如何使用Swift在文本字段(从右到左)上输入货币格式?

I have a number let’s say 0.00.

我有一个数字假设是0。00。

• When the user taps 1. We should have 0.01
• 当用户点击1。我们应该有0.01
• When the user taps 2. We should display 0.12
• 当用户点击2。我们应该显示0.12
• When the user taps 3. We should display 1.23
• 当用户点击3。我们应该显示1.23
• When the user taps 4. We should display 12.34
• 当用户点击4。我们应该显示12.34

How can I do that with Swift?

我怎么能用斯威夫特做到呢?

6 个解决方案

#1

For Swift 3. Input currency format on a text field (from right to left)

斯威夫特3。在文本字段上输入货币格式(从右到左)

override func viewDidLoad() {
    super.viewDidLoad()

    textField.addTarget(self, action: #selector(myTextFieldDidChange), for: .editingChanged)
}

func myTextFieldDidChange(_ textField: UITextField) {

    if let amountString = textField.text?.currencyInputFormatting() {
        textField.text = amountString
    }
}

extension String {

    // formatting text for currency textField
    func currencyInputFormatting() -> String {

        var number: NSNumber!
        let formatter = NumberFormatter()
        formatter.numberStyle = .currencyAccounting
        formatter.currencySymbol = "$"
        formatter.maximumFractionDigits = 2
        formatter.minimumFractionDigits = 2

        var amountWithPrefix = self

        // remove from String: "$", ".", ","
        let regex = try! NSRegularExpression(pattern: "[^0-9]", options: .caseInsensitive)
        amountWithPrefix = regex.stringByReplacingMatches(in: amountWithPrefix, options: NSRegularExpression.MatchingOptions(rawValue: 0), range: NSMakeRange(0, self.characters.count), withTemplate: "")

        let double = (amountWithPrefix as NSString).doubleValue
        number = NSNumber(value: (double / 100))

        // if first number is 0 or all numbers were deleted
        guard number != 0 as NSNumber else {
            return ""
        }

        return formatter.string(from: number)!
    }
}

#2

You can create a currency text field subclassing UITextField. Add a target for UIControlEvents .editingChanged. Add a selector method to filter the digits from your textfield string. After filtering all non digits from your string you can format again your number using NumberFormatter as follow:

您可以创建一个货币文本字段子类化UITextField。添加UIControlEvents . editingchanged目标。添加一个选择器方法来筛选textfield字符串中的数字。在过滤掉你的字符串的所有非数字之后，你可以使用NumberFormatter格式化你的数字，如下所示:

Xcode 8 Swift 3 or later

Xcode 8 Swift 3或更高

class CurrencyField: UITextField {
    var string: String { return text ?? "" }
    var decimal: Decimal {
        return string.digits.decimal /
        Decimal(pow(10, Double(Formatter.currency.maximumFractionDigits)))
    }
    var decimalNumber: NSDecimalNumber { return decimal.number }
    var doubleValue: Double { return decimalNumber.doubleValue }
    var integerValue: Int { return decimalNumber.intValue   }
    let maximum: Decimal = 999_999_999.99
    private var lastValue: String = ""
    override func willMove(toSuperview newSuperview: UIView?) {
        // you can make it a fixed locale currency if if needed
        // Formatter.currency.locale = Locale(identifier: "pt_BR") // or "en_US", "fr_FR", etc
        addTarget(self, action: #selector(editingChanged), for: .editingChanged)
        keyboardType = .numberPad
        textAlignment = .right
        editingChanged()
    }
    override func deleteBackward() {
       text = string.digits.dropLast().string
       editingChanged()
    }
    func editingChanged() {
        guard decimal <= maximum else {
            text = lastValue
            return
        }
        lastValue = Formatter.currency.string(for: decimal) ?? ""
        text = lastValue
        print("integer:", integerValue)
        print("double:", doubleValue)
        print("decimal:", decimal)
        print("currency:", lastValue)
    }
}

