Styjun

Ive created a navigation which pushes a view controller that contains an image view and a button which adds the same view controller each time the button is tapped. After each tap the memory grows and after each back tap the memory is not released despite deinit being called. There is nothing in the code that points to a memory leak is there something I am missing thank you?

complete project repository

class ViewController: UIViewController 


 lazy var nextButton:UIButton? = 
 let button = UIButton(type: .roundedRect)
 button.setTitle("Next", for: .normal)
 button.addTarget(self, action: #selector(nextButtonTapped), for: .touchUpInside)
 button.translatesAutoresizingMaskIntoConstraints = false
 button.backgroundColor = UIColor.red
 return button
 ()

 lazy var imageView:UIImageView? = 
 let image = #imageLiteral(resourceName: "DJI_0014")
 let imageView = UIImageView(image: image)
 imageView.translatesAutoresizingMaskIntoConstraints = false
 return imageView
 ()

 override func viewDidLoad() 
 super.viewDidLoad()
 // Do any additional setup after loading the view.

 guard let imageView = self.imageView, let nextButton = self.nextButton else
 print("imageView, nextButton are nil")
 return
 

 self.view.backgroundColor = UIColor.white

 self.view.addSubview(imageView)
 NSLayoutConstraint.activate([
 imageView.topAnchor.constraint(equalTo:self.view.topAnchor),
 imageView.leadingAnchor.constraint(equalTo: self.view.leadingAnchor),
 imageView.bottomAnchor.constraint(equalTo: self.view.bottomAnchor),
 imageView.trailingAnchor.constraint(equalTo: self.view.trailingAnchor)])

 view.addSubview(nextButton)
 NSLayoutConstraint.activate([nextButton.centerXAnchor.constraint(equalTo: self.view.centerXAnchor),
 nextButton.centerYAnchor.constraint(equalTo: self.view.centerYAnchor, constant: 0),nextButton.heightAnchor.constraint(equalToConstant: 200),nextButton.widthAnchor.constraint(equalToConstant: 200)])
 

 @objc func nextButtonTapped()
 print("next button tapped")
 self.navigationController?.pushViewController(ViewController(), animated: true)
 

 deinit 
 print("view controller is deinitialized")
 

Ive viewed other questions listed below and tried to adopt their suggestions but none of them seemed to help

Navigation arc memory not released

Memory leak issue in navigation controller

Finally, I have identified the problem, which is from the navigationBar:

` navigationController?.setNavigationBarHidden(true, animated: false)`

This code will remove all the issues on large memory residues. Other parts of codes are fine. and in this situation all memory will keep around 19M all the time.

I tried to use an navigationDelegate to do the transition and found there is a crash overlooked by system and sated that if repeating push vc will make NavigationBar not layout well. So I turn it hidden and the problem has gone. But if you do need navigationBar or its animation, there would be a lot of work to do here.

But the memory issue has been found.