NSNumberFormatter分组

Question

我想用数字格式化字符串，如下所示：XX XX XX (例如，12 34 56)

我使用NSNumberFormatter和分组分隔符：

let formatter = NSNumberFormatter()
formatter.usesGroupingSeparator = true
formatter.groupingSize = 2
formatter.groupingSeparator = " "
if let number = Int(theText.stringByReplacingOccurrencesOfString(" ", withString: "")) {
       let numberToFormat = NSNumber(integer:number)
       textField.text = formatter.stringFromNumber(numberToFormat)
}

如果输入数字123456，这将很好--它被格式化为12 34 56。

我在shouldChangeCharactersInRange方法中使用这个方法，所以它应该在键入时格式化数字。分组分隔符定义的数字是从右侧按groupingSize值分组的，所以当您键入123456时，文本是如何改变的：

1
12
1 23
12 34
1 23 45
12 34 45

我想把它格式化如下：

1
12
12 3
12 34
12 34 5
12 34 56

是否可以从哪一方定义分隔符组号？

Answer 1

不确定如果你必须要隐藏到Int，在结尾添加一个"0“怎么样？然后删除最后一个"0“。

let formatter = NSNumberFormatter()
formatter.usesGroupingSeparator = true
formatter.groupingSize = 2
formatter.groupingSeparator = " "

var str = "12345"
if str.characters.count % 2 != 0 {
    str += "0"
}
if let number = Int(str.stringByReplacingOccurrencesOfString(" ", withString: "")) {
    let numberToFormat = NSNumber(integer:number)
    formatter.stringFromNumber(numberToFormat)
}

另一种解决办法是：

let string = "12345"

var results = [String]()
for index in 0 ..< string.characters.count-1 {
    if index % 2 == 0 {
        let range = NSRange(location: index, length: 2)
        results.append((string as NSString).substringWithRange(range))
    }
}

if string.characters.count % 2 != 0 {
    let last = (string as NSString).substringFromIndex(string.characters.count-1)
    results.append(last)
}

Answer 2

Swit 4

您必须使用UITextField：func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String)的委托

这样做很好：

 func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
    if textField == YourTextField {
        if (textField.text?.count)! < 8 {
            let formatter = NumberFormatter()
            formatter.usesGroupingSeparator = true
            formatter.locale = NSLocale(localeIdentifier: "en_GB") as Locale?
            formatter.groupingSize = 2
            formatter.groupingSeparator = "-" // if you want the format XX-XX-XX
            // Uses the grouping separator corresponding
            if let groupingSeparator = formatter.groupingSeparator {

                if string == groupingSeparator {
                    return true
                }
                if let textWithoutGroupingSeparator = textField.text?.replacingOccurrences(of: groupingSeparator, with: "") {
                    var totalTextWithoutGroupingSeparators = textWithoutGroupingSeparator + string
                    if string == "" { // pressed Backspace key
                        totalTextWithoutGroupingSeparators.characters.removeLast()
                    }
                    if let numberWithoutGroupingSeparator = formatter.number(from: totalTextWithoutGroupingSeparators),
                        let formattedText = formatter.string(from: numberWithoutGroupingSeparator) {
                        print(numberWithoutGroupingSeparator)
                        numberWithoutGroupingSeparators = String(format: "%@", numberWithoutGroupingSeparator)
                        textField.text = formattedText
                        return false
                    }
                }
            }
            return true
        }
    }
        return true

}