In your Watch's session didReceiveUserInfo function you need to update the ViewModel variable (i.e. data that get displayed) using DispatchQueue.main.async { update the var } as you probably did in the phone app if using my sample code. This is because communication sessions are run on a background queue, whereas views (and their associated data) can only be updated on the main queue. Good luck and regards, Michaela

OK, will do - sometime later today (I'm in Australia so just getting started on the day)

Well done! It's good to see another retireee doing app development. I'd already assumed you are very tech savvy, although, yes, Swift and particularly SwiftUI can be hard to get one's head around (was for me, anyway) after years of procedural programming. Sharing of the phone and watch ViewModal code is the best way to go (though potentially more complex), especially if both devices will have the same functionality. Normally I use a separate Framework (library) for all of my Data Model (ViewModel) code, with OS specific code as needs be. This is because most of my apps now are Multiplatform (Mac, iPad, iPhone, Watch and sometimes TV), with data sharing via the Cloud: my watch apps are now standalone, i.e. not tethered to the phone. However, your need appears to be for reliable realtime communication, which probably wouldn't suit a Cloud approach

Ooo, that's good! Also useful knowledge for me, in case I need realtime communication in the future. I've done a lot of work with route tracking (e.g. running (as in exercise) app, so would be happy to help out if needs be.

I was in a hurry to get this sample done before visitors arrived, so it's not as robust as it could be. It would be better to initiate the dataTable in DataModel as @Published var dataTable = DataFrame(). With this initialisation, the reference to model.dataTable! in ContentView doesn't need to be (shouldn't be) force unwrapped i.e. just use model.dataFrame. Also, with a large input csv file it would be better to load as a background task (via DispatchQueue) and rely on the @Published var dataTable to populate the SwiftUI List.

Nice solution to making the annotations!! The Map facility within SwiftUI is very limited, basically restricted to showing annotations at known coordinates, e.g. giving it coords you already have somewhere in your data (or per your idea). There's no way of plotting a track either ( a poly line). To put an annotation on the map with a tap or long-press requires 1) a gesturerecognizer in your SwiftUI View (easy) and 2) a method to convert the press's view x,y location to map coordinates. Unfortunately the latter is only available in the MapKit framework (i.e.not SwiftUI), which then requires a coordinator from SwiftUI to MapKit and some fairly (unfairly??) complex code to manage everything. I've done MapKit coordinators, but there's a lot of code and might be too much to put in a post.

There's been a lot of pressure from developers for SwiftUI Map to have the same capabilities as MapKit, so I expect (hope?) that future releases will make life easier. That said, I'm having problems with a MacOS mapping app, SwiftUI and MapKit coordinator, related to a bug somewhere in Apple code. One of my tasks in the next day or two is to collect all the evidence and submit a bug report.

I've gone back to using UIViewRepresentable for all my mapping needs, except that NSGesturerecognizer seems not to work in certain cases with MacOS and Mac Catalyst apps crash if the app uses polylines.

Thank you for your kind words Harry: much appreciated. I'll answer your questions in another Answer, rather than a comment, because the formatting is easier and better.

Oops, I forgot to mark the realDate var as public. It might work without being public, but I doubt it. Regards, Michaela

Hi Drew, my suggested solution does NOT work. I've used computed properties several times in my apps, but not for sorting, and I just assumed (incorrectly) that the solution would work - but it doesn't: Coredata does not allow sorting by computed property. There's no compiler error, just a crash. Normally I check my answers on the forum before posting, but on this occasion I made a faulty assumption. So, I apologise for wasting your time. Nor can you just change the attribute type to Date from String - this would require a Migration. Best wishes and regards, Michaela

Hi Drew, my suggested solution does NOT work. I've used computed properties several times in my apps, but not for sorting, and I just assumed (incorrectly) that the solution would work - but it doesn't: Coredata does not allow sorting by computed property. There's no compiler error, just a crash. Normally I check my answers on the forum before posting, but on this occasion I made a faulty assumption. So, I apologise for wasting your time. Nor can you just change the attribute type to Date from String - this would require a Migration. Best wishes and regards, Michaela

Yes, that would do the job.

I'm happy to help out when able and available. I'll respond to these questions in another Answer, because the formatting in an Answer is easier to read than in a Comment. Cheers, Michaela.

Thank you for your answer. I'm already using the Web Server built into MacOS for publicly facing web-sites, through the DMZ of my secure gateway to a different Mac. As I said, I don't need a full-blown web server and the Listener App's actions need to use Swift APIs, which are difficult to get to via Apache. I know the local IP addresses of the switch and listener. I've developed other Mac apps that constantly (well, every few seconds - but still always running) monitor blue-tooth devices and this is similar, except that the external device (switch) triggers the app's processing via an HTTP Post rather than Bluetooth connectivity with device update notifications. There will be a simple GUI (SwiftUI), for showing switch events, and events will be stored in CoreData and/or CloudKit (of which I've done many apps). The app will also send out alerts, the mode depending on the switch state reported. So, after further thought and reading, plus your answer, I'm inclined to build my own solution using Network Framework and URLSession - once I've gotten my ageing brain around the complexities. Hopefully I'll find some examples or tutorials to get an overview and options. Regards, Michaela