Question

我正在努力用Swift 3做这个。我有一个文本字段，我想限制只有数字和一个小数点和小数点后的两个字符。我还想让它在输入非整数时不使用小数点的区域中工作。谢谢你的任何建议！

Answer 1

您需要将委托分配给您的文本字段，并在shouldChangeCharactersIn委托方法中进行验证：

使用字符串验证方法添加扩展名：

extension String{

    private static let decimalFormatter:NumberFormatter = {
        let formatter = NumberFormatter()
        formatter.allowsFloats = true
        return formatter
    }()

    private var decimalSeparator:String{
        return String.decimalFormatter.decimalSeparator ?? "."
    }

    func isValidDecimal(maximumFractionDigits:Int)->Bool{

        // Depends on you if you consider empty string as valid number
        guard self.isEmpty == false else {
            return true
        }

        // Check if valid decimal
        if let _ = String.decimalFormatter.number(from: self){

            // Get fraction digits part using separator
            let numberComponents = self.components(separatedBy: decimalSeparator)
            let fractionDigits = numberComponents.count == 2 ? numberComponents.last ?? "" : ""
            return fractionDigits.characters.count <= maximumFractionDigits
        }

        return false
    }

}

在您的委托方法中：

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

    // Get text
    let currentText = textField.text ?? ""
    let replacementText = (currentText as NSString).replacingCharacters(in: range, with: string)

    // Validate
    return replacementText.isValidDecimal(maximumFractionDigits: 2)

}

Answer 2

 var number = Double(yourTextfield.text)
 if number != nil {
   //if user enters more than 2 digits after the decimal point it will round it up to 2
   let roundedNumber = Double(num!).roundTo(places: 2)  
 }
 else {
//probably print an error message
}

将文本字段限制为一个小数点输入，仅限数字，以及小数位后的两个字符 - Swift 3

2 个答案: