When I setup an HKObserverQuery, the update handler always gets immediately called (something I didn't expect). It also gets called when I add data points through Health.app, as you would expect. I am tending to think I am not doing something right with the completion handler, but the docs are fairly sparse on what is supposed to happen here.
Question: Below is basically what I'm doing. Is this expected behavior, or am I missing something?
func listenForUpdates() {
let bodyMassType = HKQuantityType.quantityTypeForIdentifier(HKQuantityTypeIdentifierBodyMass)
let updateHandler: (HKObserverQuery!, HKObserverQueryCompletionHandler!, NSError!) -> Void = { query, completion, error in
if !error {
println("got an update")
// ... perform a sample query to get the actual data
completion() // is this the right thing to do?
} else {
println("observer query returned error: \(error)")
}
}
let query = HKObserverQuery(sampleType: bodyMassType, predicate: nil, updateHandler: updateHandler)
healthStore?.executeQuery(query)
}
Edit: discovered completion handler should only be called when there wasn't an error, so moved into the !error block. An error is present when the app is not authorized.