Scaffold
sample.packages.flutter.lib.src.material.scaffold.1755.
When the [Scaffold] is actually created in the same build
function, the
context
argument to the build
function can't be used to find the
[Scaffold] (since it's "above" the widget being returned in the widget
tree). In such cases, the following technique with a [Builder] can be used
to provide a new scope with a [BuildContext] that is "under" the
[Scaffold]:
import 'package:flutter/material.dart';
void main() => runApp(const MyApp());
class MyApp extends StatelessWidget {
const MyApp({Key? key}) : super(key: key);
static const String _title = 'Flutter Code Sample';
@override
Widget build(BuildContext context) {
return const MaterialApp(
title: _title,
home: MyStatelessWidget(),
);
}
}
class MyStatelessWidget extends StatelessWidget {
const MyStatelessWidget({Key? key}) : super(key: key);
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(title: const Text('Demo')),
body: Builder(
// Create an inner BuildContext so that the onPressed methods
// can refer to the Scaffold with Scaffold.of().
builder: (BuildContext context) {
return Center(
child: ElevatedButton(
child: const Text('SHOW BOTTOM SHEET'),
onPressed: () {
Scaffold.of(context).showBottomSheet(
(BuildContext context) {
return Container(
alignment: Alignment.center,
height: 200,
color: Colors.amber,
child: Center(
child: Column(
mainAxisSize: MainAxisSize.min,
children: [
const Text('BottomSheet'),
ElevatedButton(
child: const Text('Close BottomSheet'),
onPressed: () {
Navigator.pop(context);
},
),
],
),
),
);
},
);
},
),
);
},
),
);
}
}
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