Class

HKSample

A HealthKit sample represents a piece of data associated with a start and end time.

Declaration

@interface HKSample : HKObject

Overview

The HKSample class is an abstract class. You should never instantiate a HKSample object directly. Instead, you always work with one of its concrete subclasses: HKCategorySample, HKQuantitySample, HKCorrelation, or HKWorkout classes.

HealthKit samples are all immutable: You set the sample’s properties when you create it, and they cannot change.

If the sample represents data over a duration, the start time must be earlier than the end time. If the sample represents data at a particular instant, the start and end times can be the same.

Topics

Accessing the Sample’s Data

startDate

The sample’s start date.

endDate

The sample’s end date.

sampleType

The sample type.

Sort Identifiers

HKSampleSortIdentifierStartDate

A constant for sorting samples based on their start date.

HKSampleSortIdentifierEndDate

A constant for sorting samples based on their end date.

Predicate Key Paths

HKPredicateKeyPathStartDate

The key path for the sample’s start date.

HKPredicateKeyPathEndDate

The key path for the sample’s end date.

Relationships

Inherits From

See Also

Abstract Superclasses

HKQuantitySample

A sample that represents a quantity, including the value and the units.

HKObject

A piece of data that can be stored inside the HealthKit store.