    
            if (instance == null || instance.isFinishing()) {
                return;
            }
    
            RecyclerView.Adapter outerAdapter = recyclerView.getAdapter();
    
            if (outerAdapter == null || !(outerAdapter instanceof LRecyclerViewAdapter)) {
                return;
            }
    
            LRecyclerViewAdapter lRecyclerViewAdapter = (LRecyclerViewAdapter) outerAdapter;
    
            LoadingFooter footerView;
    
            //已经有footerView了
            if (lRecyclerViewAdapter.getFooterViewsCount() > 0) {
                footerView = (LoadingFooter) lRecyclerViewAdapter.getFooterView();
                footerView.setState(state);
    
                if (state == LoadingFooter.State.NetWorkError) {
                    footerView.setOnClickListener(errorListener);
                }
                recyclerView.scrollToPosition(0);
            } else {
                footerView = new LoadingFooter(instance);
                footerView.setState(state);
    
                if (state == LoadingFooter.State.NetWorkError) {
                    footerView.setOnClickListener(errorListener);
                }
    
                lRecyclerViewAdapter.addFooterView(footerView);
                recyclerView.scrollToPosition(0);
            }
        }
    
        /** * 获取当前RecyclerView.FooterView的状态 * * @param recyclerView */
        public static LoadingFooter.State getFooterViewState(RecyclerView recyclerView) {
    
            RecyclerView.Adapter outerAdapter = recyclerView.getAdapter();
            if (outerAdapter != null && outerAdapter instanceof LRecyclerViewAdapter) {
                if (((LRecyclerViewAdapter) outerAdapter).getFooterViewsCount() > 0) {
                    LoadingFooter footerView = (LoadingFooter) ((LRecyclerViewAdapter) outerAdapter)
                            .getFooterView();
                    return footerView.getState();
                }
            }
    
            return LoadingFooter.State.Normal;
        }
    
        /** * 设置当前RecyclerView.FooterView的状态 * * @param recyclerView * @param state */
        public static void setFooterViewState(RecyclerView recyclerView, LoadingFooter.State state) {
            RecyclerView.Adapter outerAdapter = recyclerView.getAdapter();
            if (outerAdapter != null && outerAdapter instanceof LRecyclerViewAdapter) {
                if (((LRecyclerViewAdapter) outerAdapter).getFooterViewsCount() > 0) {
                    LoadingFooter footerView = (LoadingFooter) ((LRecyclerViewAdapter) outerAdapter)
                            .getFooterView();
                    footerView.setState(state);
                }
            }
        }
    }

## LRecyclerViewAdapter ##

package com.github.jdsjlzx.recyclerview;
    
    import android.support.v7.widget.GridLayoutManager;
    import android.support.v7.widget.RecyclerView;
    import android.support.v7.widget.StaggeredGridLayoutManager;
    import android.view.View;
    import android.view.ViewGroup;
    
    import com.github.jdsjlzx.interfaces.OnItemClickListener;
    import com.github.jdsjlzx.interfaces.OnItemLongClickListener;
    import com.github.jdsjlzx.view.ArrowRefreshHeader;
    
    import java.util.ArrayList;
    import java.util.List;
    
    /** * RecyclerView.Adapter with Header and Footer * */
    public class LRecyclerViewAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> { 
    
        private static final int TYPE_REFRESH_HEADER = 10000;
        private static final int TYPE_NORMAL = 0;
        private static final int TYPE_FOOTER_VIEW = 10001;
        private static final int HEADER_INIT_INDEX = 10002;
        private static List<Integer> mHeaderTypes = new ArrayList<>();
    
        private ArrowRefreshHeader mRefreshHeader;
    
        private OnItemClickListener mOnItemClickListener;
        private OnItemLongClickListener mOnItemLongClickListener;
    
