I have a class that implements an interface
interface Sample {
fun a()
}
class StandardSample @Inject constructor() : Sample {
override fun a() {
}
}
I have a module for this class:
@Module
@InstallIn(ViewModelComponent::class)
interface SampleModule {
@Binds
fun bindSample(sample: StandardSample) : Sample
}
I use this class in a ViewModel:
@HiltViewModel
class BlankViewModel @Inject constructor(sample: Sample) : ViewModel() {
fun a() {
}
}
The viewmodel is initialized in a fragment like this:
private val viewModel: BlankViewModel by hiltNavGraphViewModels(R.id.main_navigation)
And it works. However, as far as I'm aware, if I initialize it this way, the ViewModel is scoped to the navigation graph. I want the ViewModel to be destroyed alongside with the fragment it was called from. To achieve that, I wanted to use
@AndroidEntryPoint
class BlankFragment : Fragment() {
private val viewModel : BlankViewModel by viewModels()
However, this led to an error: Cannot create an instance of class *KeyNotesViewModel as soon as I open the fragment.
How do I initialize a ViewModel scoped to a fragment using Hilt?
The stacktrace:
FATAL EXCEPTION: main
Process: com.example.greatapp, PID: 26166
java.lang.RuntimeException: Cannot create an instance of class com.example.greatapp.BlankViewModel
at androidx.lifecycle.ViewModelProvider$NewInstanceFactory.create(ViewModelProvider.kt:204)
at androidx.lifecycle.ViewModelProvider$AndroidViewModelFactory.create(ViewModelProvider.kt:324)
at androidx.lifecycle.ViewModelProvider$AndroidViewModelFactory.create(ViewModelProvider.kt:306)
at androidx.lifecycle.ViewModelProvider$AndroidViewModelFactory.create(ViewModelProvider.kt:280)
at androidx.lifecycle.SavedStateViewModelFactory.create(SavedStateViewModelFactory.kt:128)
at androidx.lifecycle.ViewModelProvider.get(ViewModelProvider.kt:187)
at androidx.lifecycle.ViewModelProvider.get(ViewModelProvider.kt:153)
at androidx.lifecycle.ViewModelLazy.getValue(ViewModelLazy.kt:53)
at androidx.lifecycle.ViewModelLazy.getValue(ViewModelLazy.kt:35)
at com.example.greatapp.BlankFragment.getViewModel(BlankFragment.kt:14)
at com.example.greatapp.BlankFragment.onViewCreated(BlankFragment.kt:25)
at androidx.fragment.app.Fragment.performViewCreated(Fragment.java:3147)
at androidx.fragment.app.FragmentStateManager.createView(FragmentStateManager.java:588)
at androidx.fragment.app.FragmentStateManager.moveToExpectedState(FragmentStateManager.java:272)
at androidx.fragment.app.FragmentStore.moveToExpectedState(FragmentStore.java:114)
at androidx.fragment.app.FragmentManager.moveToState(FragmentManager.java:1455)
at androidx.fragment.app.FragmentManager.dispatchStateChange(FragmentManager.java:3034)
at androidx.fragment.app.FragmentManager.dispatchViewCreated(FragmentManager.java:2945)
at androidx.fragment.app.Fragment.performViewCreated(Fragment.java:3148)
at androidx.fragment.app.FragmentStateManager.createView(FragmentStateManager.java:588)
at androidx.fragment.app.FragmentStateManager.moveToExpectedState(FragmentStateManager.java:272)
at androidx.fragment.app.FragmentStore.moveToExpectedState(FragmentStore.java:114)
at androidx.fragment.app.FragmentManager.moveToState(FragmentManager.java:1455)
at androidx.fragment.app.FragmentManager.dispatchStateChange(FragmentManager.java:3034)
at androidx.fragment.app.FragmentManager.dispatchActivityCreated(FragmentManager.java:2952)
at androidx.fragment.app.FragmentController.dispatchActivityCreated(FragmentController.java:263)
at androidx.fragment.app.FragmentActivity.onStart(FragmentActivity.java:350)
at androidx.appcompat.app.AppCompatActivity.onStart(AppCompatActivity.java:251)
at android.app.Instrumentation.callActivityOnStart(Instrumentation.java:1425)
at android.app.Activity.performStart(Activity.java:7825)
at android.app.ActivityThread.handleStartActivity(ActivityThread.java:3294)
at android.app.servertransaction.TransactionExecutor.performLifecycleSequence(TransactionExecutor.java:221)
