ios - UIActivityViewController completion handler returns success when tweet has failed

Question

I'm using a UIActivityViewController to display a share sheet so users can share my app. I'm currently testing tweets and i'm getting some unexpected results. On tweeting for the first time, all goes well. On the second time, i'm getting a duplicate tweet error message, which is expected. The problem is that the completionWithItemsHandler is returning success: Bool as true!

I want to be able to display my own personalised message to the user rather than the massive one that is returned currently.

Here is my code:

@IBAction func ShareButtonTapped(sender: AnyObject) {
    let textToShare = "I'm using Buzz!  The new way to send emoji's, with sound, it's annoying, funny and amazing"
    var url = NSURL(string: "-Image url masked out-")
    var data = NSData(contentsOfURL: url!)
    let image = UIImage(data: data!)
    if let myWebsite = NSURL(string: "-redirect masked out-")
    {
        let objectsToShare = [textToShare, myWebsite]
        let activityVC = UIActivityViewController(activityItems: objectsToShare, applicationActivities: nil)
        activityVC.completionWithItemsHandler = {
            (activity, success, items, error) in
            println("Activity: (activity) Success: (success) Items: (items) Error: (error)")
        }
        self.presentViewController(activityVC, animated: true, completion: { () -> Void in

        })
    }
}

Here is my log:

2015-01-27 11:10:58.021 Buzz[3239:813859] LaunchServices: invalidationHandler called
2015-01-27 11:10:58.052 Buzz[3239:813860] LaunchServices: invalidationHandler called Activity: com.apple.UIKit.activity.PostToTwitter Success: true Items: nil Error: nil
2015-01-27 11:11:04.134 Buzz[3239:813859] LaunchServices: invalidationHandler called
2015-01-27 11:11:09.182 Buzz[3239:813859] plugin com.apple.share.Twitter.post invalidated

Answer 1

Use completion handler like this For SWIFT 3 AND 4, iOS 10 AND 11 :

activityVC.completionWithItemsHandler = {(activityType: UIActivityType?, completed: Bool, returnedItems: [Any]?, error: Error?) in
    if !completed {
        // User canceled 
        return
    }
    // User completed activity
}

self.present(activityVC, animated: true, completion: nil)