UIActivityViewController completion handler still invokes activity even if user clicks on cancel

This is really annoying! Completed always returns yes, even if the user cancels the share option. eg I click on sharebook share and not share, just click Cancel. Is there a way to track this?

[activityVC setCompletionWithItemsHandler:
 ^(NSString *activityType, BOOL completed, NSArray *returnedItems, NSError *activityError) {

     if (completed)
     {
         [GoogleAnalytics trackShareEvents:activityType];
     }else
     {
         [GoogleAnalytics trackEventWithCategory:@"Share" action:@"Failed/Canceled" eventLabel:activityType];
     }
 }];