我有一个号码，比如说0.00。
0.01
0.12
1.23
12.34
我怎样才能用 Swift 做到这一点？
【问题讨论】：
标签： ios swift string uitextfield nsnumberformatter
适用于 Swift 3。在文本字段中输入货币格式（从右到左）
override func viewDidLoad() {
super.viewDidLoad()
textField.addTarget(self, action: #selector(myTextFieldDidChange), for: .editingChanged)
}
@objc 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.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)!
}
}
【讨论】：
$ 符号。并非所有国家/地区的货币都使用两位小数。
您可以创建一个货币文本字段子类 UITextField。为 UIControlEvents .editingChanged 添加一个目标。添加选择器方法以过滤文本字段字符串中的数字。从字符串中过滤出所有非数字后，您可以使用 NumberFormatter 再次格式化您的号码，如下所示：
Xcode 11.5 • Swift 5.2 或更高版本
import UIKit
class CurrencyField: UITextField {
var decimal: Decimal { string.decimal / pow(10, Formatter.currency.maximumFractionDigits) }
var maximum: Decimal = 999_999_999.99
private var lastValue: String?
var locale: Locale = .current {
didSet {
Formatter.currency.locale = locale
sendActions(for: .editingChanged)
}
}
override func willMove(toSuperview newSuperview: UIView?) {
// you can make it a fixed locale currency if needed
// self.locale = Locale(identifier: "pt_BR") // or "en_US", "fr_FR", etc
Formatter.currency.locale = locale
addTarget(self, action: #selector(editingChanged), for: .editingChanged)
keyboardType = .numberPad
textAlignment = .right
sendActions(for: .editingChanged)
}
override func deleteBackward() {
text = string.digits.dropLast().string
// manually send the editingChanged event
sendActions(for: .editingChanged)
}
@objc func editingChanged() {
guard decimal <= maximum else {
text = lastValue
return
}
text = decimal.currency
lastValue = text
}
}
extension CurrencyField {
var doubleValue: Double { (decimal as NSDecimalNumber).doubleValue }
}
extension UITextField {
var string: String { text ?? "" }
}
extension NumberFormatter {
convenience init(numberStyle: Style) {
self.init()
self.numberStyle = numberStyle
}
}
private extension Formatter {
static let currency: NumberFormatter = .init(numberStyle: .currency)
}
extension StringProtocol where Self: RangeReplaceableCollection {
var digits: Self { filter (\.isWholeNumber) }
}
extension String {
var decimal: Decimal { Decimal(string: digits) ?? 0 }
}
extension Decimal {
var currency: String { Formatter.currency.string(for: self) ?? "" }
}
extension LosslessStringConvertible {
var string: String { .init(self) }
}
视图控制器
class ViewController: UIViewController {
@IBOutlet weak var currencyField: CurrencyField!
override func viewDidLoad() {
super.viewDidLoad()
currencyField.addTarget(self, action: #selector(currencyFieldChanged), for: .editingChanged)
currencyField.locale = Locale(identifier: "pt_BR") // or "en_US", "fr_FR", etc
}
@objc func currencyFieldChanged() {
print("currencyField:",currencyField.text!)
print("decimal:", currencyField.decimal)
print("doubleValue:",(currencyField.decimal as NSDecimalNumber).doubleValue, terminator: "\n\n")
}
}
本文的SwiftUI版本here
【讨论】：
let cleanText = String(Array(sender.text).map{String($0)}.filter{ $0.toInt() != nil }.map{Character($0)} ) as NSString。为什么要做出如此复杂的陈述？用临时变量将其分成 3 或 4 块。它使阅读、调试和维护变得更加容易，并且编译器优化了发布版本中的临时变量。
Formatter.currency.locale = Locale(identifier: "es_CL") text = Formatter.currency.string(from:(Double(string.numbers.integer) / 100) as NSNumber) 设置语言环境，但是例如使用此语言环境，文本字段不再起作用？你知道为什么吗？
我从 Leo Dabus 的回答开始（这对我来说不是开箱即用的），并且在尝试简化并使其正常工作的过程中最终得到了这个，如果我认为这是非常精简和干净的自己说吧?
