如何只对部分UIViewControllers开启前台通知？

// 注册远程通知
UIApplication.shared.registerForRemoteNotifications()

// 注册本地通知
let center = UNUserNotificationCenter.current()
center.requestAuthorization(options: [.alert, .sound, .badge]) { (granted, error) in
    if granted {
        print("本地通知授权成功")
    } else {
        print("本地通知授权失败")
    }
}

// 在viewDidAppear方法中添加以下代码
override func viewDidAppear(_ animated: Bool) {
    super.viewDidAppear(animated)
    
    // 设置通知代理
    UNUserNotificationCenter.current().delegate = self
    
    // 请求开启前台通知
    let center = UNUserNotificationCenter.current()
    center.requestAuthorization(options: [.alert, .sound, .badge]) { (granted, error) in
        if granted {
            print("前台通知授权成功")
            self.enableForegroundNotification()
        } else {
            print("前台通知授权失败")
        }
    }
}

// 开启前台通知
func enableForegroundNotification() {
    let center = UNUserNotificationCenter.current()
    center.getNotificationSettings { (settings) in
        if settings.authorizationStatus == .authorized {
            DispatchQueue.main.async {
                UIApplication.shared.registerForRemoteNotifications()
            }
        }
    }
}

// 实现UNUserNotificationCenterDelegate的方法
func userNotificationCenter(_ center: UNUserNotificationCenter, willPresent notification: UNNotification, withCompletionHandler completionHandler: @escaping (UNNotificationPresentationOptions) -> Void) {
    // 在这里处理前台通知的展示方式，例如弹出alert、播放声音等
    completionHandler([.alert, .sound])
}