RecyclerView与SwipeRefreshLayout的完美搭配

待我称王封你为后i 2021-09-22 05:10 353阅读 0赞

SwipeRefreshLayout 是谷歌公司推出的用于下拉刷新的控件，在Version 19.1之后SwipeRefreshLayout 被放到support v4中。我们在前面也已经说过一个SwipeRefreshLayout和ListView实现上拉加载、下拉刷新的例子。而现在RecyclerView也已作为实现列表功能的首选组件，而它本身并没有实现上拉加载、下拉刷新的功能，本节我们就来利用SwipeRefreshLayout 和RecyclerView来实现上拉加载、下拉刷新的功能。

SwipeRefreshLayout 常用的方法如下:

*  setOnRefreshListener(OnRefreshListener):下拉刷新监听器，当用户下拉的时候会触发
 *  setRefreshing(boolean):设置SwipeRefreshLayout当前是否处于刷新状态，一般是在请求数据的时候设置为true，在数据被加载到View中后，设置为false。
 *  isRefreshing():检查是否处于刷新状态
 *  setColorSchemeResources():设置进度条的颜色主题，最多设置四种，以前的setColorScheme()方法已经弃用了。
 *  setProgressViewOffset(boolean scale, int start, int end) 调整进度条距离屏幕顶部的距离

布局文件很简单

<?xml version="1.0" encoding="utf-8"?>
    <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:tools="http://schemas.android.com/tools"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:paddingBottom="@dimen/activity_vertical_margin"
        android:paddingLeft="@dimen/activity_horizontal_margin"
        android:paddingRight="@dimen/activity_horizontal_margin"
        android:paddingTop="@dimen/activity_vertical_margin"
        tools:context="com.xmr.recycleandswiperefresh.MainActivity">
    
        <android.support.v4.widget.SwipeRefreshLayout
            android:id="@+id/srl_main"
            android:layout_width="match_parent"
            android:layout_height="match_parent">
    
            <android.support.v7.widget.RecyclerView
                android:id="@+id/ryv_main"
                android:layout_width="match_parent"
                android:layout_height="match_parent" />
    
        </android.support.v4.widget.SwipeRefreshLayout>
    </RelativeLayout>

接着在Activity中获取SwipeRefreshLayout控件并且设置OnRefreshListener监听器，同时实现里边的onRefresh()方法，在该方法中进行网络请求最新数据，然后刷新RecyclerView列表同时设置SwipeRefreshLayout的显示效果。具体代码如下：

mSwipeRefreshLayout.setOnRefreshListener(new SwipeRefreshLayout.OnRefreshListener() {
        @Override
        public void onRefresh() {
            //实际项目中这里一般是用网络请求获取数据
            mList.add("下拉刷新");
            mAdapter.notifyDataSetChanged();
            mSwipeRefreshLayout.setRefreshing(false);
        }
    });

RecyclerView的实现：  
第一种，下拉刷新和上拉刷新都用SwipeRefreshLayout 自带的效果

mRecyclerView.setOnScrollListener(new RecyclerView.OnScrollListener() {
    
                @Override
                public void onScrollStateChanged(RecyclerView recyclerView,
                                                 int newState) {
                    super.onScrollStateChanged(recyclerView, newState);
                    if (newState == RecyclerView.SCROLL_STATE_IDLE
                            && lastVisibleItem + 1 == mAdapter.getItemCount()) {
                        mSwipeRefreshLayout.setRefreshing(true);
                        //实际项目中这里一般是用网络请求获取数据
                        mList.add("上拉加载");
                        //为了有刷新的效果，延迟关闭刷新效果
                        mSwipeRefreshLayout.postDelayed(new Runnable() {
                            @Override
                            public void run() {
                                mSwipeRefreshLayout.setRefreshing(false);
                                mAdapter.notifyDataSetChanged();
    
                            }
                        }, 2000);
    
