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    【已解决】ReactJS中如何实现上拉加载更多数据

    ReactJS crifan 5011浏览 0评论

    之前已经实现了：

    首次进页面后，加载列表，但是只是加载了1页（10条）数据：

      searchCowListByList(start = 1) {
        const url = `/cow/cow/search/list?start=${start}&limit=10`;
        this.props.fetch(url, {}, ( data ) => {
          console.log(data);
          const { cowList } = this.state;
          this.setState({
            cowList: start === 1 ? data : cowList.concat(data)
          });
        });
      }

    页面：

    reactjs scroll up load more page

    javascript – Infinite scrolling with React JS – Stack Overflow

    seatgeek/react-infinite: A browser-ready efficient scrolling container based on UITableView

    CassetteRocks/react-infinite-scroller: ⏬ Infinite scroll component for React in ES6

    RealScout/redux-infinite-scroll: React infinite scroll component designed for a Redux data-flow.

    brigade/react-waypoint: A React component to execute a function whenever you scroll to an element.

    先去试试：

    CassetteRocks/react-infinite-scroller: ⏬ Infinite scroll component for React in ES6

    ➜  ucowsapp git:(master) ✗ npm install react-infinite-scroller –save
    npm WARN [email protected] No repository field.
    npm WARN [email protected] No license field.
    added 1 package and removed 3 packages in 12.154s

    然后用代码：

    import InfiniteScroll from ‘react-infinite-scroller’;
    @connect(reducer, bindActions(actions))
    export default class CowManagement extends Component {
      state = {
        cowList: [],
        curPageNum : 1,
        hasMore : true
      };
      constructor(props) {
        super(props);
        autoBind(this);
        this.searchKeyword = "";
        // this.delayedLoadMore = _.debounce(this.searchCowListByList, 200);
        this.searchCowListByList();
      }
      searchCowListByList() {
        console.log(`searchCowListByList: this.state.curPageNum=${this.state.curPageNum},nextPageNum=${nextPageNum}`);
        let nextPageNum = this.state.curPageNum + 1;
        console.log(`nextPageNum=${nextPageNum}`);
        this.setState({ curPageNum : nextPageNum});
        const url = `/cow/cow/search/list?start=${this.state.curPageNum}&limit=10`;
        this.props.fetch(url, {}, ( data ) => {
          console.log(data);
          console.log(typeof(data));
          console.log(data.length);
          //if (data === []) {
          if (data.length === 0) {
            this.setState({hasMore : false});
          }
          console.log(`this.state.hasMore=${this.state.hasMore}`);
          const { cowList } = this.state;
          this.setState({
            cowList: this.state.curPageNum === 1 ? data : cowList.concat(data)
            // cowList: data
          });
        });
      }
      loadMore(){
        console.log("loadMore");
        //setTimeout(this.searchCowListByList, 200);
        this.searchCowListByList();
      }
      render() {
        const { cowList } = this.state;
        const { reproductiveStateTypeDict } = this.props;
        // console.log(cowList);
        return (
          <div class={style.the_herd_all}>
            <Search
              placeholder="请输入牛号搜索"
              onInputChange={this.onInputChange}
            />
            <div class={style.the_herd_all}>
              <ul class={style.nn_a_list}>
                      {/* useWindow={false}
                      threshold={250}
                      element={"a"}
                      initialLoad={false} */}
                <div style="height:600px;overflow:auto;">
                  <InfiniteScroll
                      pageStart={0}
                      loadMore={this.loadMore}
                      hasMore={this.state.hasMore}
                      loader={<div className="loader">正在加载 …</div>}
                  >
                  {
                    cowList.map(item => {
                      return (
                        <CowListItem data={item} reproductiveStateTypeDict={reproductiveStateTypeDict} />
                      );
                    })
                  }
                  </InfiniteScroll>
                </div>
              </ul>
            </div>
          </div>
        );
      }
    }

    但是郁闷的是：

    结果是，进入页面后，还没有上拉，就加载完毕所有的页面了：

    调试了半天，始终无法实现：

    首次进入页面，显示第一页

    然后上拉滚动页面到底部时，再去加载第二页，直到无法加载为止。

    换用：

    RealScout/redux-infinite-scroll: React infinite scroll component designed for a Redux data-flow.

