Question

我试图限制用户First_Name只允许字母，因此在点击send_button后它应该响应数字或特殊字符的错误。我在这里找到了一些例子，但是因为它们是基于较旧的版本而构建的，所以我有问题要使其工作。到目前为止，如果此文本字段中的第一个元素不是字母，但代码允许这样的内容（名字=＆＃34; J123g＆＃34;）或者（例如），我已设法读取名字并抛出错误＆＃34;马克@＃$＆＃34;）并且我不希望这种情况发生。

func isOneLetter(in text: String) -> Bool {
    do {
        let regex = try NSRegularExpression(pattern: "[a-zA-Z]")
        let nsString = text as NSString
        let results = regex.matches(in: text, range: NSRange(location: 0, length: nsString.length))
        let temp = results.map { nsString.substring(with: $0.range)}
        return temp.isEmpty
    } catch let error {
        print("invalid regex: \(error.localizedDescription)")
        return false
    }
}

@IBAction func Send_Button(_ sender: AnyObject) {
    let UserName = First_Name.text
    if (isOneLetter(in: UserName!))
    {
        DisplayMyAlertMessage(userMessage: "First Name must contain only letter and spaces")
    }
}

Answer 1

您的正则表达式模式检查一个字母数字字符，它与两个不需要的示例相匹配。

此正则表达式检查从开头（^）到结尾（$）的字符串必须有一个或更多（+）字母数字字符（[a-zA-Z]）。好处是它将空字符串也视为坏字符。

^[a-zA-Z]+$

Answer 2

另一种方式可能是：

let userInput = ""
let set = CharacterSet(charactersIn: "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLKMNOPQRSTUVWXYZ")
if userInput.rangeOfCharacter(from: set.inverted) != nil {
    print("ERROR: There are numbers included!")
}

Answer 3

首先，您必须自己继承UITextViewDelegate类课

class ViewController: UIViewController, UITextViewDelegate {

第二次添加IBOutlet

@IBOutlet weak var firstName: UITextField!

第三个必须确保该对象正在使用

override func viewDidLoad() {
        super.viewDidLoad()
   firstName.delegate = self
}


func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
    if textField == firstName {
                let allowedCharacters = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"
                let allowedCharacterSet = CharacterSet(charactersIn: allowedCharacters)
                let typedCharacterSet = CharacterSet(charactersIn: string)
                let alphabet = allowedCharacterSet.isSuperset(of: typedCharacterSet)
                return alphabet


      }
  }

Answer 4

更新了swift 3：

如果要验证名称并仅允许用户名字母，则在简单的代码行下使用

//函数定义：

func isValidName(_ nameString: String) -> Bool {

    var returnValue = true
    let mobileRegEx =  "[A-Za-z]{3}"  // {3} -> at least 3 alphabet are compulsory.  

    do {
        let regex = try NSRegularExpression(pattern: mobileRegEx)
        let nsString = nameString as NSString
        let results = regex.matches(in: nameString, range: NSRange(location: 0, length: nsString.length))

        if results.count == 0
        {
            returnValue = false
        }

    } catch let error as NSError {
        print("invalid regex: \(error.localizedDescription)")
        returnValue = false
    }

    return  returnValue
}

//函数调用：

     var firstName = mEnterFirstNameTextField.text!

    let isFirstNameValid = isValidName(firstName)

    if isFirstNameValid{
        // do user logic 
     }else{
        // show error msg: ->  "Enter name is not valid, please enter again..."
     }

仅允许用户名字母

4 个答案: