swiftswift3xcode8apple-watch-complicationclockkit

watchOS 3 getSupportedTimeTravelDirections

I am trying to update my watchOS 2 app with complications to watchOS 3. Unfortunately I don't understand what I am doing wrong regarding the ComplicationController. I always get the following error (using Xcode 8 b6):

Type 'ComplicationController' does not conform to protocol 'CLKComplicationDataSource' Candidate has non-matching type '(CLKComplication, (CLKComplicationTimeTravelDirections) -> Void) -> ()'

Code:

class ComplicationController: NSObject, CLKComplicationDataSource {

    func getSupportedTimeTravelDirections(for complication: CLKComplication, withHandler handler: (CLKComplicationTimeTravelDirections) -> Void) {
        handler([.forward])
    }
...
}

I also tried:

handler(.forward)

Both approaches give me an error on watchOS 3 but work perfectly fine on watchOS 2 / Swift 2. Does someone have an idea what changed in Swift 3 regarding this function?

Solution

  • From the Xcode 8 beta 6 release notes:

    Closure parameters are non-escaping by default, rather than explicitly being annotated with @noescape. Use @escaping to indicate that a closure parameter may escape.

    If you created a new ComplicationController.swift project in Xcode 8 beta 6, the generated source code would now look like:

    func getSupportedTimeTravelDirections(for complication: CLKComplication, withHandler handler: @escaping (CLKComplicationTimeTravelDirections) -> Void) {
    handler([.forward, .backward])
}

    This change applies to every data source method that has a handler parameter.