MaterialState
sample.packages.flutter.lib.src.material.material_state.379.
This example defines a subclass of [RoundedRectangleBorder] and an implementation of [MaterialStateOutlinedBorder], that resolves to [RoundedRectangleBorder] when its widget is selected.
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: MyStatefulWidget(),
);
}
}
class SelectedBorder extends RoundedRectangleBorder
implements MaterialStateOutlinedBorder {
@override
OutlinedBorder? resolve(Set states) {
if (states.contains(MaterialState.selected)) {
return const RoundedRectangleBorder();
}
return null; // Defer to default value on the theme or widget.
}
}
class MyStatefulWidget extends StatefulWidget {
const MyStatefulWidget({Key? key}) : super(key: key);
@override
State createState() => _MyStatefulWidgetState();
}
class _MyStatefulWidgetState extends State {
bool isSelected = true;
@override
Widget build(BuildContext context) {
return Material(
child: FilterChip(
label: const Text('Select chip'),
selected: isSelected,
onSelected: (bool value) {
setState(() {
isSelected = value;
});
},
shape: SelectedBorder(),
),
);
}
}
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