Different data for sharing providers in UIActivityViewController - objective-c

Question

I'm trying to use an UIActivityViewController with one long NSString as the data. If I put a string > 140 characters, the tweet sheet in it does not display the string. And if I truncate the string before giving it to the controller, all of the UIActivities have the truncated string. I don't want Facebook or Message to be truncated.
Is there a way to give different strings to different UIActivities?
Thank you!
(e.g. Marco Arment's The Magazine app does this by having a truncated string followed by #TheMagazineApp in UIActivityPostToTwitter, and other stuff in other UIActivities.)

Answer 1

I think this is what you're looking for: Custom UIActivityViewController icons and text.
You should be able to provide different data for each activity type.

Answer 2

Hope this helps somebody. It's pretty straightforward if you subclass UIActivityItemProvider:
#interface MyActivityItemProvider : UIActivityItemProvider
#end
#implementation MyActivityItemProvider
- (id)item
{
// Return nil, if you don't want this provider to apply
// to a particular activity type (say, if you provide
// print data as a separate item for UIActivityViewController).
if ([self.activityType isEqualToString:UIActivityTypePrint])
return nil;
// The data you passed while initialising your provider
// is in placeholderItem now.
if ([self.activityType isEqualToString:UIActivityTypeMail] ||
[self.activityType isEqualToString:UIActivityTypeCopyToPasteboard])
{
return self.placeholderItem;
}
// Return something else for other activities. Obviously,
// you can as well reuse the data in placeholderItem here.
return #"Something else";
}
#end
Then pass its instance with an array of activity items to UIActivityViewController:
MyActivityItemProvider *activityItem =
[[MyActivityItemProvider alloc] initWithPlaceholderItem:#"Your data"];
NSArray *sharingItems = [NSArray arrayWithObjects:
activityItem, _myUITextView.viewPrintFormatter, nil];
UIActivityViewController *activityController =
[[UIActivityViewController alloc]
initWithActivityItems:sharingItems applicationActivities:nil];

Answer 3

This can be easily done by using the optional activityType property from the UIActivityItemProvider object. That property returns a UIActivityType, so you can do something like:
class PhotoActivityItemProvider: UIActivityItemProvider {
...
override var item: Any {
guard let activityType = self.activityType else {
return photoURL.absoluteString
}
if activityType == .mail || activityType == .message {
return "The photo link is \(photoURL.absoluteString)."
}
...
}
More information in my blog post: https://www.whitesmith.co/blog/control-what-youre-sharing/

Answer 4

You can create a class that conforms to UIActivityItemSource and then pass its instance with an array of activity items to UIActivityViewController:, as #Mu-Sonic suggested.
If you want to know in which platform is the user sharing and return any specific data dependent on the tapped platform, override public func activityViewController(_ activityViewController: UIActivityViewController, itemForActivityType activityType: UIActivity.ActivityType?) -> Any?