Exclude own samples from healthkit queries

Question

I'm writing an app that amongst other things, reads weight samples from HealthKit.
I'm also writing samples.
I'm trying to read the latest sample that isn't mine:

NSPredicate* non_fdct = [NSCompoundPredicate notPredicateWithSubpredicate:[HKQuery predicateForObjectsFromSource:[HKSource defaultSource]]];
NSSortDescriptor *last = [[NSSortDescriptor alloc] initWithKey:HKSampleSortIdentifierEndDate ascending:NO];
HKSampleQuery* query = [[HKSampleQuery alloc] initWithSampleType:[HKQuantityType quantityTypeForIdentifier:HKQuantityTypeIdentifierBodyMass] predicate:non_fdct limit:1 sortDescriptors:@[last] resultsHandler:^(HKSampleQuery *query, NSArray *results, NSError *error) {  ... };

But I'm getting my own samples if they are the latest samples.
Any idea?

Answer 1

The way you have constructed the non_fdct predicate is not quite correct. Try this instead:

NSPredicate *non_fdct = [NSPredicate predicateFromString:@"%K != %@", HKPredicateKeyPathSource, [HKSource defaultSource]];