Question

我只是试图检测用户何时开始在UITextField中输入文本。我在这里阅读了几篇文章，这些文章指示我链接UITextField，然后设置我的文本字段委托，最后实现必要的方法。我已经完成了所有这些工作，但是启动我的代码后，什么也没有显示。我们将不胜感激。

class ViewController: UIViewController, UITextFieldDelegate {

    @IBOutlet weak var button: UIButton!

    @IBOutlet weak var textField: UITextField!


    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.
        button.isEnabled = false
        textField.delegate = self






    }


    func textFieldDidBeginEditing(textField: UITextField) {

        print("TextField did begin editing method called")
    }

    func textFieldDidEndEditing(textField: UITextField) {

        print("TextField did end editing method called\(textField.text)")
    }

    func textFieldShouldBeginEditing(textField: UITextField) -> Bool {

        print("TextField should begin editing method called")
        return true;
    }

    func textFieldShouldClear(textField: UITextField) -> Bool {

        print("TextField should clear method called")
        return true;
    }

    func textFieldShouldEndEditing(textField: UITextField) -> Bool {
        print("TextField should end editing method called")
        return true;
    }


    func textField(textField: UITextField, shouldChangeCharactersInRange range: NSRange, replacementString string: String) -> Bool {
        print("While entering the characters this method gets called")
        return true;
    }


    func textFieldShouldReturn(textField: UITextField) -> Bool {

        print("TextField should return method called")
        textField.resignFirstResponder();
        return true;
    }




}

Answer 1

正如rmaddy所述，您的方法签名错误。我认为您会收到类似“实例方法'textFieldDidEndEditing（textField :)'与协议'UITextFieldDelegate'的可选要求'textFieldDidEndEditing'几乎匹配”的警告。您应该具有以下方法：

func textFieldDidBeginEditing(_ textField: UITextField) {

    print("TextField did begin editing method called")
}

func textFieldDidEndEditing(_ textField: UITextField) {

    print("TextField did end editing method called\(textField.text)")
}

func textFieldShouldBeginEditing(_ textField: UITextField) -> Bool {

    print("TextField should begin editing method called")
    return true;
}

func textFieldShouldClear(_ textField: UITextField) -> Bool {

    print("TextField should clear method called")
    return true;
}

func textFieldShouldEndEditing(_ textField: UITextField) -> Bool {
    print("TextField should end editing method called")
    return true;
}


func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
    print("While entering the characters this method gets called")
    return true;
}


func textFieldShouldReturn(_ textField: UITextField) -> Bool {

    print("TextField should return method called")
    textField.resignFirstResponder();
    return true;
}

为什么不调用我的UITextField Delegate方法？

1 个答案: