Код: Выделить всё
import 'package:circular_countdown_timer/circular_countdown_timer.dart';
import 'package:flutter/material.dart';
void main() {
runApp(const MyApp());
}
class MyApp extends StatelessWidget {
const MyApp({super.key});
@override
Widget build(BuildContext context) {
return MaterialApp(
theme: ThemeData(
primarySwatch: Colors.blue,
),
home: const MyHomePage(),
);
}
}
class MyHomePage extends StatefulWidget {
const MyHomePage({
super.key,
});
@override
State createState() => _MyHomePageState();
}
class _MyHomePageState extends State {
Color fillColor = Colors.black;
int duration = 500;
@override
Widget build(BuildContext context) {
return Scaffold(
body: Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: [
CircularCountDownTimer(
isReverse: true,
textStyle: TextStyle(fontSize: 40),
strokeWidth: 13,
width: 200,
height: 200,
duration: duration,
fillColor: fillColor,
ringColor: Colors.blue),
Padding(
padding: const EdgeInsets.all(28.0),
child: ElevatedButton(
onPressed: () {
setState(() {
fillColor = fillColor == Colors.redAccent
? Colors.black
: Colors.redAccent;
duration = duration == 800 ? 500 : 800;
});
},
child: Text('Press !')),
)
],
),
),
);
}
}

Подробнее здесь: https://stackoverflow.com/questions/787 ... -its-state