[FlatList] Some questions about onEndReached

[sunhailongisme]

         <FlatList
                        keyboardShouldPersistTaps={'handled'}
                        data={this.state.listData}
                        initialNumToRender={this.initialNumToRender}
                        keyExtractor={this._keyExtractor}
                        renderItem={this.getView}//渲染每一条记录
                         ListEmptyComponent={this.emptyComponent}
                        ListFooterComponent={this.footer}//尾部
                        //下拉刷新，必须设置refreshing状态
                        onRefresh={this.onRefresh}
                        refreshing={this.state.refreshing}
                        //上拉加载
                        onEndReachedThreshold={0.1}
                        onEndReached={this.onEndReached}
                    >
         </FlatList>


onEndReached  =() => {
    currentPage++;
    if (this.state.showFoot === 0){
      this.setState({refreshing:false});
    }
    params.reqParams.page = currentPage;
    if (this.state.data.totalpage&&this.state.data.totalpage !== undefined){
      if(currentPage == this.state.data.totalpage){
        this.setState({showFoot:1});//底部显示没有更多数据
      }else if(currentPage>this.state.data.totalpage){
        return
      }
    }
    Fetch.fetchData('jsonpost',{},(res) => {
      if (res.success!==undefined&&res.success === false){
        this.setState({msg:'连接超时,请重试！'});
        this.alertSearch._show();
      }
      if (res.respCode === 'success'){
        this.setState({
          listData:this.state.listData.concat(res.data.ENTERPRISES),
          showFoot:0,
          refreshing:false,
          totalnum:res.totalnum,
        });
      }else if(res.respCode === 'failed'){
        this.setState({msg:res.Errmsg,refreshing:false});
        this.alertSearch._show();
      }
    })
};

onEndReached triggered 2 times on ios ，but，it is normal on android .If I change a way of writing:

onEndReached  =() => {
    currentPage++;
    if (this.state.showFoot === 0){
      this.setState({refreshing:false});
    }
    params.reqParams.page = currentPage;
    if (this.state.data.totalpage&&this.state.data.totalpage !== undefined){
      if(currentPage == this.state.data.totalpage){
        this.setState({showFoot:1});//底部显示没有更多数据
      }else if(currentPage>this.state.data.totalpage){
        return
      }
    }
    Fetch.fetchData('jsonpost',{},(res) => {
      if (res.success!==undefined&&res.success === false){
        this.setState({msg:'连接超时,请重试！'});
        this.alertSearch._show();
      }
      if (res.respCode === 'success'){
       const getNewData = (res) =>{
         let oldData = this.state.listData;
         for (let i = 0;i<res.data.ENTERPRISES.length;i++){
          oldData.push(res.data.ENTERPRISES[i]);
         }
          return oldData 
        }
        const newData = getNewData(res);
        this.setState({
          listData:newData,
          showFoot:0,
          refreshing:false,
          totalnum:res.totalnum,
        });
      }else if(res.respCode === 'failed'){
        this.setState({msg:res.Errmsg,refreshing:false});
        this.alertSearch._show();
      }
    })
};

The method of "onEndReached" on IOS will not be executed two times.But there will be another problem，
When I first scrolled to the bottom of the list to trigger the "onEndReached" method, if the network request failed and no new list data was rendered, I scrolled again to the bottom of the list and the "onEndReached" method could not be triggered again

The problems of the above two ways of writing：

1、When I am not on the first page list, if I afresh render the list, It will still automatically execute a "onEndReached" method, but I do not scroll to trigger the "onEndReached" method 。
2、When the first render list is less than one screen, the "onEndReached" method will still execute automatically.

I really don't know why these problems will arise. If anyone knows the reasons, please explain them.

[react-native-bot]

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