class MyHomePage extends StatefulWidget { MyHomePage({Key key, this.title}) : super(key: key); final String title; @override _MyHomePageState createState() => _MyHomePageState(); } 有状态微件(StatefulWidget)表示这个微件可以拥有自己的状态:_MyHomePageState。调用_MyHomePageState中的setState()方法...
/// Class that stores list item info:/// [id] - unique identifier, number./// [icon] - icon to display in UI./// [title] - text title of the item./// [description] - text description of the item.classItemModel{// class constructorItemModel(this.id,this.icon,this.title,this.d...
# 定义一个与class同名的constructorFly(this.game,double x,double y){flyRect=Rect.fromLTWH(x,y,game.tileSize,game.tileSize);} 这个constructor接收3个参数,一个是父级的game类,将它绑定给刚刚创建的game变量,剩下的x和y代表苍蝇出现的位置。 在constructor中,我们使用传入的x和y以及父类game中的tileSize...
Can't define a const constructor for a class with non-final fields. (Documentation) Try making all of the fields final, or removing the keyword 'const' from the constructor. 1. 我们自定义的 StudentWidget 继承了 StatelessWidget 类 , StatelessWidget 继承了 Widget ; abstract class StatelessWidget ...
// ignore: prefer_const_constructors_in_immutables , never use const for this class UniqueKey(); @override String toString() => '[#${shortHash(this)}]'; 这里我们可以看出这个UniqueKey是产生了一个随机值的字符串,所以这里一定是唯一的。
class Person{ int age; String name; //构造函数Constructor: 函数名与class名一致.用于在初始化对象时直接传进参数然后初始化,在创建对象的时候可以直接调用; //类似于C++中的析构函数 Person (int age,String name){ this.age = age; this.name = name; ...
// expansionPanelList.dart // ignore_for_file: prefer_const_constructors import 'package:flutter/material.dart'; class ExpansionPanelListDemo extends StatefulWidget { const ExpansionPanelListDemo({Key? key}) : super(key: key); @override _ExpansionPanelListDemoState createState() => _ExpansionPanelLis...
// ignore_for_file: prefer_const_constructorsimport'package:flutter/material.dart'; main(List<String> args) { runApp(MyApp()); }classMyAppextendsStatelessWidget{constMyApp({Key? key}) :super(key: key);@overrideWidget build(BuildContext context) {returnMaterialApp( ...
classDetailScreenextendsStatelessWidget{// Declare a field that holds the Todofinal Todo todo;// In the constructor, require a TodoDetailScreen({Key key,@requiredthis.todo}):super(key:key);@override Widgetbuild(BuildContext context){// Use the Todo to create our UIreturnnewScaffold(appBar:new...
class WidgetCreateParam { String constructorName; /// 构建的名称 dynamic context; /// 构建的上下文 Map<String, dynamic> arguments = <String, dynamic>{}; /// 字典参数 List<dynamic> argumentsList = <dynamic>[]; /// 列表参数 dynamic data; /// 原始数据 ...