selfprivacy.org.app/lib/ui/components/progress_bar/progress_bar.dart

import 'package:flutter/material.dart';

class ProgressBar extends StatefulWidget {
  const ProgressBar({
    required this.steps,
    required this.activeIndex,
    super.key,
  });

  final int activeIndex;

  final List<String> steps;

  @override
  State<ProgressBar> createState() => _ProgressBarState();
}

class _ProgressBarState extends State<ProgressBar> {
  @override
  Widget build(final BuildContext context) {
    final double progress =
        1 / widget.steps.length * (widget.activeIndex + 0.3);

    return Column(
      crossAxisAlignment: CrossAxisAlignment.start,
      children: [
        Container(
          alignment: Alignment.centerLeft,
          decoration: BoxDecoration(
            color: Theme.of(context).colorScheme.surfaceVariant,
            borderRadius: BorderRadius.circular(5),
          ),
          child: LayoutBuilder(
            builder: (final _, final constraints) => AnimatedContainer(
              width: constraints.maxWidth * progress,
              height: 5,
              decoration: BoxDecoration(
                borderRadius: BorderRadius.circular(5),
                color: Theme.of(context).colorScheme.surfaceVariant,
                gradient: LinearGradient(
                  begin: Alignment.topLeft,
                  end: Alignment.bottomRight,
                  colors: [
                    Theme.of(context).colorScheme.primary,
                    Theme.of(context).colorScheme.secondary,
                  ],
                ),
              ),
              duration: const Duration(
                milliseconds: 300,
              ),
            ),
          ),
        ),
      ],
    );
  }
}