ios - 如何解决 "Method does not override any method from its superclass"错误？

Question

我试图通过“shouldPerformSegueWithIdentifier”覆盖函数进行一种条件转换，它报告错误“方法不覆盖其父类(super class)中的任何方法”并告诉我删除“覆盖”一词。当我这样做时，它会报告下一个错误:

"Method 'shouldPerformSegueWithIdentifier(:sender:)' with Objective-C selector 'shouldPerformSegueWithIdentifier:sender:' conflicts with method 'shouldPerformSegueWithIdentifier(:sender:)' from superclass 'UIViewController' with the same Objective-C selector".

现在这是我的代码:

import UIKit

class ViewController: UIViewController, UITextFieldDelegate {
//MARK: Propierties
@IBOutlet weak var whateverLabel: UILabel!
@IBOutlet weak var errorMessageLabel: UILabel!
@IBOutlet weak var textFieldRandomWord: UITextField!
//MARK: Actions
@IBAction func printWhatever(sender: UIButton) {whateverLabel.text = "Whatever"
    }

@IBOutlet weak var goOnButton: UIButton!

 override func shouldPerformSegueWithIdentifier(identifier: String, sender: UIButton?) -> Bool {
    if identifier == "firstsegue" && sender == goOnButton { // you define it in the storyboard (click on the segue, then Attributes' inspector > Identifier

        if textFieldRandomWord.text == "Whatever" {
            errorMessageLabel.textColor = UIColor .redColor()
            errorMessageLabel.text = "*** NOPE, segue wont occur"
            return false
        }
        else {
            errorMessageLabel.text = "*** YEP, segue will occur"
        }
    }

    // by default, transition
    return true
    }
override func viewDidLoad() {
    super.viewDidLoad()
textFieldRandomWord.delegate = self //ViewController is textFieldRandomWord's delegate, so "self" reffers to itself (ViewController)//
}
//MARK: UITextFieldDelegate
     func textFieldShouldReturn(textField: UITextField) -> Bool {
//Hide the keyboard.
    textFieldRandomWord.resignFirstResponder()
    return true}
func textFieldDidEndEditing(textField: UITextField){
   whateverLabel.text = textFieldRandomWord.text}
//Above, the textFieldShouldReturn function makes the text field inactive when return (enter) is pressed. The last function gets activated automatically when this happens.//
override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}
}

Answer 1

sender 应该是 AnyObject?。你不能改变方法声明中的类型来满足你当前的需要。如果您的 sender 是 UIButton，您必须检查函数内部。