使用flutter从BottomNavigationBar上的按钮注销用户

class MyHomePage extends StatefulWidget {
  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  int _currentIndex = 0;

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text("My App"),
      ),
      body: Center(
        child: Text("Content of the current page"),
      ),
      bottomNavigationBar: BottomNavigationBar(
        currentIndex: _currentIndex,
        onTap: (int index) {
          setState(() {
            _currentIndex = index;
            if (index == 3) {
              // 注销按钮点击事件
              _logoutUser();
            }
          });
        },
        items: [
          BottomNavigationBarItem(
            icon: Icon(Icons.home),
            title: Text("Home"),
          ),
          BottomNavigationBarItem(
            icon: Icon(Icons.search),
            title: Text("Search"),
          ),
          BottomNavigationBarItem(
            icon: Icon(Icons.favorite),
            title: Text("Favorites"),
          ),
          BottomNavigationBarItem(
            icon: Icon(Icons.exit_to_app),
            title: Text("Logout"),
          ),
        ],
      ),
    );
  }

  // 注销用户方法
  void _logoutUser() {
    // 在此处执行注销用户的逻辑，比如清除用户登录状态、清除缓存等操作
    // 然后跳转到登录页面
    Navigator.pushReplacement(
      context,
      MaterialPageRoute(builder: (context) => LoginPage()),
    );
  }
}

class LoginPage extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text("Login"),
      ),
      body: Center(
        child: RaisedButton(
          child: Text("Login"),
          onPressed: () {
            // 在此处处理登录操作，比如验证用户输入、请求后端接口等
            // 登录成功后，跳转到主页
            Navigator.pushReplacement(
              context,
              MaterialPageRoute(builder: (context) => MyHomePage()),
            );
          },
        ),
      ),
    );
  }
}