需要添加依赖 get: 4.6.5

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

class VDPageControl extends StatefulWidget {
  const VDPageControl({
    required this.pageController,
    required this.width,
    required this.height,
    required this.numberOfPages,
    this.currentPage = 0,
    this.defaultColor = Colors.grey,
    this.currentColor = Colors.white,
    this.space = 5,
    this.dotWidth = 5,
    this.dotHeight = 5,
    this.currentDotWidth = 10,
    this.currentDotHeight = 5,
    this.dotRadius = 2,
    super.key,
  });
  final PageController pageController;
  final int numberOfPages;

  final int currentPage;

  final Color defaultColor;

  final Color currentColor;

  final double space;

  final double width;

  final double height;

  final double dotWidth;

  final double dotHeight;

  final double currentDotWidth;

  final double currentDotHeight;

  final double dotRadius;

  @override
  State createState() {
    return _PageControlState();
  }
}

class _PageControlState extends State<VDPageControl> {
  final RxInt rxPage = 0.obs;

  @override
  void initState() {
    super.initState();
    rxPage(widget.currentPage);
    widget.pageController.addListener(onPageControllerNotify);
  }

  @override
  void dispose() {
    widget.pageController.removeListener(onPageControllerNotify);
    super.dispose();
  }

  void onPageControllerNotify() {
    rxPage(widget.pageController.page?.round() ?? 0);
  }

  BoxDecoration get currentDecoration => BoxDecoration(
        borderRadius: BorderRadius.all(Radius.circular(widget.dotRadius)),
        color: widget.currentColor,
      );

  BoxDecoration get defaultDecoration => BoxDecoration(
        color: widget.defaultColor,
        borderRadius: BorderRadius.all(Radius.circular(widget.dotRadius)),
      );

  @override
  Widget build(BuildContext context) {
    return Container(
      width: widget.width,
      height: widget.height,
      alignment: Alignment.center,
      color: Colors.transparent,
      child: SingleChildScrollView(
        child: Row(
          mainAxisAlignment: MainAxisAlignment.center,
          children: List<Widget>.generate(widget.numberOfPages, cell),
        ),
      ),
    );
  }

  Widget cell(int index) {
    return Obx(() => Center(
          child: Container(
            margin: EdgeInsets.fromLTRB(0, 0, widget.space, 0),
            width: index == rxPage.value ? widget.currentDotWidth : widget.dotWidth,
            height: index == rxPage.value ? widget.currentDotHeight : widget.dotHeight,
            decoration: index == rxPage.value ? currentDecoration : defaultDecoration,
          ),
        ));
  }
}