---

extension NumberFormatter {
    convenience init(numberStyle: Style) {
        self.init()
        self.numberStyle = numberStyle
    }
}
extension Formatter {
    static let currency = NumberFormatter(numberStyle: .currency)
}
extension String {
    var digits: [UInt8] { return characters.flatMap{ UInt8(String($0)) } }
    // For Swift 4 or later just remove characters 
    // var digits: [UInt8] { return flatMap{ UInt8(String($0)) } }
}
extension Collection where Iterator.Element == UInt8 {
    var string: String { return map(String.init).joined() }
    var decimal: Decimal { return Decimal(string: string) ?? 0 }
}
extension Decimal {
    var number: NSDecimalNumber { return NSDecimalNumber(decimal: self) }
}

#3

Try this piece of code:

试试这段代码:

struct DotNum {
  private var fraction:String = ""
  private var intval:String = ""
  init() {}
  mutating func enter(s:String) {
    if count(fraction) < 2 {
      fraction = s + fraction
    } else {
      intval = s + intval
    }
  }
  private var sFract:String {
    if count(fraction) == 0 { return "00" }
    if count(fraction) == 1 { return "0\(fraction)" }
    return fraction
  }
  var stringVal:String {
    if intval == ""  { return "0.\(sFract)" }
    return "\(intval).\(sFract)"
  }
}
var val = DotNum()
val.enter("1")
val.stringVal
val.enter("2")
val.stringVal
val.enter("3")
val.stringVal
val.enter("4")
val.stringVal

#4

My final code thanks for your help

我的最终代码谢谢你的帮助

extension Double {
            var twoDigits: Double {
                let nf = NSNumberFormatter()
                nf.numberStyle = NSNumberFormatterStyle.DecimalStyle
                nf.minimumFractionDigits = 2
                nf.maximumFractionDigits = 2
                return self
            }
    }
    var cleanText:String!
            let number:String = sender.currentTitle as String!
            if(amountDisplay.text != nil)
            {
                cleanText = String(Array(amountDisplay.text!).map{String($0)}.filter{ $0.toInt() != nil }.map{Character($0)} ) as String
                cleanText = cleanText + number
            }else{
                cleanText = number
            }

            amount = (Double(cleanText.toInt()!) / 100).twoDigits
            formatter.locale = NSLocale(localeIdentifier: currencies[current_currency_index])
            amountDisplay.text = "\(formatter.stringFromNumber(amount!)!)"

#5

Here is a code for swift 2

这是swift 2的代码

@IBOutlet weak var txtAmount: UITextField!

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

        if string.characters.count == 0 {
            return true
        }

        let userEnteredString = textField.text ?? ""
        var newString = (userEnteredString as NSString).stringByReplacingCharactersInRange(range, withString: string) as NSString
        newString = newString.stringByReplacingOccurrencesOfString(".", withString: "")

        let centAmount : NSInteger = newString.integerValue
        let amount = (Double(centAmount) / 100.0)

        if newString.length < 16 {
            let str = String(format: "%0.2f", arguments: [amount])
            txtAmount.text = str
        }

        return false //return false for exact out put
    }

Note : Connect delegate for textField from storyboard or programatically

注意:从故事板或编程连接textField的委托

#6

Just for fun: copied Thomas's answer (full credits -and points- to him please) into a file to run as a Swift 4.1 script (with minor fixes):

只是为了好玩:把托马斯的答案(请给他满分和点数)拷贝到一个文件中，作为一个Swift 4.1脚本(有小修改)运行:

dotnum.swift:

dotnum.swift:

#!/usr/bin/swift

struct DotNum {
    private var fraction:String = ""
    private var intval:String = ""
    init() {}
    mutating func enter(_ s:String) {
        if fraction.count < 2 {
          fraction = s + fraction
        } else {
          intval = s + intval
        }
    }
    private var sFract:String {
        if fraction.count == 0 { return "00" }
        if fraction.count == 1 { return "0\(fraction)" }
        return fraction
    }
    var stringVal:String {
        if intval == ""  { return "0.\(sFract)" }
        return "\(intval).\(sFract)"
    }
}

var val = DotNum()
val.enter("1")
print(val.stringVal)
val.enter("2")
print(val.stringVal)
val.enter("3")
print(val.stringVal)
val.enter("4")
print(val.stringVal)

Then run it in a terminal:

然后在终端上运行:

$ chmod +x dotnum.swift
$ ./dotnum.swift
0.01
0.21
3.21
43.21