iOS XIB Localization tips

Localizable.strings

"Welcome_back"="Welcome back";
"PromoCodeAmount"="You have a promo code for %d %@";

StringLocalizableExtension.swift

import Foundation

extension String {
    var localized: String {
        return NSLocalizedString(self, comment: "")
    }
    func getLocalized(arg: CVarArg...) -> String {
        
        return String.init(format: self.localized,arguments: arg)
    }
}

UIButton+Localization.swift

import UIKit

extension UIButton {
    @IBInspectable
     var localizednormalTextKey: String {
         set{
            setTitle(newValue, for: .normal)
         }
         get{
            return titleLabel?.text ?? ""
         }
     }
    
    @IBInspectable
        var localizedSelectedTextKey: String {
            set{
               setTitle(newValue, for: .selected)
            }
            get{
                return titleLabel?.text ?? ""
            }
        }
    
    @IBInspectable
           var localizedDisableTextKey: String {
               set{
                  setTitle(newValue, for: .selected)
               }
               get{
                   return titleLabel?.text ?? ""
               }
           }
}

UILabel+Localization.swift

import UIKit

extension UILabel {
    @IBInspectable
    var localizedTextKey: String {
        set{
            self.text = newValue.localized
        }
        get{
            return text ?? ""
        }
    }
}

UINavigationItem+Localization.swift

import UIKit

extension UINavigationItem {
    @IBInspectable
    var localizedTextKey: String {
        set{
            self.title = newValue.localized
        }
        get{
            return title ?? ""
        }
    }
}

UITextField+Localization.swift

import UIKit

extension UITextField {
    @IBInspectable
    var KeyPlaceholder: String {
        set{
            self.placeholder = newValue.localized
        }
        get{
            return placeholder ?? ""
        }
    }
}