dart - Flutter:在有状态小部件内使用有状态小部件数组会导致 'A RenderFlex overflow'

我正在学习Flutter，在构建一个简单的应用程序时遇到了这种奇怪的行为。我已经创建了一个自定义的有状态小部件，而我根本无法在另一个有状态小部件中使用它。这是预期的行为还是我在这里丢失了一些东西？

错误是:



和



编码:

import 'package:flutter/material.dart';

void main() => runApp(new MyApp());

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return new MaterialApp(
      title: 'Stateful Widget 02',
      theme: new ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: new MyHomePage(),
    );
  }
}

class MyHomePage extends StatefulWidget {
  MyHomePage({Key key}) : super(key: key);


  @override
  _MyHomePageState createState() => new _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {

  @override
  Widget build(BuildContext context) {
    return new Scaffold(
      appBar: new AppBar(
        title: new Text('Testing nested Stateful Widgets'),
      ),
      body: new Center(
        child: new Column(
          mainAxisAlignment: MainAxisAlignment.center,
          crossAxisAlignment: CrossAxisAlignment.center,
          children: <Widget>[
            new TextCard(),
            new TextCard()
          ],
        ),
      ),
    );
  }
}


class TextCard extends StatefulWidget {
  @override
  State<StatefulWidget> createState() {
    _TextCardState createState() => new _TextCardState();
  }
}

class _TextCardState extends State<TextCard> {

  @override
  Widget build(BuildContext context) {
    return new Card(
        child: new Text('12312')
    );
  }
}

最佳答案

您以错误的方式覆盖了createState()中的TextCard。

替换:

createState() {
    _TextCardState createState() => new _TextCardState();
  }

使用:

@override
_TextCardState createState(){
    return new _TextCardState();
  }