healthkitlisted

# HealthKit Read and write health and fitness data from the Apple Health store. Covers authorization, queries, writing samples, background delivery, and workout sessions. Targets Swift 6.3 / iOS 26+. ## Contents - [Setup and Availability](#setup-and-availability) - [Authorization](#authorization) - [Reading Data: Sample Queries](#reading-data-sample-queries) - [Reading Data: Statistics Queries](#reading-data-statistics-queries) - [Reading Data: Statistics Collection Queries](#reading-data-statistics-collection-queries) - [Writing Data](#writing-data) - [Background Delivery](#background-delivery) - [Workout Sessions](#workout-sessions) - [Common Data Types](#common-data-types) - [HKUnit Reference](#hkunit-reference) - [Common Mistakes](#common-mistakes) - [Review Checklist](#review-checklist) - [References](#references) ## Setup and Availability ### Project Configuration 1. Enable the HealthKit capability in Xcode (adds the entitlement) 2. Add `NSHealthShareUsageDescription` (read) and `NSHealthUpdateUsageDescription` (write) to Info.plist 3. For background delivery, enable the "Background Delivery" sub-capability ### Availability Check Always check availability before accessing HealthKit. iPad and some devices do not support it. ```swift import HealthKit let healthStore = HKHealthStore() guard HKHealthStore.isHealthDataAvailable() else { // HealthKit not available on this device (e.g., iPad) return } ``` Create a single `HKHealthStore` instance and reuse i