HiltViewModel.kt
/*
* Copyright 2021 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package androidx.hilt.navigation.compose
import androidx.compose.runtime.Composable
import androidx.compose.ui.platform.LocalContext
import androidx.hilt.navigation.HiltViewModelFactory
import androidx.lifecycle.HasDefaultViewModelProviderFactory
import androidx.lifecycle.ViewModel
import androidx.lifecycle.ViewModelProvider
import androidx.lifecycle.ViewModelStoreOwner
import androidx.lifecycle.viewmodel.CreationExtras
import androidx.lifecycle.viewmodel.compose.LocalViewModelStoreOwner
import androidx.lifecycle.viewmodel.compose.viewModel
import dagger.hilt.android.internal.lifecycle.HiltViewModelFactory
import dagger.hilt.android.lifecycle.withCreationCallback
/**
* Returns an existing
* [HiltViewModel](https://dagger.dev/api/latest/dagger/hilt/android/lifecycle/HiltViewModel)
* -annotated [ViewModel] or creates a new one scoped to the current navigation graph present on
* the {@link NavController} back stack.
*
* If no navigation graph is currently present then the current scope will be used, usually, a
* fragment or an activity.
*
* @sample androidx.hilt.navigation.compose.samples.NavComposable
* @sample androidx.hilt.navigation.compose.samples.NestedNavComposable
*/
@Composable
inline fun <reified VM : ViewModel> hiltViewModel(
viewModelStoreOwner: ViewModelStoreOwner = checkNotNull(LocalViewModelStoreOwner.current) {
"No ViewModelStoreOwner was provided via LocalViewModelStoreOwner"
},
key: String? = null
): VM {
val factory = createHiltViewModelFactory(viewModelStoreOwner)
return viewModel(viewModelStoreOwner, key, factory = factory)
}
/**
* Returns an existing
* [HiltViewModel](https://dagger.dev/api/latest/dagger/hilt/android/lifecycle/HiltViewModel)
* -annotated [ViewModel] with an [@AssistedInject]-annotated constructor or creates a new one scoped to the current navigation graph present on
* the {@link NavController} back stack.
*
* If no navigation graph is currently present then the current scope will be used, usually, a
* fragment or an activity.
*
* @sample androidx.hilt.navigation.compose.samples.NavComposable
* @sample androidx.hilt.navigation.compose.samples.NestedNavComposable
*/
@Composable
inline fun <reified VM : ViewModel, reified VMF> hiltViewModel(
viewModelStoreOwner: ViewModelStoreOwner = checkNotNull(LocalViewModelStoreOwner.current) {
"No ViewModelStoreOwner was provided via LocalViewModelStoreOwner"
},
key: String? = null,
noinline creationCallback: (VMF) -> VM
): VM {
val factory = createHiltViewModelFactory(viewModelStoreOwner)
return viewModel(
viewModelStoreOwner = viewModelStoreOwner,
key = key,
factory = factory,
extras = viewModelStoreOwner.run {
if (this is HasDefaultViewModelProviderFactory) {
this.defaultViewModelCreationExtras.withCreationCallback(creationCallback)
} else {
CreationExtras.Empty.withCreationCallback(creationCallback)
}
}
)
}
@Composable
@PublishedApi
internal fun createHiltViewModelFactory(
viewModelStoreOwner: ViewModelStoreOwner
): ViewModelProvider.Factory? = if (viewModelStoreOwner is HasDefaultViewModelProviderFactory) {
HiltViewModelFactory(
context = LocalContext.current,
delegateFactory = viewModelStoreOwner.defaultViewModelProviderFactory
)
} else {
// Use the default factory provided by the ViewModelStoreOwner
// and assume it is an @AndroidEntryPoint annotated fragment or activity
null
}