flutter error: The method 'CustomTimerPainter' isn't defined for the class '_CountDownTimerState - flutter

Question

This is what it shows in terminal
59:48: Error: The method 'CustomTimerPainter' isn't defined for the
class '_CountDownTimerState'.
'_CountDownTimerState' is from 'package:braintrinig/pages/Countdown_timer.dart'
('lib/pages/Countdown_timer.dart'). Try correcting the name to the
name of an existing method, or defining a method named
'CustomTimerPainter'.
painter: CustomTimerPainter(
How to solve this issue?
This is my code:
import 'package:flutter/material.dart';
import 'package:flutter/cupertino.dart';
class CountDownTimer extends StatefulWidget {
#override
_CountDownTimerState createState() => _CountDownTimerState();
}
class _CountDownTimerState extends State<CountDownTimer>
with TickerProviderStateMixin {
late AnimationController controller;
String get timerString {
Duration duration = controller.duration! * controller.value;
return '${duration.inMinutes}:${(duration.inSeconds % 60).toString().padLeft(2, '0')}';
}
#override
void initState() {
super.initState();
controller = AnimationController(
vsync: this,
duration: Duration(seconds: 5),
);
}
#override
Widget build(BuildContext context) {
ThemeData themeData = Theme.of(context);
return Scaffold(
backgroundColor: Colors.white10,
body:
Container(
color: Colors.amber,
height: controller.value * MediaQuery.of(context).size.height,
child: AnimatedBuilder(
animation: controller,
builder: (context, child) {
return Stack(
children: <Widget>[
Align(
alignment: Alignment.bottomCenter,
child: Container(
color: Colors.amber,
height:
controller.value * MediaQuery.of(context).size.height,
),
),
Padding(
padding: EdgeInsets.all(8.0),
child: Column(
mainAxisAlignment: MainAxisAlignment.spaceBetween,
children: <Widget>[
Expanded(
child: Align(
alignment: FractionalOffset.center,
child: AspectRatio(
aspectRatio: 1.0,
child: Stack(
children: <Widget>[
Positioned.fill(
child: CustomPaint(
painter: CustomTimerPainter(
animation: controller,
backgroundColor: Colors.white,
color: themeData.indicatorColor,
)),
),
Align(
alignment: FractionalOffset.center,
child: Column(
mainAxisAlignment:
MainAxisAlignment.spaceEvenly,
crossAxisAlignment:
CrossAxisAlignment.center,
children: <Widget>[
Text(
"Count Down Timer",
style: TextStyle(
fontSize: 20.0,
color: Colors.white),
),
Text(
timerString,
style: TextStyle(
fontSize: 112.0,
color: Colors.white),
),
],
),
),
],
),
),
),
),
AnimatedBuilder(
animation: controller,
builder: (context, child) {
return FloatingActionButton.extended(
onPressed: () {
if (controller.isAnimating)
controller.stop();
else {
controller.reverse(
from: controller.value == 0.0
? 1.0
: controller.value);
}
},
icon: Icon(controller.isAnimating
? Icons.pause
: Icons.play_arrow),
label: Text(
controller.isAnimating ? "Pause" : "Play"));
}),
],
),
),
],
);
}),
),
);
}
}

Answer 1

It checked that "CustomTimerPainter" is from circular_countdown_timer library.
After you add this library, the problem you mentioned will be resolved.
I pasted your code to my project and install "circular_countdown_timer", I didn't see any error right now.
circular_countdown_timer pub.dev
Add circular_countdown_timer in your pubspec.yaml => get => update.
dependencies:
circular_countdown_timer: ^0.2.2
Import this library into your dart file
import 'package:circular_countdown_timer/custom_timer_painter.dart';

Answer 2

The CustomeTimerPainter is a custom widget that someone has already written in your taken example,
You may please check those examples, or you can use the sample below.
class CustomTimerPainter extends CustomPainter {
CustomTimerPainter({
this.animation,
this.backgroundColor,
this.color,
}) : super(repaint: animation);
final Animation<double> animation;
final Color backgroundColor, color;
#override
void paint(Canvas canvas, Size size) {
Paint paint = Paint()
..color = backgroundColor
..strokeWidth = 10.0
..strokeCap = StrokeCap.butt
..style = PaintingStyle.stroke;
canvas.drawCircle(size.center(Offset.zero), size.width / 2.0, paint);
paint.color = color;
double progress = (1.0 - animation.value) * 2 * math.pi;
canvas.drawArc(Offset.zero & size, math.pi * 1.5, -progress, false, paint);
}
#override
bool shouldRepaint(CustomTimerPainter old) {
return animation.value != old.animation.value ||
color != old.color ||
backgroundColor != old.backgroundColor;
}
}