动态更改文本字段和标签为货币

Question

对于swift来说，我构建了一个简单的应用程序，包含一个文本域、一个按钮和一个标签。我希望能够在文本框中输入一个数字，并动态地将其更改为货币，即1200更改为$1,200.00。然后，当我按下按钮时，我想让货币乘以一个常数，比如2，并在标签中显示货币金额，就像在文本字段中一样。我似乎无法让这个货币转换器在Swift 3中工作。我的代码非常简单，所以我没有真正展示任何东西，只是寻找一种格式化文本字段和标签答案的方法。

import UIKit
class ViewController: UIViewController,  UIPickerViewDelegate, UIPickerViewDataSource, UITextFieldDelegate {
@IBOutlet var Picker1: UIPickerView!
 var Array = ["1", "2"]
@IBOutlet var grossSalary: UITextField!
@IBOutlet var text: UILabel!
var mult = 2

override func viewDidLoad() {
    super.viewDidLoad()
    // Do any additional setup after loading the view, typically from a nib.
    Picker1.delegate = self
    Picker1.dataSource = self
     grossSalary.delegate = self
     grossSalary.keyboardType = UIKeyboardType.numbersAndPunctuation
    text.text = ""
}
override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}
func pickerView(_ pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String? {
    return Array[row]
}
func pickerView(_ pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
    return Array.count
}
func numberOfComponents(in pickerView: UIPickerView) -> Int{
    return 1
}

@objc(textField:shouldChangeCharactersInRange:replacementString:) func textField(_ grossSalary: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
    let invalidCharacters = CharacterSet(charactersIn: "0123456789.").inverted
    return string.rangeOfCharacter(from: invalidCharacters, options: [], range: string.startIndex ..< string.endIndex) == nil
}
func textFieldShouldReturn(_ textField: UITextField) -> Bool {
    grossSalary.resignFirstResponder()
    return true
}
@IBAction func changetext(_ sender: AnyObject) {
   text.text = grossSalary.text
  //  let result = (text.text.toInt() ?? 0) * 2
  //  text.text = "(result)"
    let a = grossSalary.text
    let b = Int(a!)! * mult
    text.text = ("$(b)0")

}

}

Answer 1

使用Number Formatter()实现结果

//dynamically change to currency formatted text for cash down payment
func myTextFieldDidChange1(_ textField: UITextField) {
    if let amountString1 = cdptext.text?.currencyInputFormatting() {
         cdptext.text = amountString1
    }
}
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)!
  }
}

Answer 2

你可以这样做:

let balance = 125.78
let balanceCurrency = balance.currency
lblBalance.text = balanceCurrency

返回$0.00

extension NumberFormatter {
    convenience init(style: Style) {
        self.init()
        numberStyle = style
    }
}
extension Formatter {
    static let currency = NumberFormatter(style: .currency)
}
extension FloatingPoint {
    var currency: String {
        return Formatter.currency.string(for: self) ?? ""
    }
}