        /** * RecyclerView使用的，真正的Adapter */
        private RecyclerView.Adapter mInnerAdapter;
    
        private ArrayList<View> mHeaderViews = new ArrayList<>();
        private ArrayList<View> mFooterViews = new ArrayList<>();
    
    
        public LRecyclerViewAdapter(RecyclerView.Adapter innerAdapter) {
            this.mInnerAdapter = innerAdapter;
        }
    
        public void setRefreshHeader(ArrowRefreshHeader refreshHeader){
            mRefreshHeader = refreshHeader;
        }
    
        public RecyclerView.Adapter getInnerAdapter() {
            return mInnerAdapter;
        }
    
        public void addHeaderView(View view) {
    
            if (view == null) {
                throw new RuntimeException("header is null");
            }
    
            mHeaderTypes.add(HEADER_INIT_INDEX + mHeaderViews.size());
            mHeaderViews.add(view);
        }
    
        public void addFooterView(View view) {
    
            if (view == null) {
                throw new RuntimeException("footer is null");
            }
            if (getFooterViewsCount() > 0) {
                removeFooterView(getFooterView());
            }
            mFooterViews.add(view);
            //this.notifyDataSetChanged();
        }
    
        /** * 根据header的ViewType判断是哪个header * @param itemType * @return */
        private View getHeaderViewByType(int itemType) {
            if(!isHeaderType(itemType)) {
                return null;
            }
            return mHeaderViews.get(itemType - HEADER_INIT_INDEX);
        }
    
        /** * 判断一个type是否为HeaderType * @param itemViewType * @return */
        private boolean isHeaderType(int itemViewType) {
            return  mHeaderViews.size() > 0 &&  mHeaderTypes.contains(itemViewType);
        }
    
        /** * 返回第一个FootView * @return */
        public View getFooterView() {
            return  getFooterViewsCount()>0 ? mFooterViews.get(0) : null;
        }
    
        /** * 返回第一个HeaderView * @return */
        public View getHeaderView() {
            return  getHeaderViewsCount()>0 ? mHeaderViews.get(0) : null;
        }
    
        public ArrayList<View> getHeaderViews() {
            return mHeaderViews;
        }
    
        public void removeHeaderView(View view) {
            mHeaderViews.remove(view);
            this.notifyDataSetChanged();
        }
    
        public void removeFooterView(View view) {
            mFooterViews.remove(view);
            this.notifyDataSetChanged();
        }
    
        public int getHeaderViewsCount() {
            return mHeaderViews.size();
        }
    
        public int getFooterViewsCount() {
            return mFooterViews.size();
        }
    
        public boolean isHeader(int position) {
            return position >= 1 && position < mHeaderViews.size() + 1;
        }
    
        public boolean isRefreshHeader(int position) {
            return position == 0;
        }
    
        public boolean isFooter(int position) {
            int lastPosition = getItemCount() - getFooterViewsCount();
            return getFooterViewsCount() > 0 && position >= lastPosition;
        }
    
        @Override
        public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
    
            if (viewType == TYPE_REFRESH_HEADER) {
                return new ViewHolder(mRefreshHeader);
            } else if (isHeaderType(viewType)) {
                return new ViewHolder(getHeaderViewByType(viewType));
            } else if (viewType == TYPE_FOOTER_VIEW) {
                return new ViewHolder(mFooterViews.get(0));
            }
            return mInnerAdapter.onCreateViewHolder(parent, viewType);
        }
    
        @Override
        public void onBindViewHolder(final RecyclerView.ViewHolder holder, int position) {
            if (isHeader(position) || isRefreshHeader(position)) {
                return;
            }
            final int adjPosition = position - (getHeaderViewsCount() + 1);
            int adapterCount;
            if (mInnerAdapter != null) {
                adapterCount = mInnerAdapter.getItemCount();
                if (adjPosition < adapterCount) {
                    mInnerAdapter.onBindViewHolder(holder, adjPosition);
    
                    if (mOnItemClickListener != null) {
                        holder.itemView.setOnClickListener(new View.OnClickListener()  {
                            @Override
                            public void onClick(View v)
                            {
                                mOnItemClickListener.onItemClick(holder.itemView, adjPosition);
                            }
                        });
    
                    }
    
                    if (mOnItemLongClickListener != null) {
                        holder.itemView.setOnLongClickListener(new View.OnLongClickListener() {
                            @Override
                            public boolean onLongClick(View v)
                            {
                                mOnItemLongClickListener.onItemLongClick(holder.itemView, adjPosition);
                                return true;
                            }
                        });
                    }
    
