flutter:如何在一个图标中实现两条路由

import 'package:flutter/material.dart';

class MyIcon extends StatefulWidget {
  @override
  _MyIconState createState() => _MyIconState();
}

class _MyIconState extends State<MyIcon> {
  bool _isFirstRoute = true;
  
  // ...
}

@override
Widget build(BuildContext context) {
  return GestureDetector(
    onTap: () {
      setState(() {
        _isFirstRoute = !_isFirstRoute;
      });
    },
    child: Icon(Icons.arrow_forward),
  );
}

@override
Widget build(BuildContext context) {
  return GestureDetector(
    onTap: () {
      setState(() {
        _isFirstRoute = !_isFirstRoute;
      });
      
      if (_isFirstRoute) {
        Navigator.push(
          context,
          MaterialPageRoute(builder: (context) => FirstRoute()),
        );
      } else {
        Navigator.push(
          context,
          MaterialPageRoute(builder: (context) => SecondRoute()),
        );
      }
    },
    child: Icon(Icons.arrow_forward),
  );
}