class CurrencyTextField: UITextField {
/// The numbers that have been entered in the text field
private var enteredNumbers = ""
private var didBackspace = false
var locale: Locale = .current
override init(frame: CGRect) {
super.init(frame: frame)
commonInit()
}
required init?(coder: NSCoder) {
super.init(coder: coder)
commonInit()
}
private func commonInit() {
addTarget(self, action: #selector(editingChanged), for: .editingChanged)
}
override func deleteBackward() {
enteredNumbers = String(enteredNumbers.dropLast())
text = enteredNumbers.asCurrency(locale: locale)
// Call super so that the .editingChanged event gets fired, but we need to handle it differently, so we set the `didBackspace` flag first
didBackspace = true
super.deleteBackward()
}
@objc func editingChanged() {
defer {
didBackspace = false
text = enteredNumbers.asCurrency(locale: locale)
}
guard didBackspace == false else { return }
if let lastEnteredCharacter = text?.last, lastEnteredCharacter.isNumber {
enteredNumbers.append(lastEnteredCharacter)
}
}
}
private extension Formatter {
static let currency: NumberFormatter = {
let formatter = NumberFormatter()
formatter.numberStyle = .currency
return formatter
}()
}
private extension String {
func asCurrency(locale: Locale) -> String? {
Formatter.currency.locale = locale
if self.isEmpty {
return Formatter.currency.string(from: NSNumber(value: 0))
} else {
return Formatter.currency.string(from: NSNumber(value: (Double(self) ?? 0) / 100))
}
}
}
【讨论】：
CurrencyTextField 而不是 UITextField
isNumber 也允许使用像“⅚”这样的小数字符。
enteredNumbers.popLast()？
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
【讨论】：
我的最终代码感谢您的帮助
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!)!)"
【讨论】：
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
}
注意：从情节提要或以编程方式连接 textField 的委托
【讨论】：
只是为了好玩：将Thomas's answer（完整的学分 - 并指出 - 给他）复制到一个文件中，以作为 Swift 4.1 脚本运行（有一些小的修复）：
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)
然后在终端中运行它：
$ chmod +x dotnum.swift
$ ./dotnum.swift
0.01
0.21
3.21
43.21
【讨论】：
感谢这里的每一个人。从这里的所有答案中，我设法得出了我的答案。
首先我将 textField 的初始值设置为：
private func commonInit() {
amountTextField.text = "0.00"
}
然后我使用 UITextFieldDelegate 来获取输入值和当前的 textview.text：
func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
//Need to check if the textfield.text can be evaluated as number or not before passing it to the function
//Get the current text value, and current user input and pass it to the
let formattedAmount = formatAmount(oldAmount: textField.text, userInput: string)
textField.text = formattedAmount
return false
}
这里是我的私有函数来格式化数字从右到左移动：
private func formatAmount(currentText: String, userInput: String) -> String {
let amount = currentText.components(separatedBy: ".")
var intValue: String = amount[0]
var decimalValue: String = amount[1]
//backspace registered, need to move the number to the right
if userInput.isEmpty {
decimalValue.remove(at: decimalValue.index(before: decimalValue.endIndex))
decimalValue = intValue.last!.string + decimalValue
intValue.remove(at: intValue.index(before: intValue.endIndex))
if intValue.isEmpty {
intValue = "0"
}
} else {
//Need to consider if user paste value
if userInput.count > 2 {
decimalValue = String(userInput.suffix(2))
intValue = String(userInput.dropLast(2))
} else {
decimalValue = rmAmount[1] + userInput
//Add to int value (move to the right)
intValue = intValue + decimalValue.first!.string
if Int(intValue) == 0 {
intValue = "0" //00 -> 0
} else if intValue.first == "0" {
//remove 0 from at the first position in intValue
intValue.remove(at: intValue.startIndex) //01 -> 1
}
//Remove tenth place from decimal value since it goes to Int already
decimalValue.remove(at: decimalValue.startIndex)
}
}
return intValue + "." + decimalValue
}
基本上就是这样。您可以自己主动添加其他额外的实现。如果我的实现有任何问题，请告诉我。
PS：这当然只适用于某些货币，就我而言，我的应用程序仅针对该本地设置，所以这就是我使用这种方式的原因。
【讨论】：
在对建议的答案进行大量试验和错误之后，我找到了一个非常简单的解决方案：
需要在视图的设置中调用 textField 的设置。
在 switch 语句中，如果用户输入一个介于 0 和 9 之间的数字，则该数字将添加到之前的字符串值中。默认情况下覆盖退格按钮并从字符串中删除最后一个字符。
numberFormatter 的语言环境设置为当前，因此它适用于不同的货币。
func setupTextField() {
textField.delegate = self
textField.tintColor = .clear
textField.keyboardType = .numberPad
}
func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
setFormattedAmount(string)
return false
}
private func setFormattedAmount(_ string: String) {
switch string {
case "0", "1", "2", "3", "4", "5", "6", "7", "8", "9":
amountString = amountString + string
default:
if amountString.count > 0 {
amountString.removeLast()
}
}
let amount = (NSString(string: amountString).doubleValue) / 100
textField.text = formatAmount(amount)
}
private func formatAmount(_ amount: Double) -> String {
let formatter = NumberFormatter()
formatter.numberStyle = .currency
formatter.locale = .current
if let amount = formatter.string(from: NSNumber(value: amount)) {
return amount
}
return ""
}
【讨论】：