Unresolved reference: viewModelScope - Kotlin Android

Question

I try to add viewModelScope to a basic viewModel but android studio doesn't recognize it.

I tried to change my gradle build file with some solution I found but nothing works.

Here an extract of my build.gradle app

implementation "androidx.lifecycle:lifecycle-viewmodel-ktx:2.2.0-alpha01"
implementation "androidx.lifecycle:lifecycle-livedata-ktx:2.2.0-alpha01"
implementation "androidx.lifecycle:lifecycle-viewmodel-savedstate:1.0.0-alpha01"
kapt "androidx.lifecycle:lifecycle-compiler:2.2.0-alpha01"

When I type viewModelScope in my viewModel it say Unresolved reference: viewModelScope.

I have it working using `androidx.lifecycle:lifecycle-viewmodel-ktx:2.1.0-beta01`. — CommonsWare, May 25 '19 at 14:38

score 99 · Accepted Answer · edited Sep 29 '20 at 15:00

99

for now its in alpha, so please update your gradle to use the following dependencies:

implementation "androidx.lifecycle:lifecycle-viewmodel-ktx:2.2.0"

edited Sep 29 '20 at 15:00

AliSh

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answered Jun 02 '19 at 07:38

j2emanue

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score 21 · Answer 2 · answered Sep 02 '20 at 16:03

21

In my case i forgot to extends ViewModel in that class, the class you use for viewModelScope must be like yourModelClass : ViewModel() in kotlin and for java yourModelClass extends ViewModel

Hope its help

answered Sep 02 '20 at 16:03

lukman nudin

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score 8 · Answer 3 · answered Jan 13 '20 at 14:17

8

I've had the same issue and I've just imported: "androidx.navigation:navigation-fragment-ktx:2.2.0-rc03" "androidx.lifecycle:lifecycle-livedata-ktx:2.2.0-rc03" Even though I thought fragment-ktx was not really related. Took me a while to figure that out. Hope it helps!

answered Jan 13 '20 at 14:17

Fernando Prieto Moyano

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Can someone explains why "androidx.navigation:navigation-fragment-ktx" is related to viewModelScope?? – Erfan Eghterafi Dec 09 '20 at 15:55

score 4 · Answer 4 · answered Dec 02 '20 at 12:32

Also check that you are in the correct file. I had the same problem for a moment and I came to this page, but later on, I realized I accidentally tried to run viewModelScope.launch on my Fragment.

viewModelScope.launch is only available in your ViewModels and lifecycleScope.launch in your lifecycle aware components.

score 3 · Answer 5 · answered Dec 13 '19 at 07:41

For latest version of the artifact refer Maven Repository Android Lifecycle ViewModel Kotlin Extensions

In app level build.gradle file add the following :-

def lifecycle_version = "2.2.0-rc03"
implementation "androidx.lifecycle:lifecycle-viewmodel-ktx:$lifecycle_version"
implementation "androidx.lifecycle:lifecycle-livedata-ktx:$lifecycle_version"
kapt "androidx.lifecycle:lifecycle-compiler:$lifecycle_version"

Don't forget to add apply plugin: 'kotlin-kapt' at the top of app/build.gradle file

score 3 · Answer 6 · answered Apr 13 '22 at 04:56

3

Maybe you are not extending the activityViewModel with ViewModel class

class SampleActivityViewModel: ViewModel() {

 fun getData(){
     viewModelScope.launch{
       // Make an API call
     }
   }
}

answered Apr 13 '22 at 04:56

Sanket Bhangale

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score 2 · Answer 7 · answered Sep 27 '20 at 19:55

viewModelScope was introduced with release 2.1.0, see here.

Check whether lifecycle-viewmodel-ktx-2.2.0-alpha01.aar is installed. For me there is no error message with the settings you wrote. However, there is an error message when using an earlier version:

implementation "androidx.lifecycle:lifecycle-viewmodel-ktx:2.0.0"

But this works:

implementation "androidx.lifecycle:lifecycle-viewmodel-ktx:2.1.0"

score 2 · Answer 8 · answered Sep 30 '22 at 15:48

2

Remove below config from build.gradle(:app)

configurations {
    all {
        exclude group: 'androidx.lifecycle', module: 'lifecycle-viewmodel-ktx'
    }
}

answered Sep 30 '22 at 15:48

Jayesh Suthar

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score 1 · Answer 9 · answered Oct 24 '22 at 18:19

In Build.gradle (App Level)

Change your code from:

def lifecycle_version = "2.0.0" or if you are using any lower version than this to:

def lifecycle_version = "2.2.0"

viewModelScope was launched in 2.2.0 version of lifecycle module so you won't find it before that.

score 0 · Answer 10 · answered Oct 28 '19 at 23:20

It looks like you've got two different versions of the androidX lifecycle libraries in use.

Change your app/build.gradle to be:

...
implementation "androidx.lifecycle:lifecycle-viewmodel-ktx:2.2.0-alpha01"
implementation "androidx.lifecycle:lifecycle-livedata-ktx:2.2.0-alpha01"
implementation "androidx.lifecycle:lifecycle-viewmodel-savedstate:2.2.0-alpha01"
kapt "androidx.lifecycle:lifecycle-compiler:2.2.0-alpha01"
...

score 0 · Answer 11 · answered Oct 18 '22 at 06:50

0

ViewModelScope only added in version 2.2.0, not available on higher versions too. I tried with 2.6.0 but got same error.

answered Oct 18 '22 at 06:50

Ashik Lanjewar

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score 0 · Answer 12 · edited Jul 20 '23 at 12:58

0

your ViewModel must extend androidx.lifecycle.ViewModel. if it doesn't, the Android studio doesn't recognize viewModelScope.

class RegisterViewModel() : ViewModel()  {
    fun postRegister(registerBody: RegisterBody) = viewModelScope.lunch{

    }
}

edited Jul 20 '23 at 12:58

helvete

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answered Jul 17 '23 at 13:24

Hossein Zare

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Unresolved reference: viewModelScope - Kotlin Android

12 Answers12