Ios swift – Issue with Flipping Views in UIStackView based on Condition

In my iOS project, I’m working with a UIStackView that contains multiple subviews. I want to dynamically flip or move up and down specific views within the stack view based on a condition. Specifically,

I’m attempting to manipulate the positions of two text fields named FIRST and SECOND. However, I’m encountering an issue where the flipping only works correctly on every second tap or click.

Here is my code for the same

import UIKit
import Combine

import SnapKit

class ViewController: UIViewController {
    
    private var toggleSubject = PassthroughSubject<Bool, Never>()
    private var toggle = false
    private var store = Set<AnyCancellable>()
    
    private lazy var topField: AppTextField = {
        let view = AppTextField(title: "First")
        view.translatesAutoresizingMaskIntoConstraints = false
        return view
    }()
    
    private lazy var bottomField: AppTextField = {
        let view = AppTextField(title: "Second")
        view.translatesAutoresizingMaskIntoConstraints = false
        return view
    }()
    
    private lazy var lineView: UIImageView = {
        let view = UIImageView(frame: .zero)
        view.backgroundColor = .red
        view.translatesAutoresizingMaskIntoConstraints = false
        return view
    }()
    
    private lazy var stackView: UIStackView = {
        let view = UIStackView(arrangedSubviews: [topField, lineView, bottomField, toggleButton])
        view.axis  = .vertical
        view.spacing = 4.0
        view.distribution = .fill
        view.alignment = .fill
        view.translatesAutoresizingMaskIntoConstraints = false
        return view
    }()
    
    private lazy var toggleButton: UIButton = {
        let view = UIButton(frame: .zero)
        view.setTitle("Toggle", for: .normal)
        view.setTitleColor(.white, for: .normal)
        view.setTitleColor(.systemYellow, for: .highlighted)
        view.backgroundColor = .darkGray
        view.translatesAutoresizingMaskIntoConstraints = false
        return view
    }()
    
    
    private lazy var selectedTopFieldLabel: UILabel = {
        let view = UILabel(frame: .zero)
        view.textAlignment = .center
        view.translatesAutoresizingMaskIntoConstraints = false
        return view
    }()
    
    override func viewDidLoad() {
        super.viewDidLoad()
        self.view.addSubview(stackView)
        self.view.addSubview(selectedTopFieldLabel)
        toggleSubject.send(toggle)
        
        stackView.snp.makeConstraints { make in
            make.leading.trailing.centerY.equalToSuperview().inset(16)
        }
        
        lineView.snp.makeConstraints { make in
            make.height.equalTo(0.5)
        }
        
        selectedTopFieldLabel.snp.makeConstraints { make in
            make.top.equalToSuperview().offset(200)
        }
        
        
        toggleButton.addTarget(self, action: #selector(toggleButtonAction), for: .touchUpInside)
        
        toggleSubject.sink { toggle in
            print("---> Changed Toggle",toggle)
            self.updateUI(toggle: toggle)
            UIView.animate(withDuration: 0.25) {
                self.stackView.layoutIfNeeded()
            }
        }.store(in: &store)
        self.updateUI(toggle: toggle)
    }
    
    @objc func toggleButtonAction() {
        toggle.toggle()
        toggleSubject.send(toggle)
    }
    
    private func updateUI(toggle: Bool) {
        let arrangedSubviews = self.stackView.arrangedSubviews
        
        guard var first = arrangedSubviews[0] as? AppTextField,
              var second = arrangedSubviews[2] as? AppTextField else {return}
        stackView.arrangedSubviews.forEach({$0.removeFromSuperview()})
        let changedViews = toggle ? [first, lineView, second, toggleButton] : [second, lineView, first , toggleButton]

        guard let firstTextField = changedViews.first as? AppTextField,
              let firstfieldPlaceholder = firstTextField.placeholder else {return}

        self.selectedTopFieldLabel.text =  "Selected On Top " + " -> " + firstfieldPlaceholder

        changedViews.forEach { view in
            self.stackView.addArrangedSubview(view)
        }
        // Update constraints
        UIView.animate(withDuration: 0.25) {
            self.stackView.setNeedsLayout()
            self.stackView.layoutIfNeeded()
        }
    }
}

class AppTextField: UIView {
    
    private lazy var inputField: UITextField = {
        let textField = UITextField(frame: .zero)
        textField.backgroundColor = .lightGray.withAlphaComponent(0.15)
        textField.translatesAutoresizingMaskIntoConstraints = false
        return textField
    }()
    
    
    var title: String? {
        get { return inputField.placeholder }
        set { inputField.placeholder = newValue }
    }
    
    var placeholder: String? {
        get { return inputField.placeholder }
        set { inputField.placeholder = newValue }
    }
    
    var text: String? {
        get { return inputField.text }
        set { inputField.text = newValue }
    }
    
    init(title: String) {
        super.init(frame: .zero)
        self.title = title
        setupViews()
    }
    
    @available(*, unavailable)
    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    
    private func setupViews() {
        addSubview(inputField)
        inputField.snp.makeConstraints { make in
            make.edges.equalToSuperview()
            make.height.equalTo(48)
        }
    }
}

Thanks in advance.