UI freezing when push ViewController

Question

I have problem to display my ViewControllers. Sometimes happens this... freezing UI while pushing new ViewController. All UI elements created programmatically with SnapKit (in current code CameraUI class).

GIF demo: https://radikal.ru/video/VeDy5trCfNn

Pushing Action from origin ViewController

@objc func cameraAction(){
        let cameraVC = CameraViewController()
        self.navigationController?.pushViewController(cameraVC, animated: true)
    }

CameraViewController

class CameraViewController: UIViewController{
lazy var UI = CameraUI(view: self.view, navController: self.navigationController!)
override func viewDidLoad() {
        super.viewDidLoad()

        title = "Camera"
        addUIElements()
        setupCaptureSession()
        setupDevice()
        setupInputOutput()
        setupPreviewLayer()
        startRunningCaptureSession()
        addActions()
    }
private func addUIElements(){
        UI.addElementsToSuperView()
        view.layoutIfNeeded()
    }
}

score 1 · Answer 1 · answered Jan 13 '19 at 19:22

1

You did not provide a lot of code, but I would venture to suggest that the problem is that you call methods that inhibit the appearance of the screen.

You should try to move some methods for camera setup to viewWillApear or viewDidAppear.

Look at this methods:

        setupCaptureSession()
        setupDevice()
        setupInputOutput()
        setupPreviewLayer()
        startRunningCaptureSession()

answered Jan 13 '19 at 19:22

Vlad Krupenko

361
2
9

Even if i clear all setup you write... problem still the same. – George Heints Jan 13 '19 at 19:23
by the way i have same problem on few controllers. Interesting one thing... i have two controllers with views and collections. All the same, just different content... One works fine (action from Tabbar), the second has same trouble (action from previous controller) – George Heints Jan 13 '19 at 19:26
Maybe you push your controller not from the main thread? @GeorgeHeints – Vlad Krupenko Jan 13 '19 at 19:30
i tried push from DispatchQueue.main.async { push... } Still the same. If you have more ideas.. i will enjoy to listen) – George Heints Jan 13 '19 at 19:34
Did you try this [solution](https://stackoverflow.com/questions/36503224/ios-app-freezes-on-pushviewcontroller) – Vlad Krupenko Jan 13 '19 at 19:38
Okey, I hope this one will help you. Mention me back) – Vlad Krupenko Jan 13 '19 at 19:50

UI freezing when push ViewController

1 Answers1