NSURL *URL = [NSURL fileURLWithPath:[[NSBundle mainBundle] pathForResource:@"empty" ofType:@"pdf"]];
TTOpenInAppActivity *openInAppActivity = [[TTOpenInAppActivity alloc] initWithView:self.view andRect:((UIButton *)sender).frame];
UIActivityViewController *activityViewController = [[UIActivityViewController alloc] initWithActivityItems:@[URL] applicationActivities:@[openInAppActivity]];

if(UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPhone){
    // Store reference to superview (UIActionSheet) to allow dismissal
    openInAppActivity.superViewController = activityViewController;
    // Show UIActivityViewController 
    [self presentViewController:activityViewController animated:YES completion:NULL];
} else {
    // Create pop up
    self.activityPopoverController = [[UIPopoverController alloc] initWithContentViewController:activityViewController];
    // Store reference to superview (UIPopoverController) to allow dismissal
    openInAppActivity.superViewController = self.activityPopoverController;
    // Show UIActivityViewController in popup
    [self.activityPopoverController presentPopoverFromRect:((UIButton *)sender).frame inView:self.view permittedArrowDirections:UIPopoverArrowDirectionAny animated:YES];
}