How to inject a ViewModel into a composable function using Hilt (Jetpack Compose)

Question

I'm doing the same as shown in the documentation here. I want to Inject the ViewModel into a Composable function (Screen), but I get this error:

Cannot create an instance of class com.example.blotube.ui.later.LaterViewModel

My ViewModel:

@HiltViewModel
class LaterViewModel @Inject constructor(
    private val database: Database
):ViewModel() {

    val watchLater=database.videos().getAll()

}

My Composable Function (Screen):

@Composable
fun WatchLater(vm: LaterViewModel = viewModel()){


    val videos=vm.watchLater.observeAsState()
    val context= LocalContext.current
    

}

Carmen · Accepted Answer · 2022-07-06 18:12:51Z

66

From version androidx.hilt:hilt-navigation-compose:1.0.0-alpha02 you can inject view model into Composable functions by:

hiltViewModel<ViewModelType>()

Example:

@Composable 
fun LoginScreen(viewModel: LoginViewModel) {}

LoginScreen(
    viewModel = hiltViewModel<LoginViewModel>()
)

Android Developer Documentation compose and hilt

UPDATE:

import androidx.hilt.navigation.compose.hiltViewModel

@Composable 
fun LoginScreen(
    viewModel: LoginViewModel = hiltViewModel()
){
   val videos=vm.watchLater.observeAsState()
   val context= LocalContext.current
}

edited Jul 6, 2022 at 18:12

Carmen

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answered Jun 11, 2021 at 21:05

Sepehr

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8 Comments

bene25 Over a year ago

Simply use inside compose exampleViewModel: ExampleViewModel = viewModel()

deviant Over a year ago

seems hiltViewModel() isn't available anymore

G. Ciardini Over a year ago

Following your setup I got the following error: CreationExtras must have a value by SAVED_STATE_REGISTRY_OWNER_KEY

desgraci Over a year ago

Can you provide an example with @AssistedInject?

Abel Over a year ago

check this @desgraci medium.com/scalereal/…

|

OtienoSamwel · Accepted Answer · 2022-01-27 09:08:07Z

13

I find the simplest way to do it is inside your composable function. Add the dependency implementation 'androidx.hilt:hilt-navigation-compose:1.0.0' then;

@Composable 
fun Foo(){
    val viewModel : Bar = hiltViewModel()
}

then you can use the viewmodel as usual.

edited Jan 27, 2022 at 9:08

answered Jan 27, 2022 at 8:55

OtienoSamwel

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1 Comment

jonathan3087 Over a year ago

I added the dependency to my build.gradle, found that the version is up to 1.2.0 now as of 2/2024. Imported it in my Composable file, but It doesn't find hiltViewModel() Any suggestions?

Jared Burrows · Accepted Answer · 2022-09-08 18:14:57Z

11

You can use ViewModel directly inside Composable function via hiltViewModel()

@Composable
fun WatchLater(vm: LaterViewModel = hiltViewModel()) {

  val videos = vm.watchLater.observeAsState()
  val context = LocalContext.current

}

Please make sure to add following

Adding androidx.hilt:hilt-navigation-compose dependency to your module level Gradle file. Do check for latest version(tested on 1.0.0-alpha03).
@HiltViewModel to your ViewModel.
@AndroidEntryPoint for the owner using the Composable function.

edited Sep 8, 2022 at 18:14

Jared Burrows

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answered Nov 14, 2021 at 13:35

Jatin Sachdeva

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2 Comments

user16422658 Over a year ago

I am getting hiltViewModel() as an unresolved reference

jonathan3087 Over a year ago

@user16422658 me too, were you ever able to resolve?

Francesc · Accepted Answer · 2021-04-20 16:10:37Z

6

This appears to be a bug in Jetpack Compose, will probably need to wait for an update on the Jetpack libraries to address it.

As a possible workaround, you could instantiate the viewmodel in your activity and pass it to your composable function

val viewModel: LaterViewModel = viewModel(
    "later_viewmodel",
    factory = defaultViewModelProviderFactory
)
WatchLater(viewModel)

if you are using the Nav graph component you can also scope your viewmodel to the nav graph using

val viewModel: LaterViewModel = hiltNavGraphViewModel<LaterViewModel>()
WatchLater(viewModel)

answered Apr 20, 2021 at 16:10

Francesc

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1 Comment

Karim Sinouh Over a year ago

Thank you so much, I think scoping the view model to the nav graph is my best solution for now.

Chandra Shekhar · Accepted Answer · 2023-02-14 13:37:26Z

3

base document Inject Hilt In Composable Function

Note: notice to import class

Sample you can used viewModel()

Example:

...
import androidx.lifecycle.viewmodel.compose.viewModel
...
@Composable
fun MyScreen(
    viewModel: MyViewModel = viewModel()
) { /* ... */ }

Full Example:

...
import androidx.lifecycle.viewmodel.compose.viewModel
...
@HiltViewModel
class MyViewModel @Inject constructor(
    private val savedStateHandle: SavedStateHandle,
    private val repository: ExampleRepository
) : ViewModel() { /* ... */ }

@Composable
fun MyScreen(
    viewModel: MyViewModel = viewModel()
) { /* ... */ }

edited Feb 14, 2023 at 13:37

Chandra Shekhar

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answered Jan 2, 2023 at 20:32

Rahman Rezaee

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