IMHO that’s one of the main benefits of following the Model-View-ViewModel architecture pattern for GUIs. You can have all the models and viewmodels defined in a platform agnostic library, and your views are the only thing to implement in a platform specific way. The core library can be implemented in any language, you just need a way to call methods and setters when the user interacts, and handle update events to update the UI.
This seems like a really good idea! But at second glance, won’t differences between the UI designs on different platforms require subtly different viewmodels for each platform?
Not if you make the exqct same UI on each platform I bet, but if you do that, you might as well use something like Flutter or React Native and only code the whole thing once, no?
Yes, there are differences between platforms, complicating the picture a bit. There is a bit of a trade off/judgement calls when deciding what needs to be in the core library and what to keep on the platform specific code. You can always wrap a shared view model with a more specific one if you have to account for a few differences, or just decide to keep a bit of logic in the view. If you have >80% of your viewmodels that can be shared between platforms, MVVM can be really useful (just my own rule of thumb). If you have more differences between platforms I guess you will want to try something else.
Regarding Flutter, then yes I agree with you, their approach is different, it’s more adapted if you want to design a single UI that will be rendered the same on every platform, without relying on native controls.
