How can I set UIPageViewController (Paging Type) gestures delegate

Question

I have been trying to fix conflicts between UIPageViewControllers's gestures and the ones added on views and UIViewControllers lying inside the page controllers. I simply need to make UIPageViewController a delegate for its gestures how can I do this?

1. I have conformed and implemented the UIGestureDelegate methods in page view, but they are never called.
2. I have also looped to check if gestures exists in UIPageViewControllers gestureRecognizers property. As expected, this array was nil, as mentioned in docs "..Only populated if transition style is 'UIPageViewControllerTransitionStylePageCurl'."
3. I tried fetching the underlying UIScrollView and set its pan gestures delegate to UIPageViewController. Was unable to do so.

How can I set the UIPageViewController gesture's (specifically Pan Gesture) delegate.

Answer 1

This does not set the gesture delegate for the built in Pan gesture of the UIPageViewController but I some how managed to resolve gesture conflicts by fetching the underlying scrollview and then setting a new Pan gesture on the scroll view. This new Pan gesture has the UIPageViewController as its delegate and hence I am able to get calls for the gesture delegate.

-(UIScrollView *)scrollViewInsidePageControl {
    for (UIView * view in self.view.subviews) {
        if([view isKindOfClass:[UIScrollView class]])
            return (UIScrollView *)view;
    }
    return nil;
}

And in -viewDidLoad:

self.internalScrollView = [self scrollViewInsidePageControl];
self.customPanGesture = [UIPanGestureRecognizer new];
self.customPanGesture.delegate = self;
[self.internalScrollView addGestureRecognizer:_customPanGesture];

The above code made calls on the protocol methods for UIGestureRecognizerDelegate on the UIPageViewController instance

-(BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer {
    if(otherGestureRecognizer.view == self.internalScrollView)
        return NO;
    else
        return YES;
}


- (BOOL)gestureRecognizerShouldBegin:(UIGestureRecognizer *)gestureRecognizer
{
    if (gestureRecognizer == _customPanGesture)
    {
        // Did required handling here
    }
    return YES;
}

Answer 2

To set UIPageViewController delegate, simply add "UIPageViewControllerDelegate" and "UIPageViewControllerDataSource" to your UIPageViewController. Then set the delegate and the dataSource of your UIPageViewController to self (the delegate).

class MyPageViewController : UIPageViewController, UIPageViewControllerDelegate, UIPageViewControllerDataSource {
  override func viewDidLoad() {
     super.viewDidLoad()
     self.dataSource = self
     self.delegate = self
   }
}

If you do not set the dataSource, you will not be able to have the UIPageViewController slide gestures between the views.