RecyclerView 上拉加载的实现

落日映苍穹つ 2022-05-28 10:25 240阅读 0赞

先看效果图：  
![70][]

实现：

使用HeaderAndFooterRecyclerView添加Footer实现上拉加载。

1.compile

compile  'com.takwolf.android:hf-recyclerview:0.1.1'

2.使用

使用方法与RecylerView 相同，只是多了两个方法：addHeader /addFooter。

xml

<?xml version="1.0" encoding="utf-8"?>
    <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent" android:background="@color/com_bg_gray_eeeeee" android:orientation="vertical">
    
        <com.takwolf.android.hfrecyclerview.HeaderAndFooterRecyclerView android:id="@+id/acty_allproduct_rv" android:layout_width="match_parent" android:layout_height="wrap_content" />
    </LinearLayout>

java

rv = (HeaderAndFooterRecyclerView) findViewById(R.id.acty_allproduct_rv);
         rv.setLayoutManager(new LinearLayoutManager(this)); 
         adapter = new AllProductAdapter(AllProductActivity.this, list);
         rv.setAdapter(adapter);
         rv.addOnScrollListener(new LoadMore.ForRecyclerView(AllProductActivity.this));

LoadMore

辅助类，实现滑动到底部，回调OnScrollListentrer接口中的方法

public class LoadMore { 
    
        private LoadMore(){
    
        }
    
    
        public static  class ForRecyclerView extends RecyclerView.OnScrollListener{ 
    
    
            private  int mLastVisiblePostion=-1;
    
            private OnLoadMoreListener loadMoreListener;
    
            public ForRecyclerView(OnLoadMoreListener loadMoreListener) {
                this.loadMoreListener = loadMoreListener;
            }
    
    
            @Override
            public void onScrollStateChanged(RecyclerView recyclerView, int newState) {
                super.onScrollStateChanged(recyclerView, newState);
    
                View firstView  =recyclerView.getChildAt(0);
    
    
                int top=firstView.getTop();
                int  topEdge=recyclerView.getPaddingTop();
                //判断RecyclerView 的itemView是否满屏,如果不满上啦不会触发加载更多
    
                boolean isFullScreen=top<topEdge;
    
                RecyclerView.LayoutManager manager=recyclerView.getLayoutManager();
                int itemCount=manager.getItemCount();
    
    
                if (newState==RecyclerView.SCROLL_STATE_IDLE&&mLastVisiblePostion==(itemCount-1)&&isFullScreen){
                    //最后一个item的时候,显示加载更多,
                    //添加LoadMore布局
    
                    loadMoreListener.showLoadMore();
    
                    loadMoreListener.onLoadMore();
                }
    
    
            }
    
            @Override
            public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
                super.onScrolled(recyclerView, dx, dy);
    
                RecyclerView.LayoutManager layoutManager = recyclerView.getLayoutManager();
                if (layoutManager instanceof LinearLayoutManager) {
                    mLastVisiblePostion = ((LinearLayoutManager) layoutManager).findLastVisibleItemPosition();
                } else if (layoutManager instanceof GridLayoutManager) {
                    mLastVisiblePostion = ((GridLayoutManager) layoutManager).findLastVisibleItemPosition();
                } else if (layoutManager instanceof StaggeredGridLayoutManager) {
                    StaggeredGridLayoutManager staggeredGridLayoutManager = (StaggeredGridLayoutManager) layoutManager;
                    int[] lastPositions = new int[staggeredGridLayoutManager.getSpanCount()];
                    staggeredGridLayoutManager.findLastVisibleItemPositions(lastPositions);
                    mLastVisiblePostion = findMax(lastPositions);
                }
            }
        }
    
    
    
        public interface OnLoadMoreListener { 
            void showLoadMore();
    
            void onLoadMore();
    
            void hideLoadMore();
        }
    
    
    
    
        /** * 获取数组中的最大值 * * @param lastPositions * @return */
        protected  static int findMax(int[] lastPositions) {
            int max = lastPositions[0];
            for (int value : lastPositions) {
                if (value > max) {
                    max = value;
                }
            }
            return max;
        }
    
    }

Activity全部代码

public class AllProductActivity extends DrawerBaseActivity implements LoadMore.OnLoadMoreListener { 
    
        private HeaderAndFooterRecyclerView rv;
    
        private List<ProductData.BankProductBean> list;
    
    
        private AllProductAdapter adapter;
    
        private View load_more;
    
        private boolean loadMore=false;
    
        private boolean loadMoreFinish=true;
    
        @Override
        protected int getLayoutId() {
            return R.layout.activity_allproduct;
        }
    
