In this chapter, you learned about HealthKit. You learned what it is, how to ask the user for permissions, and how you can read and write data in the HealthKit store. This chapter put a lot of focus on using HealthKit to track a user's activity, but HealthKit is capable of tracking much more data. You can build apps that help users track just about anything related to their health.
When you build an app that accesses a user's health data, make sure that you don't request access to information that you don't need. It's usually better to ask the user for permission to access certain data just before you need it than to ask for all permissions at once. For instance, you might build an app that tracks both sleep and blood sugar, but not necessarily at the same time. You might want to ask permission to access each of these data types separately, so...
