Flutter -当Provider变量更改时触发导航

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

void main() {
  runApp(
    ChangeNotifierProvider(
      create: (context) => UserProvider(),
      child: MyApp(),
    ),
  );
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(title: Text('Provider Navigation Example')),
        body: HomeScreen(),
      ),
    );
  }
}

class UserProvider with ChangeNotifier {
  bool _isLoggedIn = false;

  bool get isLoggedIn => _isLoggedIn;

  void login() {
    _isLoggedIn = true;
    notifyListeners();
  }

  void logout() {
    _isLoggedIn = false;
    notifyListeners();
  }
}

class HomeScreen extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Consumer<UserProvider>(
      builder: (context, userProvider, child) {
        if (userProvider.isLoggedIn) {
          return NavigateToDashboard();
        } else {
          return LoginScreen(userProvider);
        }
      },
    );
  }
}

class LoginScreen extends StatelessWidget {
  final UserProvider userProvider;

  LoginScreen(this.userProvider);

  @override
  Widget build(BuildContext context) {
    return Center(
      child: ElevatedButton(
        onPressed: () {
          userProvider.login();
        },
        child: Text('Login'),
      ),
    );
  }
}

class NavigateToDashboard extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Center(
      child: Text('Welcome to Dashboard!'),
    );
  }
}