Developing for Apple Watch

Sharing Data Between Apps

All iOS apps are sandboxed, and WatchKit extensions are no different. The unparalleled security this offers means that we need to do a little bit of extra work to allow the WatchKit extension and iPhone app to share data; by default, their sandboxes cannot communicate. To solve this, we’ll create a new App Group, essentially a shared container for file storage for our app. Just like we added the HealthKit capability, head to the TapALap target settings and enable App Groups under Capabilities. Click the + button in the App Groups section to add a new one. We’ll provide a name to Xcode’s Add A New Container dialog box. Much like the bundle ID, this uses reverse DNS-style names as convention, but with group prepended ...