以编程方式返回上一页

Question

enter image description here I am making a user login page for my IOS App. I am trying to make everything programmatically without using a segue in the main story board. I have managed to go to the next page as you can see in the code and create a custom left back bar item. But I don't know how to go back to the first page when I click on that button. I have attached the screen shot of my story board and app below. Can you please tell me how I can go back to the first page by clicking the X button? Here is my code:

import UIKit

class FirstPage: UIViewController {

let hgt = UIScreen.main.bounds.height/2


private let loginSignup: UIButton = {
    let button = UIButton(type: .system)
    button.setTitle("Login or Sign Up", for: .normal)
    button.translatesAutoresizingMaskIntoConstraints = false
    button.titleLabel?.font = UIFont.boldSystemFont(ofSize: 20)
    button.setTitleColor(.green, for: .normal)
    button.addTarget(self, action: #selector(loginSignupBtn), for: .touchUpInside)
    return button
}()

@objc private func loginSignupBtn() {
    let vc = self.storyboard!.instantiateViewController(withIdentifier: "Login") as! Login
    vc.loadViewIfNeeded()
    self.navigationController?.pushViewController(vc, animated: true)
    self.navigationController?.isNavigationBarHidden = false
    let backItem = UIBarButtonItem(title: "X ", style: UIBarButtonItem.Style.done, target: nil, action: nil)
    let font = UIFont.boldSystemFont(ofSize: 26)
    backItem.setTitleTextAttributes([NSAttributedString.Key.font:font] ,for: .normal)
    backItem.tintColor = UIColor.green
    vc.navigationItem.leftBarButtonItem = backItem
}
override func viewDidLoad() {
    super.viewDidLoad()
    setupLayout()
}
override func viewWillAppear(_ animated: Bool) {

}
private func setupLayout() {
    let topImageContainerView = UIView()
    //topImageContainerView.backgroundColor = .yellow
    view.addSubview(topImageContainerView)
    //enable auto layout
    topImageContainerView.translatesAutoresizingMaskIntoConstraints = false
    topImageContainerView.topAnchor.constraint(equalTo: view.topAnchor).isActive = true
    topImageContainerView.leadingAnchor.constraint(equalTo: view.leadingAnchor).isActive = true
    topImageContainerView.trailingAnchor.constraint(equalTo: view.trailingAnchor).isActive = true
    topImageContainerView.heightAnchor.constraint(equalTo: view.heightAnchor, multiplier: 0.5).isActive = true
    view.addSubview(loginSignup)
    loginSignup.translatesAutoresizingMaskIntoConstraints = false
    loginSignup.topAnchor.constraint(equalTo: view.topAnchor,constant:hgt/2).isActive = true
    loginSignup.leadingAnchor.constraint(equalTo: view.leadingAnchor).isActive = true
    loginSignup.trailingAnchor.constraint(equalTo: view.trailingAnchor).isActive = true
    loginSignup.heightAnchor.constraint(equalTo: view.heightAnchor, multiplier: 0.5).isActive = true

}

}

enter image description here

Answer 1

Here you need to add target and selector for when the x button is clicked

let backItem = UIBarButtonItem(title: "X ", 
  style: UIBarButtonItem.Style.done,
   target: self, action:#selector(goBack))

---

@objc func goBack(_ bar:UIBarButtonItem) {
   self.navigationController?.popToRootViewController(animated:true)
}