在UITextField中输入时显示验证错误

Question

我创建了一个函数，该函数在UITextField的右侧显示错误，例如电子邮件无效，带有坏字符，我想在用户实时打字时显示错误，而不是在用户完成写作时显示错误，但我似乎无法弄清楚，图像在用户开始再次打字后也不会自行删除，它只是停留在那里。

如果有人知道我如何在用户输入时显示错误，以及如何在显示错误后开始输入时删除它，这将有助于我和未来的swiftians。

代码:

func setPaddingView(strImgname: String,txtField: UITextField){
let imageView = UIImageView(image: UIImage(named: "cross"))
imageView.frame = CGRect(x: 0, y: 0, width: imageView.image!.size.width , height: imageView.image!.size.height)
let paddingView: UIView = UIView.init(frame: CGRect(x: 0, y: 0, width: 50, height: 50))
paddingView.addSubview(imageView)
txtField.rightViewMode = .always
txtField.rightView = paddingView
}

func textFieldDidEndEditing(_ textField: UITextField)
{
if (textField == firstNameFieldSignUp)
{
let name_reg = "[A-Za-z0-9]{2,20}"

let name_test = NSPredicate(format: "SELF MATCHES %@", name_reg)

if name_test.evaluate(with: firstNameFieldSignUp.text) == false
{
self.setPaddingView(strImgname: "cross", txtField: firstNameFieldSignUp)
}
}

if (textField == lastNameFieldSignUp)
{
let name_reg = "[A-Za-z0-9]{3,20}"

let name_test = NSPredicate(format: "SELF MATCHES %@", name_reg)

if name_test.evaluate(with: lastNameFieldSignUp.text) == false
{
self.setPaddingView(strImgname: "cross", txtField: lastNameFieldSignUp)
}
}

Answer 1

@ioslifertextFieldDidEndEditing在textfield结束编辑(辞职)时被调用，将目标添加到viewDidload()上的textfield可能会帮助您获得预期的结果

textField.addTarget(self, action: #selector(textDidChange(_:)), for: .valueChanged)
@objc func textDidChange(_ sender: UITextField) {
// validation logic here
}