如何使此功能正常运行

Question

我有2个功能

func checkEmailField() -> Bool {

    if(!loginPasswordTextField.text!.isEmpty){
        return true
    } else {
        print("Empty Field was found")
       // self.displayMessage(error.localizedDescription, fromViewController: self)
        return false

    }

}

和

func displayMessage(errorMessage:String?, fromViewController:UIViewController){

    let titleMessage = "Error"
    let alert = UIAlertController(title: titleMessage, message: errorMessage, preferredStyle: .Alert)
    let actionOK = UIAlertAction(title: "Ok", style: .Default, handler: nil)
    alert.addAction(actionOK)
    fromViewController.presentViewController(alert, animated: true, completion: nil)

}

当我在第一个func（）中取消注释该行时，出现错误未解决的标识符错误...我该如何通过错误使其有效？

Answer 1

因为您没有名为error的变量。 您的displayMessage函数需要一个字符串，因此只需将其传递给一个字符串即可：

func checkEmailField() -> Bool {
    if(!loginPasswordTextField.text!.isEmpty){
        return true
    } else {
        print("Empty Field was found")
        self.displayMessage("Empty field was found", fromViewController: self)
        return false
    }
}