UIActivityItemProvider.item should be optional

I known this post is super old, but I just wanted to comment that I've filed a radar suggesting that the

item

property be made nullable: openradar.me/radar?id=4563896690016256

Please file your own bug report if you agree!

Hi,

since UIActivityItemProvider inherits from NSOperation maybe sending a cancel message to self will do the trick. (Just a wild guess).

Dirk

Unfortunately that won't work.

We start loading the data when the `item` getter is called and from there we have to return something - no matter if the op was cancelled or not.

My current workaround is to return an instance of an empty dummy class no one cares about.

I ended up figuring out a pretty good workaround for this. While UIActivityItemProvider includes a bunch of its own functionality, it still very much implements the UIActivityItemSource protocol. I knew that. What I hadn't considered is that this means I can just override

activityViewController:itemForActivityType:

and return

nil

there when it's appropriate.

So the last line of my

item

method now looks like this:

return self.placeholderItem;

You could also return

[NSNull null]

here, or really any object. I chose the placeholderItem because it seems a little safer—at the very least I know it's returning an object of the expected type, in case anything about the implementation ever changes.

Then all I have to do is add my own implementation of

activityViewController:itemForActivityType:

(where we are allowed to return nil):

- (nullable id)activityViewController:(UIActivityViewController *)activityViewController itemForActivityType:(UIActivityType)activityType {
     id item = [super activityViewController:activityViewController itemForActivityType:activityType];
     if ([item isEqual:self.placeholderItem]) return nil;
     return item;
}

Just call super to get the item, return nil if it's something you don't want to include, or return the item if it is. Note that if your

placeholderItem

might ever be equal to something you actually dowant to share, you will need to change this implementation a bit—but the same basic concept should work.