ios – 在swift中验证失败时,在UITextField中自动显示错误图标

我希望错误图标图像将在UITextField中自动显示,其中一个验证在 swift中失败.

这是正常的阶段

验证失败时,这是错误阶段

对于那个UITextField,我创建了自定义UITextField,如下所示

class ovalTextField: UITextField {

    required init(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)!
        createBorder()
    }

    required override init(frame: CGRect) {
        super.init(frame: frame)
        createBorder()
    }

    func createBorder(){

        let errorImg = UIImageView (frame: CGRectMake(0,30,30))
        errorImg.image = UIImage(named: "error")
        errorImg.contentMode = UIViewContentMode.Left

        self.layer.borderWidth = 1.0
        self.layer.borderColor = UIColor(red:0.93,green:0.93,blue:0.93,alpha:1.0).CGColor
        self.layer.cornerRadius = self.frame.size.height / 2
        self.layer.masksToBounds = true

        let gapLabel = UIView (frame: CGRectMake(60,10,40))
        self.leftView = gapLabel
        self.leftviewmode = UITextFieldviewmode.Always

        /* display that one when validation is Failed */
        self.rightView = errorImg;
        self.rightviewmode = UITextFieldviewmode.Always
    }
}

并在ViewController中使用了UITextField,

@IBOutlet var txtEmail: ovalTextField!

如果该txtEmail为空或无效的电子邮件地址,我想显示错误图标消息.

请建议我怎么做.提前致谢.

解决方法

您可以使用UITextFiledDelegate方法func textField(textField：UITextField,shouldChangeCharactersInRange range：NSRange,replacementString string：String) – > Bool在用户输入时验证电子邮件.

>首先设置委托,txtEmail.delegate = self,然后
>实现委托方法

func textField(textField: UITextField,shouldChangeCharactersInRange  range: NSRange,replacementString string: String) -> Bool {

    let email = (textField.text! as Nsstring).stringByReplacingCharactersInRange(range,withString: string)

    if /* email is validate */ {
        textField.rightView?.hidden = false
    } else {
        textField.rightView?.hidden = true
    }

    return true

}