参数类型"列表"不能<dynamic>分配给参数类型"列表<Widget>"

Question

我得到上述错误(问题)与以下代码:

Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(title: const Text('DeliMeals')),
body: GridView(
children: DUMMY_CATEGORIES
.map((categoryData) => CategoryItem(   //getting
categoryData.title,             //the error
categoryData.color,            //here
))
.toList(),

dummy_data

const DUMMY_CATEGORIES = const [
Category(
id: 'c1',
title: 'Italian',
color: Colors.purple,
),
Category(
id: 'c2',
title: 'Quick & Easy',
color: Colors.red,
),
];

我只是在遵循一个教程。指导员没有得到错误。(

Answer 1

指定map<Widget>的地图类型

DUMMY_CATEGORIES
.map<Widget>((categoryData) => CategoryItem(   
categoryData.title,             
categoryData.color,            
))
.toList(),