如何使用 Swift 在文本字段(从右到左)上输入货币格式? [英] How to input currency format on a text field (from right to left) using Swift?

问题描述

我有一个数字，比如说 0.00.

I have a number let’s say 0.00.

• 当用户点击 1. 我们应该有 0.01
• 当用户点击 2. 我们应该显示 0.12
• 当用户点击 3. 我们应该显示 1.23
• 当用户点击 4. 我们应该显示 12.34

我如何使用 Swift 做到这一点?

How can I do that with Swift?

推荐答案

对于 Swift 3.在文本字段上输入货币格式(从右到左)

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

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)!
    }
}

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