Koin 2.2.1 : I cannot use "by viewModel" in Activity

Question

Cannot use "by viewModel" from Activity

I want to inject a ViewModel for an Activity, so I tried this. But it was failed, Android Studio cannot find reference of it.

private val mainViewModel: MainViewModel by viewModel()

My activity extends AppCompatActivity, and gradle dependencies includes these libraries:

implementation 'androidx.core:core-ktx:1.3.2'
def koin_version = '2.2.1'
implementation "org.koin:koin-android:$koin_version"
implementation "org.koin:koin-androidx-scope:$koin_version"
implementation "org.koin:koin-androidx-viewmodel:$koin_version"
implementation "org.koin:koin-androidx-fragment:$koin_version"
implementation "androidx.lifecycle:lifecycle-viewmodel-savedstate:$koin_version"

What I tried:

The code below is working, but I want to use new default "SavedStateHandle" feature of Koin 2.2.0.

private val mainViewModel: MainViewModel by inject()

I found this code was already included, Android Studio cannot find it.

ActivityExt.kt:

inline fun <reified T : ViewModel> ComponentActivity.viewModel(
        qualifier: Qualifier? = null,
        noinline state: BundleDefinition? = null,
        noinline owner: ViewModelOwnerDefinition = { from(this, this) },
        noinline parameters: ParametersDefinition? = null,
): Lazy<T> {
    return lazy(LazyThreadSafetyMode.NONE) {
        getViewModel(qualifier, state, owner, parameters)
    }
}

In Fragment, both viewModel and sharedViewModel works fine.

private val viewModel by viewModel<SearchViewModel>()
private val mainViewModel by sharedViewModel<MainViewModel>()

Question: What is the best way to inject ViewModel in Activity with Koin 2.2.0+ version?

score 20 · Accepted Answer · answered Nov 22 '20 at 11:13

20

I added this manually, and it works fine.

import org.koin.androidx.viewmodel.ext.android.viewModel

answered Nov 22 '20 at 11:13

Stanley Ko

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Saved my day. Thank you. Tried may ways but this helped at last as there was no other implementation issue. – Chintan Rathod Aug 03 '22 at 10:50
Can't use it in unit Test class. Any idea? – Viks Aug 15 '22 at 08:17

score 0 · Answer 2 · answered Jul 30 '21 at 21:03

I was missing the koin-android dependency:

// Koin for the dependencies injections
def koin_version = "3.1.2"
implementation "io.insert-koin:koin-core:$koin_version"
implementation "io.insert-koin:koin-test:$koin_version"
implementation "io.insert-koin:koin-android:$koin_version"
implementation "io.insert-koin:koin-core-ext:$koin_version"

Koin 2.2.1 : I cannot use "by viewModel" in Activity

2 Answers2