mileograph_flutter/lib/components/widgets/animated_count_text.dart

import 'package:flutter/material.dart';

class AnimatedCountText extends StatefulWidget {
  const AnimatedCountText({
    super.key,
    required this.value,
    required this.formatter,
    this.style,
    this.duration = const Duration(milliseconds: 900),
    this.curve = Curves.easeOutCubic,
    this.animateFromZero = true,
  });

  final double value;
  final String Function(double) formatter;
  final TextStyle? style;
  final Duration duration;
  final Curve curve;
  final bool animateFromZero;

  @override
  State<AnimatedCountText> createState() => _AnimatedCountTextState();
}

class _AnimatedCountTextState extends State<AnimatedCountText>
    with SingleTickerProviderStateMixin {
  late AnimationController _controller;
  late Animation<double> _animation;
  late CurvedAnimation _curve;
  double _currentValue = 0;

  @override
  void initState() {
    super.initState();
    _currentValue = widget.animateFromZero ? 0 : widget.value;
    _controller = AnimationController(vsync: this, duration: widget.duration);
    _curve = CurvedAnimation(parent: _controller, curve: widget.curve);
    _controller.addListener(_handleTick);
    _configureAnimation(from: _currentValue, to: widget.value);
    if (_currentValue != widget.value) {
      _controller.forward();
    }
  }

  @override
  void didUpdateWidget(covariant AnimatedCountText oldWidget) {
    super.didUpdateWidget(oldWidget);
    if (oldWidget.curve != widget.curve) {
      _curve = CurvedAnimation(parent: _controller, curve: widget.curve);
      _configureAnimation(from: _currentValue, to: widget.value);
    }
    if (oldWidget.value != widget.value) {
      _controller.duration = widget.duration;
      _configureAnimation(from: _currentValue, to: widget.value);
      _controller.forward(from: 0);
    }
  }

  void _configureAnimation({required double from, required double to}) {
    _animation = Tween<double>(begin: from, end: to).animate(_curve);
  }

  void _handleTick() {
    setState(() => _currentValue = _animation.value);
  }

  @override
  void dispose() {
    _controller.removeListener(_handleTick);
    _controller.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return Text(
      widget.formatter(_currentValue),
      style: widget.style,
    );
  }
}