如何检查UITextField的值以确定特定类型的字符，例如字母或数字?

What I want to do is set some boolean in the if statement below to true if anything other than letters, numbers, dashes and spaces is contained in the textField.

我要做的是将下面if语句中的一些布尔值设置为true，如果textField中包含除字母、数字、破折号和空格之外的任何内容。

Then for an email field check for a valid email.

然后在电子邮件字段中检查有效的电子邮件。

This is how I'm checking for length:

这就是我检查长度的方法:

    if countElements(textField.text!) < 2 || countElements(textField.text) > 15 {
        errorLabel.text = "Name must have between 2 and 15 characters."
        self.signUpView.signUpButton.enabled = false
    } else {
        errorLabel.text = ""
        self.signUpView.signUpButton.enabled = true
    }

This if statement is inside the UITextFieldDelegate method textFielddidEndEditing. I have a feeling I'll have to use some form of regex to check for a valid email.

这个if语句位于UITextFieldDelegate方法textFielddidEndEditing中。我有一种感觉，我必须使用某种形式的regex来检查有效的电子邮件。

Would it make sense to use a regex to check a field only contains the characters I allow and return a boolean that'll tell me if the text field contains disallowed characters so I can then show an error message.

使用regex检查字段是否只包含我允许的字符，并返回一个布尔值，该布尔值将告诉我文本字段是否包含不允许的字符，以便我可以显示错误消息。

Is there some preferred way to do this? In objective-c I used NSCharacterSet but not sure how to implement that here.

有什么更好的方法吗?在objective-c中，我使用了ns字符集但不确定如何在这里实现。

Thanks for your time

谢谢你的时间

1 个解决方案

#1

This is how I done it in the end.

最后我就是这么做的。

    override func textFieldDidEndEditing(textField: UITextField) {

        let usernameField = self.signUpView.usernameField.text as NSString
        let alphaNumericSet = NSCharacterSet.alphanumericCharacterSet()
        let invalidCharacterSet = alphaNumericSet.invertedSet
        let rangeOfInvalidCharacters = usernameField.rangeOfCharacterFromSet(invalidCharacterSet)
        let userHasNameInvalidChars = rangeOfInvalidCharacters.location != NSNotFound

        if textField == self.signUpView.usernameField {

            if userHasNameInvalidChars {
                errorLabel.text = "Letters and numbers only please!"
                self.signUpView.signUpButton.enabled = false
                // do more error stuff here
            } else {
                self.signUpView.signUpButton.enabled = true
            }
         }
     }

Thanks to the blog post: http://toddgrooms.com/2014/06/18/unintuitive-swift/

谢谢你的博客:http://toddgrooms.com/2014/06/18/un- swift/。

#1