Routing with UITabBarController scenario

[dagio]

UITabBarController allow to have multiple navigation stacks in each tabs. For example :

On the previous image we can see tat we have 4 different stacks at the same time :

• A / Y /
• B / X /
• C /
• D /

The NavigationState design is :

public struct NavigationState {
    public init()
    public var route: Route
    public var routeSpecificState: [ReSwiftRouter.RouteHash : Any]
}

I'm struggling to find a way to use the current implementation while maintaining the native behaviour of the UITabBarController. The idea is to have the following scenario to work properly

Sequence	NavigationState.route	Next user action
1	/	Tab on A in tab bar
2	/ A	Tap on Y in A
3	/ A / Y	Tab on B in tab bar
4	/ B	Tap on A in tab bar
5	/ A / Y

Given the current implementation, NavigationState.route in the 5th sequence would be / A instead of / A / Y because the user action in the 4th sequence is destructive.

It seems that we should support non-linear navigation. Maybe more something like a route tree along with the current route in that tree.

[DivineDominion]

Interesting. Sounds like you could get past this by having a tab navigation history state where for each root node (A or B, not X or Y) the last active route is stored. Extending NavigationState would be nice, but structs don't provide inheritance, so maybe moving this into a PR once the concept works would be best. It's not a tree state, but it's at least aware of the user's past.

[dagio]

Interesting. Sounds like you could get past this by having a tab navigation history state where for each root node (A or B, not X or Y) the last active route is stored.

By "tab navigation history state", you mean a NavigationState for each tab (UIViewController) ?

That would still require some change on the Router to avoid him to ask A to pop Y ?

[jondwillis]

I have an extremely complicated solution for this that is still causing a lot of crashes in an app nearing production due to invalid route states. Basically this is a difficult problem to deal with due to the myriad ways that UIKit navigation can occur that you pretty much have to mirror. Or, I guess you can limit the ways that you interact with UIKit navigation.

My solution consists of a RouterNavigationController and a RouterTabController, a "settled" route state Observable, and some complicated Route logic and traversal that all work together to report user-generated state changes to ReSwift, programmatic state changes that occur without the use of SetRouteAction (e.g. Segues), handling SetRouteActions...

It is truly spaghetti code

@dagio @jondwillis is it possible to make a UITabBarController that supports routing agnostic of the ReSwift-Router? I've started a repo for it, RoutableUIKit, where I thought we might gather UIKit components that supports routing while being agnostic of which routing logic that is being used.

[kdawgwilk]

I also have the same need to support TabBarController tabs with independent navigation stacks

[ciathyza]

We need something very similar, essentially a struct MultiNavigationState that has a different navigation state for every tabbar page that can keep track of everyone of these. Any thoughts on this? How difficult would it be to change ReSwiftRouter to support this?