flutter-sport/lib/widgets/linear_progress_indicator.dart

import 'dart:math';

import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';

class LinearProgressIndicator extends CustomPainter {
  final List<Color> colors;
  final double progress;

  LinearProgressIndicator(this.colors, this.progress);

  @override
  void paint(Canvas canvas, Size size) {
    Rect rect = Rect.fromLTRB(0, 0, size.width * min(1.0, progress), size.height);
    Paint valuePaint = Paint()
      ..shader = LinearGradient(
        begin: Alignment.centerLeft,
        end: Alignment.centerRight,
        colors: colors,
      ).createShader(rect);
    canvas.drawRect(rect, valuePaint);
  }

  @override
  bool shouldRepaint(covariant CustomPainter oldDelegate) {
    return false;
  }
}