Routing API revamp RFC

[reactiveui]

Routing API revamp RFC

[kentcb]

👍 A lot of this is in line with my thoughts on re-vamping routing, perhaps for V8. However, I'd prefer stack semantics for NavigationStack members, such as Push and Pop.

But that's pretty much irrelevant minutia right now. I think the important thing is to take routing in a direction that gives us:

• far greater consistency across platforms (by sharing far more code and pushing more responsibility into that shared code)
• far greater flexibility (not dictating so much about how routing occurs at the UI level)
• a story for platforms that aren't VM-first friendly (e.g. Android)

These are difficult problems to solve, and I think we should look for inspiration elsewhere (Prism, MVVMCross etc).

[qrzychu]

When revamping navigation, I would also like something like Router.PushDialog.

This is a common scenario (I think), when I want edit an item in another ViewModel and then fall back to previous VM with new value.

Rigth now I use some hacks like this:

 EditItem = ReactiveCommand.CreateFromObservable<Item, Item>(item =>
            {


                var editVM = new EditItemViewModel(HostScreen, resolver, item);
                HostScreen.Router.Navigate.Execute(editVM).Subscribe();

                
               
                return HostScreen.WhenAnyValue(x => x.CurrentViewModel)
                        .Where(x => x == this)
                        .Take(1)
                        .TakeUntil(HostScreen.Router.NavigationStack.ShouldReset)
                        .Select(x => item);

                // or use EditDone command of EditVM

                return editVM.EditDone.Select(x => item)
                       .Take(1)
                       .TakeUntil(HostScreen.Router.NavigationStack.ShouldReset); 
                 // and navigate back in EditItem.Subscribe
});

I think that with NavigationStack it would be great to write something like this:

return HostScreen.Router.PushDialog.Execute(editVM).Select(x => item);

PushDialog would return editVM when Router.Pop would bring us back to CurrentViewModel and handle all edge cases of navigating to terminate returned observable.

It's quite easy to make an extension method for that, but if you want to revamp the whole thing either way, it could be just built-in functionality.

If there is already a easy way to make it error free, please tell me :)

[glennawatson]

Assigning to @RLittlesII I know he's been wanting to get his feet dirty on this type of thing.