ios - Adding am UIPageViewController in front of a UIViewController -

when app starts first time should display tutorial, screens semitransparent background, in front of first app screen.

i tried creating uipageviewcontroller object, adding view subview of current screen (self.view.addsubview(tutorialviewcontroller.view)) , screen displayed, when swipe uipageviewcontroller not responding event.

class tutorialviewcontroller:uipageviewcontroller, uipageviewcontrollerdatasource { var tutorialsviewcontrollers = [uiviewcontroller]()   override func viewdidload() {     super.viewdidload()     tutorialsviewcontrollers.append(tutorial1viewcontroller())     tutorialsviewcontrollers.append(tutorial2viewcontroller())     tutorialsviewcontrollers.append(tutorial3viewcontroller())     tutorialsviewcontrollers.append(tutorial4viewcontroller())     tutorialsviewcontrollers.append(tutorial5viewcontroller())     self.setviewcontrollers([tutorialsviewcontrollers.first!], direction: .forward, animated: false) { (complete) -> void in     }     self.datasource = self }  func pageviewcontroller(pageviewcontroller: uipageviewcontroller, viewcontrollerbeforeviewcontroller viewcontroller: uiviewcontroller) -> uiviewcontroller? {     if let position = find(self.tutorialsviewcontrollers, viewcontroller)         position > 0     {         return self.tutorialsviewcontrollers[position - 1]     }     return nil } func pageviewcontroller(pageviewcontroller: uipageviewcontroller, viewcontrollerafterviewcontroller viewcontroller: uiviewcontroller) -> uiviewcontroller?{     if let position = find(self.tutorialsviewcontrollers, viewcontroller)         position < self.tutorialsviewcontrollers.count - 1     {         return self.tutorialsviewcontrollers[position - 1]     }     return nil } } 

that's view controller code

let tutorialviewcontroller = tutorialviewcontroller()         self.view.addsubview(tutorialviewcontroller.view) 

did add tutorialviewcontroller child view controller?

self.addchildviewcontroller(tutorialviewcontroller) self.view.addsubview(tutorialviewcontroller.view)