Compose viewModel() doesn't allow you to pass in a ViewModelStoreOwner [188693123]

Fixed

Bug

Status Update

No update yet.

Description

ng...@gmail.com

created issue #1

May 19, 2021 08:18PM

Component used: ViewModel Version used: 2.3.1 Devices/Android versions reproduced on: Emulator API 29

I just want to share a ViewModel object across navigation changes (using Jetpack Compose). I mean, ScreenA is instantiating MyViewModel using viewModel() function. When I navigate (using Jetpack Navigation for Compose) to ScreenB and call viewModel() from there, it returns a different instance.

My current solution is a little ugly...

NavHost(navController = navController, startDestination = ROUTE_WELCOME) {
    ...
    composable(ROUTE_SCREEN_A) {
        ScreenA(
            onNext = { navController.navigate(ROUTE_SCREEN_B) }
        ) // inside of this function, I'm calling viewModel()
    }
    composable(ROUTE_SCREEN_B) {
        // TODO improve this
        val vm = ViewModelProvider(navController.previousBackStackEntry!!)
                .get(MyViewModel::class.java)
        ScreenB(vm)
    }
}

There's no viewModel() method that takes a ViewModelStoreOwner. It just always uses the LocalViewModelStoreOwner.current.

Comments

il...@google.com <il...@google.com> May 19, 2021 08:20PM

Reassigned to il...@google.com.

il...@google.com <il...@google.com> May 20, 2021 07:31PM

Accepted by il...@google.com.

ap...@google.com <ap...@google.com> #2Jun 9, 2021 06:11PM

Project: platform/frameworks/support
Branch: androidx-main

commit 0c44ec9ae8a43abafd966cd130196e9334fad359
Author: Ian Lake <ilake@google.com>
Date: Wed May 19 16:05:43 2021

Provide a ViewModelStoreOwner parameter for viewModel()

The current viewModel() always uses the
LocalViewModelStoreOwner.current value as the
ViewModelStoreOwner. This means when using
an alternate ViewModelStoreOwner (such as one
from a parent navigation graph, previousBackStackEntry,
or from the containing activity), developers have
needed to use ViewModelProvider directly.

By providing a parameter of viewModel() that takes
an explicit ViewModelStoreOwner, developers can
use the same syntax.

In cases where the Factory depends on the owner,
developers would get the owner first, build the
factory, then pass both to viewModel:

val owner = OwnerProvider.get()
val factory = Factory(owner)
val viewModel: MyViewModel = viewModel(owner, factory)

Relnote: "Added a new `viewModel()` overload that takes an
explicit `ViewModelStoreOwner`, making it easier to work
with owners other than the `LocalViewModelStoreOwner`."
Test: updated ViewModelTest tests pass
BUG: 188693123

Change-Id: I2628d27791bfeb8a0d2f45b0fa8e9e72cb00c34b

M hilt/hilt-navigation-compose/api/current.txt
M hilt/hilt-navigation-compose/api/public_plus_experimental_current.txt
M hilt/hilt-navigation-compose/api/restricted_current.txt
M hilt/hilt-navigation-compose/src/main/java/androidx/hilt/navigation/compose/HiltViewModel.kt
M lifecycle/lifecycle-viewmodel-compose/api/current.txt
M lifecycle/lifecycle-viewmodel-compose/api/public_plus_experimental_current.txt
M lifecycle/lifecycle-viewmodel-compose/api/restricted_current.txt
M lifecycle/lifecycle-viewmodel-compose/src/androidTest/java/androidx/lifecycle/viewmodel/compose/ViewModelTest.kt
M lifecycle/lifecycle-viewmodel-compose/src/main/java/androidx/lifecycle/viewmodel/compose/ViewModel.kt

https://android-review.googlesource.com/1712556

il...@google.com <il...@google.com> #3Jun 9, 2021 06:26PM

Marked as fixed.

viewModel() has been updated to take an optional ViewModelStoreOwner parameter (in addition to the optional key and factory it already had). This parameter defaults to LocalViewModelStoreOwner.current, maintaining the same behavior when using viewModel():

composable(ROUTE_SCREEN_B) {
    // tada:
    val vm: MyViewModel = viewModel(navController.previousBackStackEntry!!)
    ScreenB(vm)
}

Note that hiltViewModel() has been updated as well to rely on this new API and now mirrors the API surface of viewModel() in that it takes an optional ViewModelStoreOwner, such as any NavBackStackEntry you'd get from Navigation.

This will be available in lifecycle-viewmodel-compose:1.0.0-alpha07 and hilt-navigation-compose:1.0.0-alpha03.

me...@gmail.com <me...@gmail.com> #4Nov 19, 2021 08:35AM

Necesito que mi celular pase a versión 10, aun no lo actualizan. Gracias

Issue 188693123