Filtering HKSample data which are not from my application

Question

In my current project, I need to sync with HealthKit samples with my application. I am fetching sample data from HealthKit and writing some app generated samples back to HealthKit. For fetching I'm using the following function:-

private func readHealthKitSample(sampleType:HKSampleType, limit: Int, startDate: NSDate, endDate: NSDate, completion: (([HKSample]?, NSError!) -> Void)!){

    let mostRecentPredicate = HKQuery.predicateForSamplesWithStartDate(startDate, endDate:endDate, options: .None)

    // 2. Build the sort descriptor to return the samples in descending order
    let sortDescriptor = NSSortDescriptor(key:HKSampleSortIdentifierStartDate, ascending: false)

    // 3. we want to limit the number of samples returned by the query to just 1 (the most recent)
    let limit = limit

    // 4. Build samples query
    let sampleQuery = HKSampleQuery(sampleType: sampleType, predicate: mostRecentPredicate, limit: limit, sortDescriptors: [sortDescriptor])
        { (sampleQuery, results, error ) -> Void in

            if let error = error {
                self.Logger.error("HealthKit Sample Data Fetch Error: \(error.localizedDescription)")
                completion(nil , error)
                return;
            } else {
               // self.Logger.debug("HealthKit Sample Data Fetch SUCCESS: \(results)")
            }

            // Execute the completion closure
            if completion != nil {
                completion(results,nil)
            }
    }
    // 5. Execute the Query
    self.healthKitStore.executeQuery(sampleQuery)
}

My app requires not to consider the samples written by itself to HealthKit Store. So, is there a way to filter sample data in a such way that I can avoid receiving them written by my application and consider only those samples written by other apps?

Answer 1

You can use HKSource to filter out your own app and NSCompoundPredicate to combine this with your existing predicate filter:

let mostRecentPredicate = HKQuery.predicateForSamplesWithStartDate(startDate, endDate:endDate, options: .None)
let myAppPredicate = HKQuery.predicateForObjectsFromSource(HKSource.defaultSource()) // This would retrieve only my app's data
let notMyAppPredicate = NSCompoundPredicate(notPredicateWithSubpredicate: myAppPredicate) // This will retrieve everything but my app's data
let queryPredicate = NSCompoundPredicate(andPredicateWithSubpredicates: [mostRecentPredicate, notMyAppPredicate])

let sampleQuery = HKSampleQuery(sampleType: sampleType, predicate: queryPredicate, limit: limit, sortDescriptors: [sortDescriptor]) {
    // Process results here...
}

Swift 5+:

let mostRecentPredicate = HKQuery.predicateForSamples(withStart: startDate, end:endDate, options: [])
let myAppPredicate = HKQuery.predicateForObjects(from: HKSource.default()) // This would retrieve only my app's data
let notMyAppPredicate = NSCompoundPredicate(notPredicateWithSubpredicate: myAppPredicate) // This will retrieve everything but my app's data
let queryPredicate = NSCompoundPredicate(andPredicateWithSubpredicates: [mostRecentPredicate, notMyAppPredicate])

let sampleQuery = HKSampleQuery(sampleType: sampleType, predicate: queryPredicate, limit: limit, sortDescriptors: [sortDescriptor]) {
   // Process results here...
}