Content pushed down in a UIPageViewController with UINavigationController

Question

UPDATE 2

I\'ve been running and testing my app in the iOS Simulator using a 4-inch device. If I run using a 3.5-inch device the label doesn\'t jump.

Answer 1

As @djibouti33 already posted:

a pageViewController couldn't properly lay out it's child view controller initially if it contained a scroll view. by the time we're in layoutSubviews, pageViewController seems to have gotten it's bearings and everything is laid out just fine

By waiting for layoutSubViews to load before setting any viewControllers to the UIPageViewController was the only thing that worked for me.

override func viewDidLoad() {
    super.viewDidLoad()
    self.pageViewController = self.storyboard?.instantiateViewController(withIdentifier: "yourPageViewController") as? UIPageViewController       
    self.pageViewController?.dataSource = self

    pageViewController?.automaticallyAdjustsScrollViewInsets = false    
    self.pageViewController?.view.frame = CGRect(x: 0, y: 0, width: view.frame.size.width, height: view.frame.height)       
    self.addChildViewController(self.pageViewController!)        
    self.view.addSubview((self.pageViewController?.view)!)       
    self.pageViewController?.didMove(toParentViewController: self)
}


override func viewDidLayoutSubviews() {
    let startVC = self.viewControllerAtIndex(index: 0) as infoDataViewController     
    let viewControllers = NSArray(object: startVC)    
    self.pageViewController?.setViewControllers(viewControllers as? [UIViewController], direction: .forward, animated: true, completion: nil)
}