This app is an attempt to build a very simple document-based SwiftUI app.
I've updated the SimpleDocAppDocument struct to adopt the changes to the FileDocument protocol introduced in beta 5.
The issue with the user interface and date model not updating after the first edit no longer happens on Big Sur beta 5.
The issue still seems to happen in iOS apps in beta 5, however it is difficult to test since new documents cannot be created due to a known issue mentioned in the release notes.
I have filed Feedback FB8205080 with Apple because this basic setup does not seem to work on iOS of macOS as of Xcode/Big Sur beta 3.
I am posting this project here since it is quite possible I am doing something wrong, since I am not yet well-versed in SwiftUI.
This app follows the steps in the WWDC20 session ‘Build document-based apps in SwiftUI’.
The data model is an Array of items of type SimpleItem. A SimpleItem has a constant UUID id, a constant String name, and a variable Int.
The app is a list-detail showing items in the source list and editing the SimpleItem’s Int property with a Stepper.
You can build and run the macOS app on BigSur beta 3, or build the iOS app and run it on an iPad/iPad sim in landscape to see the issue:
Updating the user interface and updating the data model fail after the first edit.
Feel free to post any hints as to what I might be doing wrong to @jamesdempsey on Twitter. Or submit a pull request with a fix if I'm doing something wrong.
Thanks!