iOS Action Extension Sample Code Not Working

Question

The iOS Action Extension sample code does not seem to work.

1. In xCode, I create a new Swift project and choose Single View Application.

2. Then I se

Answer 1

There's a bug in the Swift version of Xcode's project template for this kind of extension, apparently because of an error when someone was converting from Objective-C to Swift.

To make a long story short: the line that reads "found = true" is in the wrong place. This causes the method doneWithResults to be called twice when it should only be called once. On the first call it sets self.extensionContext = nil. On the second call it tries to use self.extensionContext and throws an exception due to unwrapping a nil optional. But the exception message gets swallowed by the extension system, so there are no clues.

If you change this code in the project template:

itemProvider.loadItemForTypeIdentifier(String(kUTTypePropertyList), options: nil, completionHandler: { (item, error) in
    let dictionary = item as! [String: AnyObject]
    NSOperationQueue.mainQueue().addOperationWithBlock {
        self.itemLoadCompletedWithPreprocessingResults(dictionary[NSExtensionJavaScriptPreprocessingResultsKey] as! [NSObject: AnyObject])
    }
    found = true
})

to look like this:

itemProvider.loadItemForTypeIdentifier(String(kUTTypePropertyList), options: nil, completionHandler: { (item, error) in
    let dictionary = item as! [String: AnyObject]
    NSOperationQueue.mainQueue().addOperationWithBlock {
        self.itemLoadCompletedWithPreprocessingResults(dictionary[NSExtensionJavaScriptPreprocessingResultsKey] as! [NSObject: AnyObject])
    }
})
found = true

...then it works as expected.

I filed the bug rdar://22482042 about this and I encourage you to file one as well.