How Do You Create a Custom Circular Progress Indicator in Flutter?

You can create a custom circular progress indicator in Flutter using the CustomPaint widget and the Canvas object.

Steps to Create a Custom Circular Progress Indicator

Create a CustomPainter class: This class will define how to draw the progress indicator.
Override the paint() method: This method receives a Canvas object, which you can use to draw on the widget.
Draw the circular progress indicator: Use the Canvas methods to draw the circular path, fill it with the appropriate color, and add any necessary decorations.
Use the CustomPaint widget: Wrap your CustomPainter class in a CustomPaint widget to display the progress indicator.

Example Code:

import 'package:flutter/material.dart';

class CircularProgressIndicatorCustom extends CustomPainter {
  final double progress;

  CircularProgressIndicatorCustom({required this.progress});

  @override
  void paint(Canvas canvas, Size size) {
    final paint = Paint()
      ..color = Colors.blue
      ..strokeWidth = 10.0
      ..style = PaintingStyle.stroke
      ..strokeCap = StrokeCap.round;

    final center = Offset(size.width / 2, size.height / 2);
    final radius = size.width / 2 - 10.0;

    final arcAngle = 2 * pi * progress;

    canvas.drawArc(
      Rect.fromCircle(center: center, radius: radius),
      -pi / 2,
      arcAngle,
      false,
      paint,
    );
  }

  @override
  bool shouldRepaint(covariant CustomPainter oldDelegate) {
    return oldDelegate != this;
  }
}

Usage:

CustomPaint(
  size: Size(100, 100),
  painter: CircularProgressIndicatorCustom(progress: 0.75),
)

Customization Options:

Color: Change the color of the progress indicator using the color property of the Paint object.
Width: Adjust the width of the progress indicator using the strokeWidth property of the Paint object.
Stroke Cap: Customize the end points of the progress indicator using the strokeCap property of the Paint object.
Animation: Animate the progress indicator using a TweenAnimationBuilder widget.

Conclusion:

By understanding the basic principles and using the CustomPaint widget, you can easily create customized circular progress indicators in Flutter to fit your specific design requirements.

A2oz