type '(BuildContext, int) => dynamic' is not a subtype of type '(BuildContext, int) => Widget'
源码如下：
import 'package:flutter/material.dart';
import 'post.dart'; void main() {
runApp(MaterialApp(
title: 'Returning Data',
home: HomePage(),
));
} class HomePage extends StatelessWidget {
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text('Flutter SnackBar'),
),
body: Center(
child: new ListViewLayout(),
));
}
} class ListViewLayout extends StatelessWidget {
_istviewItemBuilder(BuildContext context, int index) {
return Text(posts[index].author);
} @override
Widget build(BuildContext context) {
return ListView.builder(
itemCount: posts.length, itemBuilder: _istviewItemBuilder);
}
}
原因是因为_istviewItemBuilder没写 返回值类型Widget 加上就可以
import 'package:flutter/material.dart';
import 'post.dart'; void main() {
runApp(MaterialApp(
title: 'Returning Data',
home: HomePage(),
));
} class HomePage extends StatelessWidget {
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text('Flutter SnackBar'),
),
body: Center(
child: new ListViewLayout(),
));
}
} class ListViewLayout extends StatelessWidget {
Widget _istviewItemBuilder(BuildContext context, int index) {
return Text(posts[index].author);
} @override
Widget build(BuildContext context) {
return ListView.builder(
itemCount: posts.length, itemBuilder: _istviewItemBuilder);
}
}