this happened to me too, i saw your answer and i didn't understand it, because that "setPopoverActivity" wasn't recognized. So i started do some changes and this solved just doing the init of the "UIActivityViewController" inside the action void instead on viewDidLoad, where it was at first place.
- (void) flipView {
self.activityViewController =
[[UIActivityViewController alloc] initWithActivityItems:self.dataToShare
applicationActivities: nil];
self.activityViewController.excludedActivityTypes = @[UIActivityTypePrint,UIActivityTypeSaveToCameraRoll,UIActivityTypeAssignToContact, UIActivityTypeAddToReadingList];
[self presentViewController:self.activityViewController animated:YES completion:nil];
}
Hope it helps!