    ➜  ucowsapp git:(master) ✗ npm install redux-infinite-scroll –save
    npm WARN [email protected] No repository field.
    npm WARN [email protected] No license field.
    added 1 package in 11.919s

    然后代码改为，类似的写法：

      loadMore(){
        console.log("loadMore");
        //setTimeout(this.searchCowListByList, 200);
        this.searchCowListByList();
      }
      renderItemList(){
        return (
          this.state.cowList.map(item => {
            return (
              <CowListItem data={item} reproductiveStateTypeDict={this.props.reproductiveStateTypeDict} />
            );
          })
        );
      }
      render() {
        // const { cowList } = this.state;
        // const { reproductiveStateTypeDict } = this.props;
        // console.log(cowList);
        return (
          <div class={style.the_herd_all}>
            <Search
              placeholder="请输入牛号搜索"
              onInputChange={this.onInputChange}
            />
            <div class={style.the_herd_all}>
              <ul class={style.nn_a_list}>
                      {/* useWindow={false}
                      threshold={250}
                      element={"a"}
                      initialLoad={false} */}
                 {/* <div style="height:600px;overflow:auto;">
                  <InfiniteScroll
                      pageStart={0}
                      loadMore={this.loadMore}
                      hasMore={this.state.hasMore}
                      loader={<div className="loader">正在加载 …</div>}
                  >
                  </InfiniteScroll>
                </div> */}
                  {/* {
                    cowList.map(item => {
                      return (
                        <CowListItem data={item} reproductiveStateTypeDict={reproductiveStateTypeDict} />
                      );
                    })
                  } */}
                <InfiniteScroll
                  hasMore={this.state.hasMore}
                  children={this.renderItemList()}
                  loadMore={this.loadMore}
                  showLoader={true}
                />
              </ul>
            </div>
          </div>
        );
      }
    }

    结果问题依旧：

    首次进去，就加载完毕所有的数据了。。。

    再去试试：

    seatgeek/react-infinite: A browser-ready efficient scrolling container based on UITableView

    ➜  ucowsapp git:(master) ✗ npm install react-infinite –save
    npm WARN [email protected] No repository field.
    npm WARN [email protected] No license field.
    added 3 packages in 12.187s

    结果代码写好了：

      loadMore(){
        console.log("loadMore");
        this.setState({ isInfiniteLoading: true });
        //setTimeout(this.searchCowListByList, 200);
        this.searchCowListByList();
      }
      renderItemList(){
        return (
          this.state.cowList.map(item => {
            return (
              <CowListItem data={item} reproductiveStateTypeDict={this.props.reproductiveStateTypeDict} />
            );
          })
        );
      }
      elementInfiniteLoad() {
        return <div className="infinite-list-item">
          Loading…
        </div>;
      }
                <Infinite
                  elementHeight={40}
                  containerHeight={550}
                  infiniteLoadBeginEdgeOffset={200}
                  onInfiniteLoad={this.loadMore}
                  loadingSpinnerDelegate={this.elementInfiniteLoad}
                  isInfiniteLoading={this.state.isInfiniteLoading}
                >
                  {this.renderItemList()}
                </Infinite>

    调用库时，库出错了：

    reactjs scroll up bottom load more

    react js scroll up bottom load more

    react js scroll bottom load more

    react-infinite-scroller not work

    React infinite scrolling：reactjs

    brillout/awesome-react-components: Catalog of React Components & Libraries

    nmn/react-infinity: A UITableView Inspired list and grid display solution with element culling and smooth animations

    后来去看库：

    CassetteRocks/react-infinite-scroller: ⏬ Infinite scroll component for React in ES6

    的源码，发现在InfiniteScroll下面是一个div的list：

    而不是我此处的所有的item的列表平铺出来的。

    结果代码改为：

            <div class={style.the_herd_all}>
              <InfiniteScroll
                  pageStart={this.state.curPageNum}
                  loadMore={this.loadMore}
                  hasMore={this.state.hasMore}
                  loader={<div className="loader">正在加载 …</div>}
              >
                <ul class={style.nn_a_list}>
                  <div>
                    {
                      this.state.cowList.map(item => {
                        return (
                          <CowListItem data={item} reproductiveStateTypeDict={this.props.reproductiveStateTypeDict} />
                        );
                      })
                    }
                  </div>
                </ul>
              </InfiniteScroll>
            </div>