                    }
                }
    
                @Override
                public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
                    super.onScrolled(recyclerView, dx, dy);
                    //判断是当前layoutManager是否为LinearLayoutManager
                    // 只有LinearLayoutManager才有查找第一个和最后一个可见view位置的方法
                    if (linearLayoutManager instanceof LinearLayoutManager) {
                        //获取最后一个可见view的位置
                        lastVisibleItem = linearLayoutManager.findLastVisibleItemPosition();
                        //获取第一个可见view的位置
    //            int firstItemPosition = linearLayoutManager.findFirstVisibleItemPosition();
                    }
                }
            });

效果如下：

![Center][]

第二种实现下拉刷新用SwipeRefreshLayout 自带的效果， 上拉加载我们可以给RecyclerView 添加一个类似FooterView的item。  
我们在Adapter中实现：

package com.xmr.recycleandswiperefresh;
    
    import android.content.Context;
    import android.support.v7.widget.RecyclerView;
    import android.view.LayoutInflater;
    import android.view.View;
    import android.view.ViewGroup;
    import android.widget.LinearLayout;
    import android.widget.TextView;
    
    import java.util.List;
    
    /**
     * Created by Administrator on 2016/9/13.
     */
    public class RefreshAdapter1 extends RecyclerView.Adapter<RecyclerView.ViewHolder> {
        private Context mContext;
        private List<String> mDatas;
        private static final int TYPE_ITEM = 0;  //普通Item View
    
        private static final int TYPE_FOOTER = 1;  //底部FootView
        //已经到底了
        public static final int PULLUP_LOAD_MORE = 0;
        //正在加载中
        public static final int LOADING_MORE = 1;
        //上拉加载状态-默认为0
        private int load_more_status = 0;
    
        public RefreshAdapter1(Context mContext, List<String> mDatas) {
            this.mContext = mContext;
            this.mDatas = mDatas;
        }
    
        @Override
        public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
            //进行判断显示类型，来创建返回不同的View
            if (viewType == TYPE_ITEM) {
                View view = LayoutInflater.from(parent.getContext()).inflate(
                        R.layout.item_recycler_refresh, null);
    //            view.setLayoutParams(new LayoutParams(LayoutParams.MATCH_PARENT,
    //                    LayoutParams.WRAP_CONTENT));
                return new ItemHolder(view);
            }
            // type == TYPE_FOOTER 返回footerView
            else if (viewType == TYPE_FOOTER) {
                View view = LayoutInflater.from(parent.getContext()).inflate(
                        R.layout.item_recycler_footer, null);
    //            view.setLayoutParams(new LayoutParams(LayoutParams.MATCH_PARENT,
    //                    LayoutParams.WRAP_CONTENT));
                return new FooterHolder(view);
            }
            return null;
        }
    
        @Override
        public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {
            if (holder instanceof ItemHolder) {
                ItemHolder itemHolder = (ItemHolder) holder;
                itemHolder.textView.setText(mDatas.get(position));
            } else if (holder instanceof FooterHolder) {
                FooterHolder footHolder = (FooterHolder) holder;
                //这句如果不注释，那么底部就会有添加的一个item
                footHolder.linearLayout.setVisibility(View.GONE);
                switch (load_more_status) {
                    case PULLUP_LOAD_MORE:
                        footHolder.linearLayout.setVisibility(View.GONE);
    //                    footHolder.textView.setText("已经到底了");
                        break;
                    case LOADING_MORE:
                        footHolder.linearLayout.setVisibility(View.VISIBLE);
                        footHolder.textView.setText("正在加载更多数据...");
                        break;
                }
            }
        }
    
        @Override
        public int getItemCount() {
            return mDatas == null ? 0 : mDatas.size() + 1;
        }
    
        @Override
        public int getItemViewType(int position) {
            // 最后一个item设置为footerView
            if (position + 1 == getItemCount()) {
                return TYPE_FOOTER;
            } else {
                return TYPE_ITEM;
            }
        }
    
        class ItemHolder extends RecyclerView.ViewHolder {
            public TextView textView;
    
            public ItemHolder(View itemView) {
                super(itemView);
                textView = (TextView) itemView.findViewById(R.id.tv_item_recycler_refresh);
            }
        }
    
        class FooterHolder extends RecyclerView.ViewHolder {
            public TextView textView;
            public LinearLayout linearLayout;
    
            public FooterHolder(View itemView) {
                super(itemView);
                textView = (TextView) itemView.findViewById(R.id.tv_item_recycler_footer);
                linearLayout = (LinearLayout) itemView.findViewById(R.id.ll_item_recycler_footer);
            }
        }
    
