未调用通知观察者选择器

Question

我有这个观察者

    override func viewDidLoad() {
        super.viewDidLoad()
        NotificationCenter.default.addObserver(self, selector: #selector(GetUserID(_:)), name: Notification.Name("UserID"), object: nil)
    }

和这个选择器功能

    @objc func GetUserID(_ notification: Notification){
        let User = notification.object as? String
        self.UserID = User
    }

而且我一直在 UserID 中获得 nil，即使我确定当我收到通知时它不是 nil 这让我相信选择器没有被调用

Answer 1

您可以通过以下方法获得观察者值

 let selectedIndex:[String: Int] = ["selectedIndex": 1]
                         //selectedindex = 0
                         // post a notification
            NotificationCenter.default.post(name: NSNotification.Name(rawValue: "SelectedSegment"), object: nil, userInfo: selectedIndex)



    NotificationCenter.default.addObserver(self, selector: #selector(self.changeSegmentControlIndex(notification:)), name: Notification.Name("SelectedSegment"), object: nil)

     @objc func changeSegmentControlIndex(notification: Notification) {
        
        if let selectedIndex = notification.userInfo?["selectedIndex"] as? Int {
         // do something with your image
            print(selectedIndex)

         }
    }