AiKeyboard2025/lib/widget/animated_progress_bar.dart

import 'package:flutter/material.dart';

import 'bubble/bubble_widget.dart';

/// 支持动画过渡和渐变色的进度条
// 使用示例
// AnimatedGradientProgressBar(
//   targetValue: 0.75,
//   gradient: LinearGradient(colors: [Colors.orange, Colors.red]),
//   height: 10,
//   borderRadius: 5,
// )
class AnimatedGradientProgressBar extends StatefulWidget {
  // 目标进度值（0~1）
  final double targetValue;

  // 动画时长
  final Duration duration;

  // 渐变色
  final Gradient gradient;

  // 进度条高度
  final double height;

  // 圆角半径
  final double borderRadius;

  const AnimatedGradientProgressBar({
    super.key,
    required this.targetValue,
    required this.duration,
    required this.gradient,
    this.height = 10.0,
    this.borderRadius = 7.0,
  });

  @override
  AnimatedGradientProgressBarState createState() =>
      AnimatedGradientProgressBarState();
}

class AnimatedGradientProgressBarState
    extends State<AnimatedGradientProgressBar>
    with TickerProviderStateMixin {
  late AnimationController _controller;
  late Animation<double> _animation;

  @override
  void initState() {
    super.initState();
    _controller = AnimationController(duration: widget.duration, vsync: this);
    _animation = CurvedAnimation(parent: _controller, curve: Curves.easeInOut);
    _startAnimation();
  }

  @override
  void didUpdateWidget(AnimatedGradientProgressBar oldWidget) {
    super.didUpdateWidget(oldWidget);
    if (oldWidget.targetValue != widget.targetValue) {
      _resetAnimation();
      _startAnimation();
    }
  }

  @override
  void dispose() {
    // 移除监听
    _animation.removeListener(() {});
    _controller.dispose();
    super.dispose();
  }

  void _startAnimation() {
    print('进度条 => 初始动画值: ${_animation.value}'); // 0.0

    // 先移除旧监听
    _animation.removeListener(() {});

    // 创建新的 Tween 动画
    _animation = Tween<double>(
      begin: 0,
      end: widget.targetValue,
    ).animate(_animation);

    // 添加监听器并启动动画
    _animation.addListener(() => setState(() {}));
    _controller.forward();

    Future.delayed(widget.duration, () {
      print('进度条 => 最终动画值: ${_animation.value}');
    });
  }

  void _resetAnimation() => _controller.reset();

  @override
  Widget build(BuildContext context) {
    return LayoutBuilder(
      builder: (context, constraints) {
        // 进度条的实际宽度
        final progressBarWidth = constraints.maxWidth;
        // 计算气泡距离左边的偏移量
        double leftOffset = 0;
        if (_animation.value == 0) {
          leftOffset = 0;
        } else {
          leftOffset =
              _animation.value * progressBarWidth -
              (widget.targetValue > 0.5 ? 32 : 24);
        }
        return Stack(
          // 允许子组件溢出自己本身的大小，默认是裁切的
          clipBehavior: Clip.none,
          children: [
            // 百分比文本
            Positioned(
              // 左侧偏移量，气泡跟随在当前进度的末尾，公式：当前比例值 * 进度条的宽度 - 气泡宽度
              left: leftOffset,
              // 进度气泡，位于进度条上方
              bottom: widget.height + 0.85,
              child: AnimatedBuilder(
                animation: _animation,
                builder: (context, _) {
                  return BubbleWidget(
                    // 箭头方向
                    arrowDirection: AxisDirection.down,
                    // 箭头距离左边的偏移量
                    arrowOffset: leftOffset == 0 ? 10 : 22,
                    arrowLength: 8,
                    arrowRadius: 2,
                    arrowWidth: 5,
                    padding: const EdgeInsets.symmetric(
                      vertical: 2,
                      horizontal: 7,
                    ),
                    borderRadius: BorderRadius.circular(9),
                    // 气泡的背景颜色，取渐变色的第2个颜色
                    backgroundColor: widget.gradient.colors.last,
                    contentBuilder: (context) {
                      return Text(
                        '${(_animation.value * 100).toStringAsFixed(0)}%',
                        style: const TextStyle(
                          fontSize: 10,
                          color: Colors.white,
                        ),
                      );
                    },
                  );
                },
              ),
            ),
            // 进度条
            ClipRRect(
              borderRadius: BorderRadius.circular(widget.borderRadius),
              child: Container(
                width: double.infinity,
                height: widget.height,
                decoration: BoxDecoration(
                  color: Colors.grey[200],
                  borderRadius: BorderRadius.circular(widget.borderRadius),
                ),
                child: Stack(
                  children: [
                    AnimatedBuilder(
                      animation: _animation,
                      builder: (context, _) {
                        return FractionallySizedBox(
                          widthFactor: _animation.value,
                          alignment: Alignment.centerLeft,
                          child: Container(
                            decoration: BoxDecoration(
                              gradient: widget.gradient,
                              borderRadius: BorderRadius.circular(
                                widget.borderRadius,
                              ),
                            ),
                          ),
                        );
                      },
                    ),
                  ],
                ),
              ),
            ),
          ],
        );
      },
    );
  }
}