                }
            }
        }
    
        @Override
        public void onBindViewHolder(final RecyclerView.ViewHolder holder, int position, List<Object> payloads) {
            if (payloads.isEmpty()) {
                onBindViewHolder(holder,position);
            } else {
    
                if (isHeader(position) || isRefreshHeader(position)) {
                    return;
                }
                final int adjPosition = position - (getHeaderViewsCount() + 1);
                int adapterCount;
                if (mInnerAdapter != null) {
                    adapterCount = mInnerAdapter.getItemCount();
                    if (adjPosition < adapterCount) {
                        mInnerAdapter.onBindViewHolder(holder, adjPosition, payloads);
                    }
                }
    
            }
        }
    
        @Override
        public int getItemCount() {
            if (mInnerAdapter != null) {
                return getHeaderViewsCount() + getFooterViewsCount() + mInnerAdapter.getItemCount() + 1;
            } else {
                return getHeaderViewsCount() + getFooterViewsCount() + 1;
            }
        }
    
        @Override
        public int getItemViewType(int position) {
            int adjPosition = position - (getHeaderViewsCount() + 1);
            if (isRefreshHeader(position)) {
                return TYPE_REFRESH_HEADER;
            }
            if (isHeader(position)) {
                position = position - 1;
                return mHeaderTypes.get(position);
            }
            if (isFooter(position)) {
                return TYPE_FOOTER_VIEW;
            }
            int adapterCount;
            if (mInnerAdapter != null) {
                adapterCount = mInnerAdapter.getItemCount();
                if (adjPosition < adapterCount) {
                    return mInnerAdapter.getItemViewType(adjPosition);
                }
            }
            return TYPE_NORMAL;
        }
    
        @Override
        public long getItemId(int position) {
            if (mInnerAdapter != null && position >= getHeaderViewsCount()) {
                int adjPosition = position - getHeaderViewsCount();
                int adapterCount = mInnerAdapter.getItemCount();
                if (adjPosition < adapterCount) {
                    return mInnerAdapter.getItemId(adjPosition);
                }
            }
            return -1;
        }
    
        @Override
        public void onAttachedToRecyclerView(RecyclerView recyclerView) {
            super.onAttachedToRecyclerView(recyclerView);
            RecyclerView.LayoutManager manager = recyclerView.getLayoutManager();
            if (manager instanceof GridLayoutManager) {
                final GridLayoutManager gridManager = ((GridLayoutManager) manager);
                gridManager.setSpanSizeLookup(new GridLayoutManager.SpanSizeLookup() {
                    @Override
                    public int getSpanSize(int position) {
                        return (isHeader(position) || isFooter(position) || isRefreshHeader(position))
                                ? gridManager.getSpanCount() : 1;
                    }
                });
            }
            mInnerAdapter.onAttachedToRecyclerView(recyclerView);
        }
    
        @Override
        public void onDetachedFromRecyclerView(RecyclerView recyclerView) {
            mInnerAdapter.onDetachedFromRecyclerView(recyclerView);
        }
    
        @Override
        public void onViewAttachedToWindow(RecyclerView.ViewHolder holder) {
            super.onViewAttachedToWindow(holder);
            ViewGroup.LayoutParams lp = holder.itemView.getLayoutParams();
            if (lp != null && lp instanceof StaggeredGridLayoutManager.LayoutParams) {
                if(isHeader(holder.getLayoutPosition()) ||isRefreshHeader(holder.getLayoutPosition()) || isFooter(holder.getLayoutPosition())) {
                    StaggeredGridLayoutManager.LayoutParams p = (StaggeredGridLayoutManager.LayoutParams) lp;
                    p.setFullSpan(true);
                }
            }
    
            mInnerAdapter.onViewAttachedToWindow(holder);
        }
    
        @Override
        public void onViewDetachedFromWindow(RecyclerView.ViewHolder holder) {
            mInnerAdapter.onViewDetachedFromWindow(holder);
        }
    
        @Override
        public void onViewRecycled(RecyclerView.ViewHolder holder) {
            mInnerAdapter.onViewRecycled(holder);
        }
    
    
        public static class ViewHolder extends RecyclerView.ViewHolder { 
            public ViewHolder(View itemView) {
                super(itemView);
            }
        }
    
