Why my app is crashing after opening new controller?

Question

This is my image with code

My app is launching and after clicking on new controller crashed. My error is Thread 1: EXC_BAD_ACCESS (code=2, address=0x1d27fc844) Error is in this line NSLayoutConstraint.activate(constants)

 var dimmedBaclroundView : UIView {
    let view = UIView()
    
    view.translatesAutoresizingMaskIntoConstraints = false
    view.backgroundColor = UIColor.black.withAlphaComponent(0.3)
    return view
}

lazy var CView = CustomView { [weak self] in
    guard let self = self else {return}
    self.dismiss(animated: true, completion:  nil)
    
}

init() {
    super.init(nibName: nil, bundle: nil)
    modalPresentationStyle = .overCurrentContext
    modalTransitionStyle = .crossDissolve
    
}

required init?(coder:NSCoder) {
    fatalError("init(coder :) has not been implanted")
}



override func viewDidLoad() {
    super.viewDidLoad()

    view.addSubview(dimmedBaclroundView)
    view.addSubview(CView)
    
    
    var constants = [
        dimmedBaclroundView.leadingAnchor.constraint(equalTo: view.leadingAnchor),
        dimmedBaclroundView.trailingAnchor.constraint(equalTo: view.trailingAnchor),
        dimmedBaclroundView.topAnchor.constraint(equalTo: view.topAnchor),
        dimmedBaclroundView.bottomAnchor.constraint(equalTo: view.bottomAnchor)
    ]
    
    constants.append(contentsOf: [
        CView.leadingAnchor.constraint(equalTo: view.readableContentGuide.leadingAnchor),
        CView.trailingAnchor.constraint(equalTo: view.readableContentGuide.trailingAnchor),
        CView.centerYAnchor.constraint(equalTo: view.centerYAnchor, constant: 10),
        CView.heightAnchor.constraint(equalTo: view.heightAnchor, constant: 0.3)
    ])
    
    NSLayoutConstraint.activate(constants) //Here is my error
}

Answer 1

Your view should not be a computed property, you should only initialize it once when viewcontroller initialize, like this:

var dimmedBaclroundView : UIView = {
    let view = UIView()
    
    view.translatesAutoresizingMaskIntoConstraints = false
    view.backgroundColor = UIColor.black.withAlphaComponent(0.3)
    return view
}()

Crashing happen probably because it cannot find the previous instance of dimmedBaclroundView because it got created again after every call, also you should fix the name..