Listview Builder On Scroll child == null 或 hasSize == null 等

Question

尽我所能

> import 'package:alnoor/poTesting/poClass.dart';
>     import 'package:alnoor/poTesting/poTestingForm.dart';
>     import 'package:flutter/material.dart';
>     
>     class PoTesting extends StatefulWidget {
>       PoTesting({Key key}) : super(key: key);
>     
>       _PoTestingState createState() => _PoTestingState();
>     }
>     
>     class _PoTestingState extends State<PoTesting> {
>       List itemList = [];
>       @override
>       Widget build(BuildContext context) {
>         var _user = User();
>     
>         return Scaffold(
>             appBar: AppBar(
>               title: Text("data"),
>             ),
>             floatingActionButton: FloatingActionButton(
>               child: Icon(Icons.add),
>               onPressed: () {
>                 setState(() {
>                   itemList.add("value");
>                 });
>               },
>             ),
>             body: Container(
>               height: 500,
>               child: new ListView.builder(
>                 addRepaintBoundaries: true,
>                 shrinkWrap: true,
>                 itemCount: 25,
>                 itemBuilder: (context, i) {
>                   return UserForm(
>                     user: _user,
>                   );
>                 },
>               ),
>             ));
>       }
>     }

Answer 1

问题解决参考github 由于每次在创建新小部件时创建新的状态实例而出现问题它只呈现前三个小部件状态不知道为什么所以我每次都停止验证状态

Listview Builder On Scroll child == null 或 hasSize == null 等

Listview Builder On Scroll child == null or hasSize == null etc

flutter-listview