Generate GridView with flutter using index - flutter

Question

what I am trying to do is generate a GridView with flutter with the index which is defined above, but it said "Undefined name index" for some reason, can you help me with that please.
Here is the code:
import 'package:flutter/material.dart';
void main() => runApp(MyApp(items: List<String>.generate(1000, (index) => "Item $index")));
class MyApp extends StatelessWidget {
final List<String> items;
MyApp({Key key, #required this.items}) : super(key: key);
// This widget is the root of your application.
#override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
theme: ThemeData(
primarySwatch: Colors.blue,
),
home: Scaffold(
appBar:
AppBar(title:
Text('List View Vertical'),),
body:
GridView.count(
crossAxisCount: 2,
children: List.generate(100, index)(
return Center(child: Text('Items $index',
style: Theme.of(context).textTheme.headline,),);
))
)
);
}
}
The result I expect is generating 1000 rows of gridview using the index I have already defined.

Answer 1

Replace your build() with this:
#override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
theme: ThemeData(
primarySwatch: Colors.blue,
),
home: Scaffold(
appBar: AppBar(
title: Text('List View Vertical'),
),
body: GridView.count(
crossAxisCount: 2,
children: items.map((title) {
return Center(
child: Text(
'$title',
style: Theme.of(context).textTheme.headline,
),
);
}).toList(),
),
),
);
}

Answer 2

Change your code to use the values from the property items that your are passing.
Example:
class MyApp extends StatelessWidget {
final List<String> items;
MyApp({Key key, #required this.items}) : super(key: key);
// This widget is the root of your application.
#override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
theme: ThemeData(
primarySwatch: Colors.blue,
),
home: Scaffold(
appBar: AppBar(
title: Text('List View Vertical'),
),
body: GridView.count(
crossAxisCount: 2,
children: items.map((text) {
return Center(
child: Text(
'$text',
style: Theme.of(context).textTheme.headline,
),
);
}).toList(),
),
),
);
}
}