Is it possible to navigate between activities and have the b

Question

Is it possible to navigate between activities and have the bottom bar work seems like the answer is no for now

Ian Lake · Answer

You mean have each bottom nav item open a brand new activity That hasn t been a recommended pattern well ever lol

codeslubber · Answer

So one activity is a user profile and the other is a FAQ and those should be fragments that share a Viewmodel that sounds great

Ian Lake · Answer

Or since you re in the < CJLTWPH7S|compose> channel composables but yes

codeslubber · Answer

Yeah that s sad I was joking about it sounding great I was so thrilled when Viewmodels arrived and the Blueprint stuff but I guess the right way to do this is just put the various unrelated things in the Drawer Thanks < Ian Lake>

codeslubber · Answer

So I reread the docs but kept searching and found this SO question that < Ian Lake> answered which gave me a surprise Viewmodels can be scoped to Fragments the documentation does not show how that s done though in the docs they show a Master sic Detail that shares data between the fragments which is cool

Ian Lake · Answer

You can scope ViewModels to activities fragments navigation graphs or composables in a Navigation Compose graph yup

Ian Lake · Answer

The fragment docs talk about using ViewModels in Fragments FWIW <https developer android com guide fragments saving state nonconfig>

Ian Lake · Answer

Same as how the Navigation docs talk about using navigation graph scoped ViewModels <https developer android com guide navigation navigation programmatic share ui related data between destinations with viewmodel>

Ian Lake · Answer

In a Compose world you use `= viewModel ` <https developer android com jetpack compose interop viewmodel>

Ian Lake · Answer

Which if you re using Navigation Compose <https developer android com jetpack compose navigation> will automatically scope your `ViewModel` to the current destination if used within the `NavHost`

codeslubber · Answer

so then to summarize my mistake was to start with the Viewmodels page in the docs wink this is great thanks

Ian Lake · Answer

Yeah ViewModels are one of the lowest level building blocks lower level than fragments or Navigation You d have to go to the docs on the higher level components to find out how they expose those lower level building blocks

codeslubber · Answer

Well I would suggest that the Viewmodels page mention that they can be scoped to all those things When they were first introduced they were scoped only to Activities

codeslubber · Answer

But thanks on the whole samples and docs in android are amazing

Ian Lake · Answer

You mean when they were first introduced in the docs Because ViewModels themselves had support for fragments on day 1 way back before AndroidX was even a thing

Ian Lake · Answer

Do you mind filing a documentation bug for the ViewModel page I think there could at least be a few more learn more links at the bottom pointing to the other pages <https issuetracker google com issues new component=192697>

codeslubber · Answer

Yeah I am happy to do that

codeslubber · Answer

On the first issue I am not saying they did not have support for fragments I am saying they were scoped to the activity so the share one viewmodel between one or more fragments sure that worked a different viewmodel for different fragments I don t think so

Ian Lake · Answer

The `ViewModelProviders of Fragment ` method which allowed fragment scoped ViewModels is in the very first `android arch lifecycle lifecycle extensions 1 0 0 alpha01` release slightly smiling face

codeslubber · Answer

I was wrong perfect slightly smiling face

codeslubber · Answer

That s interesting but since that was before the Single Activity reborn movement not sure how germane