Question

如何将用户的TextField输入限制为Swift中的数字？

Answer 1

您可以使用UITextFieldDelegate的{{1}}方法来限制用户对数字的输入：

shouldChangeCharactersInRange

针对Swift 3进行了更新：

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

    // Create an `NSCharacterSet` set which includes everything *but* the digits
    let inverseSet = NSCharacterSet(charactersInString:"0123456789").invertedSet

    // At every character in this "inverseSet" contained in the string,
    // split the string up into components which exclude the characters
    // in this inverse set
    let components = string.componentsSeparatedByCharactersInSet(inverseSet)

    // Rejoin these components
    let filtered = components.joinWithSeparator("")  // use join("", components) if you are using Swift 1.2

    // If the original string is equal to the filtered string, i.e. if no
    // inverse characters were present to be eliminated, the input is valid
    // and the statement returns true; else it returns false
    return string == filtered
}

Answer 2

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 = "1234567890"
                let allowedCharacterSet = CharacterSet(charactersIn: allowedCharacters)
                let typedCharacterSet = CharacterSet(charactersIn: string)
                let alphabet = allowedCharacterSet.isSuperset(of: typedCharacterSet)
                let Range = range.length + range.location > (fnameTF.text?.count)!

        if Range == false && alphabet == false {
            return false
        }


        let NewLength = (fnameTF.text?.count)! + string.count - range.length
        return NewLength <= 10


      }
  }

Answer 3

在Swift 4.1和Xcode 10中

将 UITextFieldDelegate 添加到您的班级

class YourViewController: UIViewController, UITextFieldDelegate

然后将此代码写入您的 viewDidLoad（）

yourTF.delegate = self

编写此文本字段委托函数

//MARK - UITextField Delegates
func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
    //For numers
    if textField == yourTF {
        let allowedCharacters = CharacterSet(charactersIn:"0123456789")//Here change this characters based on your requirement
        let characterSet = CharacterSet(charactersIn: string)
        return allowedCharacters.isSuperset(of: characterSet)
    }
    return true
}

Answer 4

对于任何寻求简短答案的人，我发现this非常有用。

func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
    // remove non-numerics and compare with original string
    return string == string.filter("0123456789".contains)
}

在XCode 10.1，Swift 4.2中工作

Answer 5

iOS没有提供这样的功能，你可以指定textfield只接受数字字符。唯一的方法是， UITextFieldDelegate 方法之一，如下所示，

(BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string

您需要实现以下方法并截取输入的字符，并通过以下正则表达式

"^([0-9]+)?(\\.([0-9]{1,2})?)?$"

或

[NSCharacterSet decimalDigitCharacterSet]

您可以查看输入的字符是否为数字，如果匹配正则表达式或字符集，则返回 YES ，否则返回否。

Answer 6

这是可以帮助您的简单解决方案。

将键盘类型更改为数字

您只需将文本字段的键盘类型属性更改为数字键盘这是要更改的属性的屏幕截图

Screen shot

将UITextField输入限制为Swift中的数字

6 个答案:

将键盘类型更改为数字