Formatting a UITextField as a price (XXX,XXX.XX)

I've been tearing my hair out trying to find a solution to this.

I simply want a UITextField to correctly format an inputted number as a price. That means only a single decimal point is allowed, two digits after the point (if they were typed in) and a ',' to separate large numbers (eg 150,000).

That is how a price is properly format开发者_运维百科ted, so why is it so difficult to get right?

The closest I've come to a solution is this code. The problem with it, however, is after typing in four digits it reverts to 0?? This is close to a solution, I just can't understand why it does this strange behavior.

You actually don't need any code for this. Just drag a number formatter on your text field in the nib file and configure it to use the "Currency" style.

Via code this would be [myNumberFormatter setNumberStyle:NSNumberFormatterCurrencyStyle]

Beware that the format of prices is very different depending on the locale. In Germany for example, the dot is used as a thousands separator and the comma as the decimal point. Using a style instead of a fixed format takes care of those differences for you.

Hi Here is my solution.

import UIKit


extension Numeric {   // for Swift 3 use FloatingPoint or Int

    func currency(locale: String, symbol: Bool = true) -> String {
        let formatter = NumberFormatter()
        formatter.numberStyle = .currency
        formatter.locale = Locale(identifier: locale)
        if !symbol {
            formatter.currencySymbol = ""
        }
        let result = formatter.string(for: self) ?? ""

        return result
    }

}

ViewController Code

var price: String!
var priceNumber: CGFloat!
@IBOutlet weak var priceInput: UITextField!

ViewDidLoad

priceInput.addTarget(self, action: #selector(priceInputChanged), for: .editingChanged)
priceInput.tintColor = .clear

priceInput.delegate = self

UITextFieldDelegate in Your ViewController

@objc func priceInputChanged(_ textField: UITextField){

    if localIdentifier != nil {
        priceInput.text = priceNumber.currency(locale: localIdentifier, symbol: false)
    }
}
func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {

    if textField.tag == 3 {

        if string.isEmpty {
            if price.count > 0 {
                let last = price.removeLast()
                if last == "." {
                    if price.count > 0 {
                        price.removeLast()
                    }
                }
            }

        }else {
            price.append(string)
        }

        if let input = price {
            let n = NumberFormatter().number(from: input) ?? 0
            priceNumber = CGFloat(truncating: n)

            if localIdentifier != nil {
                priceInput.text = priceNumber.currency(locale: localIdentifier, symbol: false)
            }

        }

    }

    return true
}

That's It