Navigation controller delays before pushing to View Controller - ios

Question

I have a View Controller A with a collection view with list of items. I have to push to another View controller B.
When I select an item in Collection View I want this push to occur. But the push happens after a slight delay which I want to avoid.
I have had few lines of code after didSelect Item method and also NavigationController's navigation Bar setup and CollectionView setup in the View Did load and View Will Appear methods of the View Controller B.
I tried removing the codes after CollectionView Did Select just to check if this was causing the delay but the animation is still slow.
View Controller A Code.
DispatchQueue.global(qos: .background).async {
DispatchQueue.main.async {
//write your code here
var dict = projectsArray[indexPath.row - 1] as! [String:Any]
guard let id = dict["_id"] as? NSNumber else{return }
var canvasIds = NSArray()
if let idsAll = projectCanvasIds.object(forKey: id.stringValue) as? NSArray{
canvasIds = idsAll
}
dict["CanvasIds"] = canvasIds
let dict2 = dict as NSDictionary
IndexContentsModel.projectSlectedCanvasIds = dict2.mutableCopy() as! NSMutableDictionary
let vc = IndexCanvasViewController(nibName: "IndexCanvasViewController", bundle: nil)
self.navigationController?.pushViewController(vc, animated: true)
}
}
View Controller B Code
View Did Load has CollectionViewInit() and SetUI()
func collectionViewinit(){
let nib = UINib(nibName: "TopCanvasesCollectionViewCell", bundle: nil)
self.collectionView.register(nib, forCellWithReuseIdentifier: "topCanvasCell")
collectionView.register(UINib(nibName: "CanvasViewCollectionReusableView3", bundle: nil), forSupplementaryViewOfKind: UICollectionElementKindSectionHeader, withReuseIdentifier: "canvasHeaderView")
}
func setUI(){
self.navigationController?.navigationItem.hidesBackButton = true
self.navigationController?.navigationBar.clipsToBounds = true
self.navigationController?.navigationBar.setBackgroundImage(UIImage(), for: .default)
self.navigationController?.navigationBar.shadowImage = UIImage()
let imgView = UIImageView(frame: CGRect(x: 0, y: 0, width: 40, height: 40))
let hostStr = host
let userinfo = UserInfo.shared()
if let photo = userinfo?.dicJSON.object(forKey: "photo") as? String{
let profile = host + photo
imgView.sd_setImage(with: URL(string: profile), completed: nil)
}else{
imgView.image = UIImage(named: "test_Profile")
}
let button = UIButton()
button.addTarget(self, action:#selector(profileViewButtonPressed(_:)), for: UIControlEvents.touchUpInside)
button.frame = CGRect(x: 0, y: 0, width: 36, height: 36)// CGRectMake(0, 0, 36, 36)
button.layer.cornerRadius = button.frame.width / 2
button.layer.masksToBounds = true
button.setImage(imgView.image, for: UIControlState.normal)
// let profileButton = UIBarButtonItem(customView: button)
let searchImage = UIImage(named: "Search_Icon3")!
let notificationImage = UIImage(named: "Notification_Icon3")!
let profileImage = UIImage(named: "test_Profile")!
let backImage = UIImage(named: "Back_Icon3")!
let searchButton = UIBarButtonItem(image: searchImage, style: .plain, target: self, action: #selector(searchViewButtonPressed(_:)))
let notificationButton = UIBarButtonItem(image: notificationImage, style: .plain, target: self, action: #selector(notificationViewButtonPressed(_:)))
let profileButton = UIBarButtonItem(image: profileImage, style: .plain, target: self, action: #selector(profileViewButtonPressed(_:)))
let backButton = UIBarButtonItem(image: backImage, style: .plain, target: self, action: #selector(backButtonPressed(_:)))
self.navigationItem.rightBarButtonItems = [profileButton,notificationButton,searchButton]
self.navigationController?.navigationBar.tintColor = UIColor(hexString: "#373839")
self.navigationItem.leftBarButtonItem = backButton
self.setValues()
}
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(true)
if #available(iOS 11.0, *) {
self.navigationController?.navigationBar.prefersLargeTitles = false
self.navigationController?.navigationItem.largeTitleDisplayMode = .never
self.navigationController!.navigationBar.backgroundColor = UIColor.white
} else {
// Fallback on earlier versions
}
if (self.isBeingPresented || self.isMovingToParentViewController) {
self.collectionView.animateViews(animations: animationsCanvas, reversed: false, initialAlpha: 0, finalAlpha: 1, delay: 0, duration: 0.07, animationInterval: 0.1, completion: nil)
}
}