CODE EXAMPLE FOR SWIFT

swift 5 full screen image viewer

@IBAction func imageTapped(sender: UITapGestureRecognizer) {
    let imageView = sender.view as! UIImageView
    let newImageView = UIImageView(image: imageView.image)
    newImageView.frame = UIScreen.main.bounds
    newImageView.backgroundColor = .blackColor()
    newImageView.contentMode = .ScaleAspectFit
    newImageView.userInteractionEnabled = true
    let tap = UITapGestureRecognizer(target: self, action: "dismissFullscreenImage:")
    newImageView.addGestureRecognizer(tap)
    self.view.addSubview(newImageView)
    self.navigationController?.isNavigationBarHidden = true
    self.tabBarController?.tabBar.isHidden = true
}

func dismissFullscreenImage(sender: UITapGestureRecognizer) {
    self.navigationController?.isNavigationBarHidden = false
    self.tabBarController?.tabBar.isHidden = false
    sender.view?.removeFromSuperview()
}