OTP Pin code view, hidden text field and enter single digit in each text field

PinStackView.swift

import SwiftUI
import Introspect

/**
Used like this:

PinStackView { pin, success in
	self.passCodeFilled = success
}

*/

struct PinStackView: View {
	
	var maxDigits = 6
	
	@State var pin = ""
	
	// String is the pin code, bool is completed or not
	var handler: ((String, Bool) -> Void)
	
	func getPinNumber(_ index: Int) -> String {
		
		let pin = Array(self.pin)
		
		if pin.indices.contains(index), !String(pin[index]).isEmpty {
			return String(pin[index])
		}
		
		return "0"
	}
	
	var body: some View {
		ZStack {
			backgroundField
			HStack {
				ForEach(0..<maxDigits) { digit in
					Text(self.getPinNumber(digit)).padding().background(Color(.systemFill))
				}
			}

		}
	}
	
	private var backgroundField: some View {
		let boundPin = Binding<String>(get: { self.pin }, set: { newValue in
			self.pin = newValue
			
			if newValue.count == self.maxDigits {
				self.closeKeyboard()
			}
			
			self.handler(newValue, newValue.count == self.maxDigits)
		})

		return TextField("", text: boundPin).introspectTextField { textField in
			textField.becomeFirstResponder()
			textField.isHidden = true
		}
		.keyboardType(.numberPad)
	}
	
	private func closeKeyboard() {
		UIApplication.shared.endEditing() // Closing keyboard does not exist for swiftui yet
	}
}

struct PinStackView_Previews: PreviewProvider {
	static var previews: some View {
		PinStackView { pin, success in
			print(pin)
		}
	}
}

extension UIApplication {
	func endEditing() {
		sendAction(#selector(UIResponder.resignFirstResponder), to: nil, from: nil, for: nil)
	}
}