        /**
         * //上拉加载更多
         * PULLUP_LOAD_MORE=0;
         * //正在加载中
         * LOADING_MORE=1;
         * //加载完成已经没有更多数据了
         * NO_MORE_DATA=2;
         *
         * @param status
         */
        public void changeMoreStatus(int status) {
            load_more_status = status;
            notifyDataSetChanged();
        }
    }

而对RecyclerView的上拉加载，我们这样实现：

mRecyclerView.setOnScrollListener(new RecyclerView.OnScrollListener() {
    
                @Override
                public void onScrollStateChanged(RecyclerView recyclerView,
                                                 int newState) {
                    super.onScrollStateChanged(recyclerView, newState);
                    if (newState == RecyclerView.SCROLL_STATE_IDLE
                            && lastVisibleItem + 1 == mAdapter.getItemCount()) {
                        Log.i(">>>>>", ">>>>" + lastVisibleItem + ">>>" + mAdapter.getItemCount());
                        mAdapter.changeMoreStatus(mAdapter.LOADING_MORE);
                        //为了有刷新的效果，延迟2s修改状态
                        new Handler().postDelayed(new Runnable() {
                            @Override
                            public void run() {
                                mAdapter.changeMoreStatus(RefreshAdapter1.PULLUP_LOAD_MORE);
                                //实际项目中这里一般是用网络请求获取数据
                                mList.add("上拉加载");
                            }
                        }, 2000);
                    }
                }
    
                @Override
                public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
                    super.onScrolled(recyclerView, dx, dy);
                    //判断是当前layoutManager是否为LinearLayoutManager
                    // 只有LinearLayoutManager才有查找第一个和最后一个可见view位置的方法
                    if (linearLayoutManager instanceof LinearLayoutManager) {
                        //获取最后一个可见view的位置
                        lastVisibleItem = linearLayoutManager.findLastVisibleItemPosition();
                        //获取第一个可见view的位置
    //            int firstItemPosition = linearLayoutManager.findFirstVisibleItemPosition();
                    }
                }
            });
        }

最终效果如下：

![Center 1][]

不过，现在也有点bug，如果列表没有占满屏幕的话，下拉刷新的时候也会同时触发上拉加载的效果，大家如果有好的解决方案的话可以给我说下，先谢谢了   
参考：

[http://blog.csdn.net/dalancon/article/details/46125667][http_blog.csdn.net_dalancon_article_details_46125667]

[http://www.cnblogs.com/xiaoyaoxia/p/4977125.html][http_www.cnblogs.com_xiaoyaoxia_p_4977125.html]

[http://blog.csdn.net/developer\_jiangqq/article/details/49992269][http_blog.csdn.net_developer_jiangqq_article_details_49992269]

[http://blog.csdn.net/salute\_li/article/details/52118504][http_blog.csdn.net_salute_li_article_details_52118504]

[http://www.cnblogs.com/csonezp/p/5050324.html][http_www.cnblogs.com_csonezp_p_5050324.html]

[Center]: /images/20210920/e625c1658aeb4bfd9b2ccd784e22bcc2.png
[Center 1]: /images/20210920/0da9d0d79b2f40448654b916487d32dd.png
[http_blog.csdn.net_dalancon_article_details_46125667]: http://blog.csdn.net/dalancon/article/details/46125667
[http_www.cnblogs.com_xiaoyaoxia_p_4977125.html]: http://www.cnblogs.com/xiaoyaoxia/p/4977125.html
[http_blog.csdn.net_developer_jiangqq_article_details_49992269]: http://blog.csdn.net/developer_jiangqq/article/details/49992269
[http_blog.csdn.net_salute_li_article_details_52118504]: http://blog.csdn.net/salute_li/article/details/52118504
[http_www.cnblogs.com_csonezp_p_5050324.html]: http://www.cnblogs.com/csonezp/p/5050324.html