How to make nested graph like android jetpack compose navigation?

[KangTaeJong98]

This is what I want.
https://developer.android.com/guide/navigation/design/nested-graphs

I have to separate feature module and encapsulation navigation. Just open navGraph and protect navigation.

[arkivanov]

You can add a component to Child Stack, and that component can also use Child Stack and so becomes nested. This is equivalent to nested graphs.

Also see the example. DefaultCountersComponent defines its own stack. It is used in DefaultRootComponent in outer stack. We can say that DefaultCountersComponent's graph is nested inside DefaultRootComponent.

[KangTaeJong98]

Thank you for your reply.

I think this case is little bit different. When user in startDestination on nested navigation graph press the back button, go previous navigation. But I think DefaultCountersComponent example is not.

[arkivanov]

In Decompose, the navigation is usually performed in the parent component holding Child Stack. You can pass a callback to the child component (e.g. onFinished: () -> Unit), and in the parent component you can manipulate Child Stack as needed. The parent component can bubble the event up in case the event should be handled on the upper level. So the parent component can also accept a callback, allowing the grandparent to handle the event instead. This is how nested navigation is usually performed. You can have as many nested Child Stacks as you want.

Does this answer your question?

[KangTaeJong98]

I understand what you said. But in android jetpack navigation, nested graph doesn't know parent graph and doesn't have callback like onFinished: () -> Unit just use NavController.naviagteUp() to go to previous route and go to parent graph. And use same NavController. Is there anything like this? 🤔

[arkivanov]

But in android jetpack navigation, nested graph doesn't know parent graph

This contradicts with NavController.naviagteUp(), because NavController instance belongs to the parent.

In Decompose, child components are only aware of its immediate children. The child component accepts a callback, and the parent component (that is aware of the child) makes decisions how to navigate.

[KangTaeJong98]

I'm late. Thank you for your answer :)