        /** * * @param isCallback whether position is from callback interface * @param position * @return */
        public int getAdapterPosition(boolean isCallback, int position) {
            if(isCallback) {
                int adjPosition = position - (getHeaderViewsCount() + 1);
                int adapterCount = mInnerAdapter.getItemCount();
                if (adjPosition < adapterCount) {
                    return adjPosition;
                }
            }else {
                return  (position + getHeaderViewsCount()) + 1;
            }
    
            return -1;
        }
    
        public void setOnItemClickListener(OnItemClickListener itemClickListener)
        {
            this.mOnItemClickListener = itemClickListener;
        }
    
        public void setOnItemLongClickListener(OnItemLongClickListener itemLongClickListener)
        {
            this.mOnItemLongClickListener = itemLongClickListener;
        }
    
    }

## RecyclerView Cursor Adapter ##

原文链接：[http://android.jobbole.com/81947/][http_android.jobbole.com_81947]

在Android平台中，CursorAdapter是一个适配器，用来把Cursor对象的数据展示到ListView控件里。RecyclerView适配器的第二篇将解释如何自己构造一个简单可重用的Cursor适配器，以及如何在你的应用中使用它。第三篇文章中，我将展示一个CursorAdapter类的更高级版本。

（相比于Android CursorAdapter，本例中用到的Cursor，不包含名为“\_id”的列）

首先，我们创建一个抽象类RecyclerViewCursorAdapter，该类持有Cursor对象并实现一些RecyclerView.Adapter类需要的方法（例如getItemCount()）。

而且，我们的适配器类将定义一个新的方法叫做onBindViewHolder(RecyclerView.ViewHolder, Cursor)。所以，你不需要每次获取Cursor对象来将数据绑定到ViewHolder。

我们还增加了一些帮助方法，例如：

*  swapCursor(Cursor)：提供带数据集（dataset）的适配器。
 *  getItem(int)：获得Cursor对象，移动到正确的位置。
 *  getCursor()：获得Cursor对象。

import android.database.Cursor;
    import android.support.v7.widget.RecyclerView;
    
    public abstract class RecyclerViewCursorAdapter<VH extends RecyclerView.ViewHolder> extends RecyclerView.Adapter<VH> { 
        private Cursor cursor;
    
        public void swapCursor(final Cursor cursor)
        {
            this.cursor = cursor;
            this.notifyDataSetChanged();
        }
    
        @Override
        public int getItemCount()
        {
            return this.cursor != null
                    ? this.cursor.getCount()
                    : 0;
        }
    
        public Cursor getItem(final int position)
        {
            if (this.cursor != null && !this.cursor.isClosed())
            {
                this.cursor.moveToPosition(position);
            }
    
            return this.cursor;
        }
    
        public Cursor getCursor()
        {
            return this.cursor;
        }
    
        @Override
        public final void onBindViewHolder(final VH holder, final int position)
        {
            final Cursor cursor = this.getItem(position);
            this.onBindViewHolder(holder, cursor);
        }
    
        public abstract void onBindViewHolder(final VH holder, final Cursor cursor);
    }

实现这个抽象类并填充数据是相当简单的。

import android.content.Context;
    import android.database.Cursor;
    import android.support.v7.widget.RecyclerView;
    import android.view.LayoutInflater;
    import android.view.View;
    import android.view.ViewGroup;
    import android.widget.TextView;
    
    import butterknife.Bind;
    import butterknife.ButterKnife;
    
    public class SearchResultsCursorAdapter extends RecyclerViewCursorAdapter<SearchResultsCursorAdapter.SearchResultViewHolder> implements View.OnClickListener { 
        private final LayoutInflater layoutInflater;
        private OnItemClickListener onItemClickListener;
    
        public SearchResultsCursorAdapter(final Context context)
        {
            super();
    
            this.layoutInflater = LayoutInflater.from(context);
        }
    
        public void setOnItemClickListener(final OnItemClickListener onItemClickListener)
        {
            this.onItemClickListener = onItemClickListener;
        }
    
