ViewModel: an ObservableObject that encapsulates the business logic and allows the View to observe changes of the state.
When the View appears on the screen, the onAppear callback calls loadCountries() on the ViewModel, triggering the networking call for loading the data inside WebService. ViewModel receives the data in the callback and pushes the updates through @Published variable countries, observed by the View.
Each view should have its own ViewModel. But there is no need to model the entire hierarchy. Only what the view needs.
- The Model-oriented View Model (MVM), while low in code duplication, is a nightmare to maintain.
- The View-oriented View Model (VVM) produces highly-specialised classes for each view, but contains duplicates.
Having one VM per View is easier to maintain and code for.
NavigationList in the sub-board is a bad component. The only way to make it work is to use List and ForEach together. You could use just List to iterate, but there is no way to use drag-n-drop, as it breaks UI behavior. When used together, you get the onMove() on ForEach that is the only way to use drag-n-drop.
This is not working:
.environment(\.colorScheme, appThemeSetting.appTheme(colorScheme))Sheets, for example, are not getting themed.
Form changes elements behavior and look. Example: the placeholder for a TextField.