let storyboard = UIStoryboard(name: "Main", bundle: nil)
let firstViewController = storyboard.instantiateViewController(withIdentifier: "FirstViewController")
let secondViewController = storyboard.instantiateViewController(withIdentifier: "SecondViewController")
let thirdViewController = storyboard.instantiateViewController(withIdentifier: "FirstViewController")
let fourViewController = storyboard.instantiateViewController(withIdentifier: "SecondViewController")
// Initialize a FixedPagingViewController and pass
// in the view controllers.
let pagingViewController = PagingViewController(viewControllers: [
firstViewController,
secondViewController,
thirdViewController, fourViewController
])
// Make sure you add the PagingViewController as a child view
// controller and constrain it to the edges of the view.
addChild(pagingViewController)
view.addSubview(pagingViewController.view)
view.constrainToEdges(pagingViewController.view)
pagingViewController.didMove(toParent: self)