Date components that uniquely identify the day represented by the summary object.
- iOS 9.3+
- Mac Catalyst 13.0+
- watchOS 2.2+
The calendar used to calculate the date components.
Date components that uniquely specify a day. For example, for the Gregorian calendar, the date components consist of only the era, year, month, and day.
Each activity summary covers a single day. The day always begins and ends at midnight; however, the day may be longer or shorter than 24 hours (for example, if the user traveled across time zones).