Flutter如何停止自定义画图进度指示器

import 'package:flutter/material.dart';

class CustomProgressIndicator extends StatefulWidget {
  @override
  _CustomProgressIndicatorState createState() => _CustomProgressIndicatorState();
}

class _CustomProgressIndicatorState extends State<CustomProgressIndicator> {
  bool showProgress = true;

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Custom Progress Indicator'),
      ),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            if (showProgress)
              CircularProgressIndicator(), // 根据showProgress变量决定是否显示进度指示器
            RaisedButton(
              child: Text('停止进度指示器'),
              onPressed: () {
                setState(() {
                  showProgress = false; // 停止进度指示器的显示
                });
              },
            ),
          ],
        ),
      ),
    );
  }
}

void main() {
  runApp(MaterialApp(
    home: CustomProgressIndicator(),
  ));
}