    问题依旧。

    此处，把其源码粘贴到项目中，然后稍作改动未Preact的代码。期间遇到：

    【已解决】如何把React.createElement转换为preact的语法

    然后，去调试，发现个诡异的事情：

    第一次加载时，滚动的高度就有22了：

    el.scrollHeight=22,el.parentNode.scrollTop=0,el.parentNode.clientHeight=22 -> offset=0

    更诡异的是：

    在用户没有滚动时，始终继续触发，滚动高度低于thedshold阈值，所以始终继续调用loadMore了：

    这部分的log是：

    即，在第一次initialLoad=true

    el.scrollHeight=22,el.parentNode.scrollTop=0,el.parentNode.clientHeight=22 -> offset=0
    InfiniteScroll.js?9381:137 offset < Number(this.props.threshold)=true

    加载调用loadMore: pageNum=1后，

    还是：

    el.scrollHeight=22,el.parentNode.scrollTop=0,el.parentNode.clientHeight=22 -> offset=0
    InfiniteScroll.js?9381:137 offset < Number(this.props.threshold)=true

    所以导致无限循环下去调用loadMore去加载所有数据了。

    所以问题就是要找到：

    为何每次都是：

    滚动高度el.scrollHeight为22？不应该是0吗？

    另外，每次都是：

    el.parentNode.scrollTop=0

    el.parentNode.clientHeight=22

    所以导致：

    offset=0

    react scrollHeight

    react scrollHeight parentNode.clientHeight

    有人遇到类似问题：

    loading forever without stopping on safari mobile · Issue #26 · CassetteRocks/react-infinite-scroller

    那scrollHeight改回offsetHeight去试试：

          // offset = el.scrollHeight – el.parentNode.scrollTop – el.parentNode.clientHeight;
          offset = el.offsetHeight – el.parentNode.scrollTop – el.parentNode.clientHeight;
          console.log(`el.scrollHeight=${el.scrollHeight},el.offsetHeight=${el.offsetHeight}，el.parentNode.scrollTop=${el.parentNode.scrollTop},el.parentNode.clientHeight=${el.parentNode.clientHeight} -> offset=${offset}`);

    结果问题依旧：

    el.scrollHeight=22,el.offsetHeight=22，el.parentNode.scrollTop=0,el.parentNode.clientHeight=22 -> offset=0
    InfiniteScroll.js?9381:138 offset < Number(this.props.threshold)=true

    scrollHeight和offsetHeight都是22，且一直没变，还是一直加载。

    Dom scroll parent with unfixed height · Issue #51 · CassetteRocks/react-infinite-scroller

    抽空去看看，是否需要使用这个：

    digidem/react-dimensions: React higher-order component to get dimensions of container

    再试试parentNode.scrollHeight：

          // offset = el.scrollHeight – el.parentNode.scrollTop – el.parentNode.clientHeight;
          // offset = el.offsetHeight – el.parentNode.scrollTop – el.parentNode.clientHeight;
          offset = el.parentNode.scrollHeight – el.parentNode.scrollTop – el.parentNode.clientHeight;
          console.log(`el.scrollHeight=${el.scrollHeight},el.offsetHeight=${el.offsetHeight},el.parentNode.scrollHeight=${el.parentNode.scrollHeight},el.parentNode.scrollTop=${el.parentNode.scrollTop},el.parentNode.clientHeight=${el.parentNode.clientHeight} -> offset=${offset}`);

    结果问题依旧：

    el.scrollHeight=22,el.offsetHeight=22,el.parentNode.scrollHeight=22,el.parentNode.scrollTop=0,el.parentNode.clientHeight=22 -> offset=0
    InfiniteScroll.js?9381:139 offset < Number(this.props.threshold)=true

    然后去调试，修改了每行row的高度为90，结果log出来的滚动高度还是22

    element clientHeight offsetHeight scrollHeight 22

    把：

      renderItemList(){
        return (
          this.state.cowList.map(item => {
            return (
              <CowListItem data={item} reproductiveStateTypeDict={this.state.reproductiveStateTypeDict} />
            );
          })
        );
      }

    改为：

        let itemList = [];
        this.state.cowList.map((item) => {
          itemList.push(
            <CowListItem data={item} reproductiveStateTypeDict={this.state.reproductiveStateTypeDict} />
          );
        });
        console.log(itemList);

    结果问题依旧。

    【已解决】ReactJS中如何判断页面滚动到底部以实现下拉加载更多页面数据

    转载请注明：在路上 » 【已解决】ReactJS中如何实现上拉加载更多数据

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