A controller object that presents an activity view controller either modally or in a popover depending on the platform. It associates the created controller object with the activity view controller or popover controller, so that when either are dismissed, all the associations are removed. This way if you hold only a *weak* reference to the retur…

ActivityController.h

#import <UIKit/UIKit.h>
 
@interface ActivityController : NSObject
 
+ (instancetype)presentActivityItems:(NSArray *)activityItems
    		  fromViewController:(UIViewController *)viewController
					   barButtonItem:(UIBarButtonItem *)item;
 
@end

ActivityController.m

#import "ActivityController.h"
#import <objc/runtime.h>
 
void* ActivityControllerContext = &ActivityControllerContext;
 
@interface ActivityController () <UIPopoverControllerDelegate>
@end
 
@implementation ActivityController {
  UIPopoverController *_popoverController;
}
 
+ (instancetype)presentActivityItems:(NSArray *)activityItems
  			  fromViewController:(UIViewController *)viewController
					   barButtonItem:(UIBarButtonItem *)item {
 
	UIActivityViewController *activityViewController = [[UIActivityViewController alloc] initWithActivityItems:activityItems
																						 applicationActivities:nil];
 
	ActivityController *controller = [self new];
 
	if (UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPhone) {
		[viewController presentViewController:activityViewController animated:YES completion:NULL];
		objc_setAssociatedObject(activityViewController, ActivityControllerContext, controller, OBJC_ASSOCIATION_RETAIN);
		return nil;
	}
 
 
	UIPopoverController *popoverController = [[UIPopoverController alloc] initWithContentViewController:activityViewController];
	popoverController.delegate = controller;
	controller->_popoverController = popoverController;
	objc_setAssociatedObject(popoverController, ActivityControllerContext, controller, OBJC_ASSOCIATION_RETAIN);
	[popoverController presentPopoverFromBarButtonItem:item
							  permittedArrowDirections:UIPopoverArrowDirectionAny
											  animated:YES];
	popoverController.passthroughViews = @[];
	return controller;
}
 
- (void)popoverControllerDidDismissPopover:(UIPopoverController *)popoverController {
	_popoverController = nil;
}
 
@end