        @Override
        public SearchResultViewHolder onCreateViewHolder(final ViewGroup parent, final int viewType)
        {
            final View view = this.layoutInflater.inflate(R.layout.listitem_search, parent, false);
            view.setOnClickListener(this);
    
            return new SearchResultViewHolder(view);
        }
    
        @Override
        public void onBindViewHolder(final SearchResultViewHolder holder, final Cursor cursor)
        {
            holder.bindData(cursor);
        }
    
         /* * View.OnClickListener */
    
        @Override
        public void onClick(final View view)
        {
            if (this.onItemClickListener != null)
            {
                final RecyclerView recyclerView = (RecyclerView) view.getParent();
                final int position = recyclerView.getChildLayoutPosition(view);
                if (position != RecyclerView.NO_POSITION)
                {
                    final Cursor cursor = this.getItem(position);
                    this.onItemClickListener.onItemClicked(cursor);
                }
            }
        }
    
        public static class SearchResultViewHolder extends RecyclerView.ViewHolder { 
            @Bind(R.id.textview_name)
            TextView textViewName;
    
            public SearchResultViewHolder(final View itemView)
            {
                super(itemView);
                ButterKnife.bind(this, itemView);
            }
    
            public void bindData(final Cursor cursor)
            {
                final String name = cursor.getString(cursor.getColumnIndex("name"));
                this.textViewName.setText(name);
            }
        }
    
        public interface OnItemClickListener { 
            void onItemClicked(Cursor cursor);
        }
    }

Providing the adapter with data in your Activity / Fragment:

在Activity或Fragment中提供带数据的适配器：

import android.app.Activity;
    import android.app.LoaderManager;
    import android.content.CursorLoader;
    import android.content.Loader;
    import android.database.Cursor;
    import android.net.Uri;
    import android.os.Bundle;
    
    public class SearchActivity extends Activity implements LoaderManager.LoaderCallbacks<Cursor> { 
        private static final int LOADER_SEARCH_RESULTS = 1;
    
        private SearchResultsCursorAdapter adapter;
    
        @Override
        protected void onCreate(final Bundle savedInstanceState)
        {
            super.onCreate(savedInstanceState);
    
            // create adapter
            this.adapter = new SearchResultsCursorAdapter(this);
    
            // start loader
            this.getLoaderManager().restartLoader(LOADER_SEARCH_RESULTS, null, this);
        }
    
        @Override
        public Loader<Cursor> onCreateLoader(final int id, final Bundle args)
        {
            switch (id)
            {
                case LOADER_SEARCH_RESULTS:
    
                    final Uri uri = Uri.parse("content://some_uri");
                    return new CursorLoader(this, uri, null, null, null, null);
            }
    
            return null;
        }
    
        @Override
        public void onLoadFinished(final Loader<Cursor> loader, final Cursor data)
        {
            switch (loader.getId())
            {
                case LOADER_SEARCH_RESULTS:
    
                    this.adapter.swapCursor(data);
                    break;
            }
        }
    
        @Override
        public void onLoaderReset(final Loader<Cursor> loader)
        {
            switch (loader.getId())
            {
                case LOADER_SEARCH_RESULTS:
    
                    this.adapter.swapCursor(null);
                    break;
            }
        }
    }

![7cc829d3gw1ex8kkzgkloj20g90sgmz4.jpg][]

![Android视频教程][Android]

[Android _ _ListView GridView]: http://blog.csdn.net/lmj623565791/article/details/38902805/
[RecyclerView_Adapter _RecyclerView]: http://blog.csdn.net/lmj623565791/article/details/51118836/
[Android _RecyclerView_HeaderView_FooterView]: http://blog.csdn.net/lmj623565791/article/details/51854533
[Android LRecyclerView]: http://blog.csdn.net/jdsjlzx/article/details/51794220
[RecyclerView_Header]: http://blog.csdn.net/qibin0506/article/details/49716795
[http_android.jobbole.com_81947]: http://android.jobbole.com/81947/
[7cc829d3gw1ex8kkzgkloj20g90sgmz4.jpg]: /images/20220714/a84abc3e0d9244a6bee1914b8e60cd4c.png
[Android]: /images/20220714/6613e7cf42b540edbea209a79b6b64a2.png