Creating Camera view as overlay of another view? - ios

Question

I have a QR code scanner viewcontroller, rather than pushing it in a navigation controller i wondered if it was possible to instantiate the view controller to be an overlay on my previous main screen taking up a quarter of the screen, as i dont need it to be a whole separate screen.
It has its own viewcontroller and view, i just need it to overlay at a smaller size.
No code to provide as this is more of a theoretical question

Answer 1

I assume you want to programmatically add a container in which a second UIViewController can be added in in your current UIViewController. See the example on how to achieve this.
import UIKit
class ParentViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
// Set a yellow background color on the parentViewController
self.view.backgroundColor = .yellow
// Create our detailViewController which will be contained in the parent
let detailViewController = DetailViewController()
// Add this detailViewController as a child in the current ParentViewController
addChildViewController(detailViewController)
// Add the detailViewController view as a subview on the ParentViewController
view.addSubview(detailViewController.view)
// Since we dont use IB we disable this property to allow programmatic constraints
detailViewController.view.translatesAutoresizingMaskIntoConstraints = false
// We create the constraints for our detailViewControllers view
NSLayoutConstraint.activate([
detailViewController.view.centerYAnchor.constraint(equalTo: view.centerYAnchor),
detailViewController.view.centerXAnchor.constraint(equalTo: view.centerXAnchor),
detailViewController.view.heightAnchor.constraint(equalToConstant: 200),
detailViewController.view.widthAnchor.constraint(equalToConstant: 200)
])
}
}
class DetailViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
view.backgroundColor = .green
print("DetailViewController loaded!")
}
}
We have a ParentViewController with a simple yellow background. In this controller we add a green DetailViewController as a container. The result is:
When you run this app you'll notice that the console prints the result from the DetailViewController.
If you want to remove the DetailViewController:
// Call this in your ParentViewController
let vc = self.childViewControllers.last
vc?.view.removeFromSuperview()
vc?.removeFromParentViewController()