Swift Firebase Append Image for UIActivityViewController - ios

Question

I need help appending a image I downloaded from firebase so I can use it to be share over the UIActivityViewController. I get the right image but unsure how to set up the data pass to let it be shared. The current set up throws a "Thread 1 error" on "objectsToShare = [self.image!]".
let shareAction = UIAlertAction(title: "Share", style: UIAlertActionStyle.default, handler: {(alert: UIAlertAction!) in
var objectsToShare: [AnyObject]?
let titlePost = self.feeds[sender.tag].downloadURL
if let postURL = URL(string: titlePost) {
let postRequest = URLRequest(url: postURL)
self.image?.setImageWith(postURL, placeholderImage: nil, options: SDWebImageOptions.progressiveDownload, completed: { (imageRequest, imageResponse, error) -> Void in
// failure downloading image
print("Error downloading Firebase post image")
print(error)
})
}
objectsToShare = [self.image!]
let activityViewController = UIActivityViewController(activityItems: objectsToShare!, applicationActivities: nil)
// present the view controller
self.present(activityViewController, animated: true, completion: nil)
})

Answer 1

In place of the below:
objectsToShare = [self.image!]
You have to use like this :
if let image = self.image {
objectsToShare.append(image)
}

Answer 2

You should check what a completion handler is first.
You should check for error in the completion, and if there's not, do what you have to do with your image. As the request is asynchronous the image isn't there yet on the line just after.
Do something like that :
self.image?.setImageWith(postURL, placeholderImage: nil, options: SDWebImageOptions.progressiveDownload, completed: { (imageRequest, imageResponse, error) -> Void in
// This closure is called when the request is done
if error == nil {
objectsToShare = [self.image!]
let activityViewController = UIActivityViewController(activityItems: objectsToShare!, applicationActivities: nil)
// present the view controller
self.present(activityViewController, animated: true, completion: nil)
} else {
// failure downloading image
print("Error downloading Firebase post image")
print(error)
}
})