Flutter Log Out &完美替换堆栈

import 'package:flutter/material.dart';

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: HomePage(),
      routes: {
        '/login': (context) => LoginPage(),
        '/dashboard': (context) => DashboardPage(),
      },
    );
  }
}

class HomePage extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Home'),
      ),
      body: Center(
        child: RaisedButton(
          child: Text('Log Out'),
          onPressed: () {
            Navigator.pushReplacementNamed(context, '/login');
          },
        ),
      ),
    );
  }
}

class LoginPage extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Login'),
      ),
      body: Center(
        child: RaisedButton(
          child: Text('Log In'),
          onPressed: () {
            Navigator.pushReplacementNamed(context, '/dashboard');
          },
        ),
      ),
    );
  }
}

class DashboardPage extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Dashboard'),
      ),
      body: Center(
        child: Text('Welcome to the Dashboard!'),
      ),
    );
  }
}