Datasets:
Ekhlass
/
flutter_docs

Dataset card Data Studio Files
xet
Community
1
text
stringlengths
1
372
<topic_end>
<topic_start>
interactive example
this example shows a list of items that are spaced evenly within a column.
the list can be scrolled up and down when the items don’t fit the screen.
the number of items is defined by the variable items,
change this value to see what happens when the items won’t fit the screen.
<code_start>
import 'package:flutter/material.dart';
void main() => runApp(const SpacedItemsList());
class SpacedItemsList extends StatelessWidget {
const SpacedItemsList({super.key});
@override
widget build(BuildContext context) {
const items = 4;
return MaterialApp(
title: 'flutter demo',
debugShowCheckedModeBanner: false,
theme: ThemeData(
colorScheme: ColorScheme.fromSeed(seedColor: Colors.deepPurple),
cardTheme: CardTheme(color: colors.blue.shade50),
useMaterial3: true,
),
home: scaffold(
body: LayoutBuilder(builder: (context, constraints) {
return SingleChildScrollView(
child: ConstrainedBox(
constraints: BoxConstraints(minHeight: constraints.maxHeight),
child: column(
mainAxisAlignment: MainAxisAlignment.spaceBetween,
crossAxisAlignment: CrossAxisAlignment.stretch,
children: list.generate(
items, (index) => ItemWidget(text: 'item $index')),
),
),
);
}),
),
);
}
}
class ItemWidget extends StatelessWidget {
const ItemWidget({
super.key,
required this.text,
});
final string text;
@override
widget build(BuildContext context) {
return card(
child: SizedBox(
height: 100,
child: center(child: text(text)),
),
);
}
}
<code_end>
<topic_end>
<topic_start>
work with long lists
the standard ListView constructor works well
for small lists. to work with lists that contain
a large number of items, it’s best to use the
ListView.builder constructor.
in contrast to the default ListView constructor, which requires
creating all items at once, the ListView.builder() constructor
creates items as they’re scrolled onto the screen.
<topic_end>
<topic_start>
1. create a data source
first, you need a data source. for example, your data source
might be a list of messages, search results, or products in a store.
most of the time, this data comes from the internet or a database.
for this example, generate a list of 10,000 strings using the
list.generate constructor.
<code_start>
List<String>.generate(10000, (i) => 'item $i'),
<code_end>
<topic_end>
<topic_start>
2. convert the data source into widgets
to display the list of strings, render each string as a widget
using ListView.builder().
in this example, display each string on its own line.
<code_start>
ListView.builder(
itemCount: items.length,
prototypeItem: ListTile(
title: text(items.first),
),
itemBuilder: (context, index) {
return ListTile(
title: text(items[index]),
);
},
)
<code_end>
<topic_end>
<topic_start>