fis_lib_measure/lib/view/loadding/loadding.dart

import 'package:fis_ui/index.dart';
import 'package:flutter/widgets.dart';

class SpinKitChasingDots extends StatefulWidget implements FWidget {
  const SpinKitChasingDots({
    Key? key,
    this.color,
    this.size = 50.0,
    this.itemBuilder,
    this.duration = const Duration(milliseconds: 2000),
  })  : assert(
            !(itemBuilder is IndexedWidgetBuilder && color is Color) &&
                !(itemBuilder == null && color == null),
            'You should specify either a itemBuilder or a color'),
        super(key: key);

  final Color? color;
  final double size;
  final IndexedWidgetBuilder? itemBuilder;
  final Duration duration;

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

class _SpinKitChasingDotsState extends State<SpinKitChasingDots>
    with TickerProviderStateMixin {
  late AnimationController _scaleCtrl;
  late AnimationController _rotateCtrl;
  late Animation<double> _scale;
  late Animation<double> _rotate;

  @override
  void initState() {
    super.initState();

    _scaleCtrl = AnimationController(vsync: this, duration: widget.duration)
      ..addListener(() => setState(() {}))
      ..repeat(reverse: true);
    _scale = Tween(begin: -1.0, end: 1.0)
        .animate(CurvedAnimation(parent: _scaleCtrl, curve: Curves.easeInOut));

    _rotateCtrl = AnimationController(vsync: this, duration: widget.duration)
      ..addListener(() => setState(() {}))
      ..repeat();
    _rotate = Tween(begin: 0.0, end: 360.0)
        .animate(CurvedAnimation(parent: _rotateCtrl, curve: Curves.linear));
  }

  @override
  void dispose() {
    _scaleCtrl.dispose();
    _rotateCtrl.dispose();
    super.dispose();
  }

  @override
  FWidget build(BuildContext context) {
    return QuickFWidget(
      Center(
        child: SizedBox.fromSize(
          size: Size.square(widget.size),
          child: Transform.rotate(
            angle: _rotate.value * 0.0174533,
            child: Stack(
              children: <Widget>[
                Positioned(
                    top: 0.0, child: _circle(1.0 - _scale.value.abs(), 0)),
                Positioned(bottom: 0.0, child: _circle(_scale.value.abs(), 1)),
              ],
            ),
          ),
        ),
      ),
    );
  }

  Widget _circle(double scale, int index) {
    return Transform.scale(
      scale: scale,
      child: SizedBox.fromSize(
        size: Size.square(widget.size * 0.6),
        child: widget.itemBuilder != null
            ? widget.itemBuilder!(context, index)
            : DecoratedBox(
                decoration:
                    BoxDecoration(shape: BoxShape.circle, color: widget.color)),
      ),
    );
  }
}

class QuickFWidget extends StatelessWidget implements FWidget {
  const QuickFWidget(this.child, {Key? key}) : super(key: key);
  final Widget child;
  @override
  Widget build(BuildContext context) => child;
}