        @Override
        protected void initView() {
    
            rv = (HeaderAndFooterRecyclerView) findViewById(R.id.acty_allproduct_rv);
            rv.setLayoutManager(new LinearLayoutManager(this));
            load_more = LayoutInflater.from(this).inflate(R.layout.load_more, null);
    
            //给控件设置弹性效果
            OverScrollDecoratorHelper.setUpOverScroll(rv, OverScrollDecoratorHelper.ORIENTATION_VERTICAL);
    
        }
    
        @Override
        public void initData() {
    
    
            list = new ArrayList<>();
            QpRetrofitManager.getInstance().getProductAll().subscribe(new BaseObServer<ProductData>() {
                @Override
                public void onHandleSuccess(ProductData productData) {
    
    
                    if (Util.isNull(productData)||Util.isNull(productData.getBankProduct())||productData.getBankProduct().size()==0){
    
                    }else {
                        list.addAll(productData.getBankProduct());
                        list.addAll(productData.getBankProduct());
                        list.addAll(productData.getBankProduct());
                        list.addAll(productData.getBankProduct());
                        list.addAll(productData.getBankProduct());
                        list.addAll(productData.getBankProduct());
                        list.addAll(productData.getBankProduct());
                        list.addAll(productData.getBankProduct());
                        list.addAll(productData.getBankProduct());
                        list.addAll(productData.getBankProduct());
                        list.addAll(productData.getBankProduct());
                        list.addAll(productData.getBankProduct());
                        list.addAll(productData.getBankProduct());
                        list.addAll(productData.getBankProduct());
                        list.addAll(productData.getBankProduct());
    
                        adapter = new AllProductAdapter(AllProductActivity.this, list);
                        rv.setAdapter(adapter);
    
                        rv.addOnScrollListener(new LoadMore.ForRecyclerView(AllProductActivity.this));
                    }
                }
            });
    
    
        }
    
        @Override
        protected void initListener() {
            //让RecyclerView 有弹性效果
    
    // OverScrollDecoratorHelper.setUpOverScroll(rv, OverScrollDecoratorHelper.ORIENTATION_VERTICAL);
    
        }
    
    
        public static void actionStart(Context context) {
            Intent intent = new Intent(context, AllProductActivity.class);
    
            context.startActivity(intent);
        }
    
        @Override
        public void showLoadMore() {
    
            LogUtils.e("显示加载更多");
            ViewGroup parent = (ViewGroup) load_more.getParent();
            if (parent != null) {
                parent.removeView(load_more);
            }
            rv.addFooterView(load_more);
            ViewGroup.LayoutParams params = load_more.getLayoutParams();
            params.width = ViewGroup.LayoutParams.MATCH_PARENT;
            params.height = ViewGroup.LayoutParams.MATCH_PARENT;
            load_more.setLayoutParams(params);
        }
    
        @Override
        public void onLoadMore() {
    
            LogUtils.e("加载更多");
            if (!loadMoreFinish) return;
            if (isLoadMore()){
                //不显示加载更多
                hideLoadMore();
            }else {
    
                //判读是否剩下的为0
                if (Util.isNull(list) || list.size() == 0) {
    
                    rv.postDelayed(new Runnable() {
                        @Override
                        public void run() {
                            hideLoadMore();
                            //没有更多了布局
    // setNoMoreView();
                            loadMore = false;
                            loadMoreFinish = true;
                        }
                    }, 2000);
    
                } else if (list.size() < 10) {
                    rv.postDelayed(new Runnable() {
                        @Override
                        public void run() {
                            hideLoadMore();
                            //上拉加载添加评论
                            adapter.addReplyListAndNotify(list);
                            //没有更多了布局
    // setNoMoreView();
                            loadMore = false;
                            loadMoreFinish = true;
                        }
                    }, 2000);
                } else {
                    rv.postDelayed(new Runnable() {
                        @Override
                        public void run() {
                            hideLoadMore();
                            //上拉加载添加评论
                            adapter.addReplyListAndNotify(list);
                            loadMoreFinish = true;
                        }
                    }, 2000);
                }
    
            }
    
        }
    
        @Override
        public void hideLoadMore() {
            rv.removeFooterView(load_more);
        }
    
        public boolean isLoadMore() {
            return loadMore;
        }
    }

[Demo 地址][Demo]

以上便可以实现上拉加载的效果，上拉加载布局可以自定义。

[70]: /images/20220528/8a244de27575446c963ccb7d61184f90.png
[Demo]: https://github.com/Kenway090704/QProj