swift - 我收到错误 "unrecognized selector sent to instance"

Question

当我尝试按下计算器上的任何按钮时，它给我错误 unrecognized selector sent to instance 0x7f7f85e04e40 我将这段代码从 Swift 2 更新到 Swift 4 但当时它曾经工作。代码有什么问题？

import UIKit

class Valuta: UIViewController {
    @IBOutlet weak var euro: UILabel!
    @IBOutlet weak var zloty: UILabel!
    @IBOutlet weak var topButton: UIButton!
    @IBOutlet weak var bottomButton: UIButton!
    var valutas : [ValutaWaarde] = []

    var number = 0;
    var isTypingNumber = false
    var currentNumber = 0;
    var currency = "PLN";

    @IBAction func numberTapped(sender: AnyObject) {
        let number = sender.currentTitle!
        var disable = false

        if number == "."{
            if euro.text!.range(of: ".") != nil{
                disable = true
            }
        }

        if(disable == false){
            if isTypingNumber {
                euro.text = euro.text!+number!
            } else {
                euro.text = number
                isTypingNumber = true
            }



            var output : Float;
            if(currency == "EUR"){
                output = (euro.text! as NSString).floatValue*Float((valutas[0].rates?.pLN!)!)
            }
            else{
                output = (euro.text! as NSString).floatValue/Float((valutas[0].rates?.pLN!)!)
            }

            zloty.text = String(format: "%.2f", output)
        }
    }

    @IBAction func resetCalculator(sender: AnyObject) {
        isTypingNumber = false;
        zloty.text = "0";
        euro.text = "0";
    }

    override func viewDidLoad() {
     super.viewDidLoad()
     UINavigationBar.appearance().isTranslucent = false;
     UINavigationBar.appearance().barTintColor = UIColor(red: CGFloat(51/255.0), green: 51/255, blue: 51/255, alpha: 1)
     UINavigationBar.appearance().titleTextAttributes = [NSAttributedStringKey.foregroundColor:UIColor.white]

     //Get list
     let url = URL(string: "https://api.fixer.io/latest?symbols=PLN&base=EUR")
     var request = NSMutableURLRequest(url: url! as URL, cachePolicy: NSURLRequest.CachePolicy.returnCacheDataElseLoad, timeoutInterval: Double.infinity)
     if Reachability.isConnectedToNetwork(){
        request = NSMutableURLRequest(url: url! as URL, cachePolicy: NSURLRequest.CachePolicy.useProtocolCachePolicy, timeoutInterval: Double.infinity);
     }
     let session = URLSession.shared

     let task = session.dataTask(with: request as URLRequest,
                                completionHandler: { data, response, error -> Void in
                                    do {
                                        if let json = try JSONSerialization.jsonObject(with: data!) as? [[String: String]] {
                                            for valutaData in json {
                                                let valuta = ValutaWaarde(dictionary: valutaData as NSDictionary)
                                                self.valutas.append(valuta!)
                                            }
                                        }
                                    } catch { print(error) }
     })
     task.resume()
    }

    ...
}

Answer 1

尝试在 Storyboard中重新连接 @IBOutlet 和 @IBAction。