at android.app.servertransaction.TransactionExecutor.cycleToPath(TransactionExecutor.java:201)
at android.app.servertransaction.TransactionExecutor.executeLifecycleState(TransactionExecutor.java:173)
at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:97)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2016)
at android.os.Handler.dispatchMessage(Handler.java:107)
at android.os.Looper.loop(Looper.java:214)
at android.app.ActivityThread.main(ActivityThread.java:7356)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:492)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:930)
Caused by: java.lang.NoSuchMethodException: com.example.greatapp.BlankViewModel.<init> []
at java.lang.Class.getConstructor0(Class.java:2332)
at java.lang.Class.getDeclaredConstructor(Class.java:2170)
at androidx.lifecycle.ViewModelProvider$NewInstanceFactory.create(ViewModelProvider.kt:202)
at androidx.lifecycle.ViewModelProvider$AndroidViewModelFactory.create(ViewModelProvider.kt:324)
at androidx.lifecycle.ViewModelProvider$AndroidViewModelFactory.create(ViewModelProvider.kt:306)
at androidx.lifecycle.ViewModelProvider$AndroidViewModelFactory.create(ViewModelProvider.kt:280)
at androidx.lifecycle.SavedStateViewModelFactory.create(SavedStateViewModelFactory.kt:128)
at androidx.lifecycle.ViewModelProvider.get(ViewModelProvider.kt:187)
at androidx.lifecycle.ViewModelProvider.get(ViewModelProvider.kt:153)
at androidx.lifecycle.ViewModelLazy.getValue(ViewModelLazy.kt:53)
at androidx.lifecycle.ViewModelLazy.getValue(ViewModelLazy.kt:35)
at com.example.greatapp.BlankFragment.getViewModel(BlankFragment.kt:14)
at com.example.greatapp.BlankFragment.onViewCreated(BlankFragment.kt:25)
at androidx.fragment.app.Fragment.performViewCreated(Fragment.java:3147)
at androidx.fragment.app.FragmentStateManager.createView(FragmentStateManager.java:588)
at androidx.fragment.app.FragmentStateManager.moveToExpectedState(FragmentStateManager.java:272)
at androidx.fragment.app.FragmentStore.moveToExpectedState(FragmentStore.java:114)
at androidx.fragment.app.FragmentManager.moveToState(FragmentManager.java:1455)
at androidx.fragment.app.FragmentManager.dispatchStateChange(FragmentManager.java:3034)
at androidx.fragment.app.FragmentManager.dispatchViewCreated(FragmentManager.java:2945)
at androidx.fragment.app.Fragment.performViewCreated(Fragment.java:3148)
at androidx.fragment.app.FragmentStateManager.createView(FragmentStateManager.java:588)
at androidx.fragment.app.FragmentStateManager.moveToExpectedState(FragmentStateManager.java:272)
at androidx.fragment.app.FragmentStore.moveToExpectedState(FragmentStore.java:114)
at androidx.fragment.app.FragmentManager.moveToState(FragmentManager.java:1455)
at androidx.fragment.app.FragmentManager.dispatchStateChange(FragmentManager.java:3034)
at androidx.fragment.app.FragmentManager.dispatchActivityCreated(FragmentManager.java:2952)
at androidx.fragment.app.FragmentController.dispatchActivityCreated(FragmentController.java:263)
at androidx.fragment.app.FragmentActivity.onStart(FragmentActivity.java:350)
at androidx.appcompat.app.AppCompatActivity.onStart(AppCompatActivity.java:251)
at android.app.Instrumentation.callActivityOnStart(Instrumentation.java:1425)
at android.app.Activity.performStart(Activity.java:7825)
at android.app.ActivityThread.handleStartActivity(ActivityThread.java:3294)
at android.app.servertransaction.TransactionExecutor.performLifecycleSequence(TransactionExecutor.java:221)
at android.app.servertransaction.TransactionExecutor.cycleToPath(TransactionExecutor.java:201)
at android.app.servertransaction.TransactionExecutor.executeLifecycleState(TransactionExecutor.java:173)
at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:97)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2016)
at android.os.Handler.dispatchMessage(Handler.java:107)
at android.os.Looper.loop(Looper.java:214)
at android.app.ActivityThread.main(ActivityThread.java:7356)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:492)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:930)