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'类型'通知。名称'没有成员'UITextField'

swift4.2 nsnotificationcenter ios

7

Krunal · 技术社区 · 6 年前

在swift4.2中,出现以下错误,这在swift4中运行良好。

'类型'通知。名称'没有成员'UITextField'

NotificationCenter.default.addObserver(forName: NSNotification.Name.UITextField.textDidChangeNotification, object: textField, queue: OperationQueue.main) { (notification) in
            loginAction.isEnabled = textField.text != ""
        }

完整代码:

@IBAction func alertWithLogin(){

    let alertController = UIAlertController(title: "Please Enter Credential", message: nil, preferredStyle: .alert)

    // ADD ACTIONS HANDLER
    let loginAction = UIAlertAction(title: "Login", style: .default) { (_) in

        let loginTextField = alertController.textFields![0] as UITextField
        let passwordTextField = alertController.textFields![1] as UITextField

        // do something with after login
    }
    loginAction.isEnabled = false
    alertController.addAction(loginAction)

    let cancelAction = UIAlertAction(title: "Cancel", style: .cancel) { (_) in
        // do something
    }
    alertController.addAction(cancelAction)

    // ADD TEXT FIELDS
    alertController.addTextField { (textField) in
        textField.placeholder = "Email"
    }
    alertController.addTextField { (textField) in
        textField.placeholder = "Password"
        textField.isSecureTextEntry = true

        // enable login button when password is entered
        NotificationCenter.default.addObserver(forName: NSNotification.Name.UITextField.textDidChangeNotification, object: textField, queue: OperationQueue.main) { (notification) in
            loginAction.isEnabled = textField.text != ""
        }
    }

    // PRESENT
    present(alertController, animated: true)
}

3 回复 | 直到 6 年前

1

48

rmaddy 6 年前

textDidChangeNotification 是…的成员 UITextField (和 UITextView

NotificationCenter.default.addObserver(
    self,
    selector: #selector(self.keyboardDidShow(notification:)),
    name: UITextField.textDidChangeNotification,
    object: nil)

2

4

iHarshil l0gg3r 5 年前

我也面临同样的问题,

下面是最简单的解决方案:

forName: NSNotification.Name.UITextField.textDidChangeNotification

像这样用在 forName: 参数:

NotificationCenter.default.addObserver(forName: UITextField.textDidChangeNotification, object: textField, queue: OperationQueue.main) { (notification) in
//Your code goes here...
        }

3

1

Sven Shao 6 年前

        NotificationCenter.default.addObserver(forName: Notification.Name.UITextFieldTextDidChange, object: textField, queue: OperationQueue.main) { (notification) in
            //...
    }

在swift sdk中,所有通知名称都应该是struct:通知。名称