颤动:在状态窗口小部件中使用状态窗口小部件数组会导致“渲染文件溢出”溢出'

时间:2018-02-28 03:44:01

标签: dart flutter

我正在学习Flutter,我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状态窗口小部件,我根本无法在另一个状态窗口小部件中使用它。这是预期的行为还是我在这里遗漏了什么?

错误是:

  

引发了以下NoSuchMethodError构建   MediaQuery(MediaQueryData(尺寸:大小(375.0,       812.0),devicePixelRatio:3.0,textScaleFactor:1.0,填充:EdgeInsets(0.0,0.0,0.0,34.0),       viewInsets:EdgeInsets.zero,alwaysUse24HourFormat:false)):       方法' _debugTypesAreRight'在null上调用。       接收者:null       尝试调用:_debugTypesAreRight(实例' TextCard')

  

抛出了另一个异常:_ScaffoldLayout自定义multichild   布局代表忘了布置下面的孩子:

代码:

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')
    );
  }
}

1 个答案:

答案 0 :(得分:8)

您以错误的方式覆盖createState()中的TextCard

<强>替换

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

。通过

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