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.ViewModel
import androidx.lifecycle.ViewModelProvider
import androidx.lifecycle.viewmodel.compose.LocalViewModelStoreOwner
import androidx.lifecycle.viewmodel.compose.viewModel
import androidx.navigation.NavBackStackEntry
import androidx.navigation.NavController
import kotlin.reflect.KClass
/**
* 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
*/
@Composable
inline fun <reified VM : ViewModel> hiltViewModel(): VM {
val owner = LocalViewModelStoreOwner.current
return if (owner is NavBackStackEntry) {
hiltViewModel(VM::class, owner)
} else {
viewModel()
}
}
/**
* 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.
*/
@Deprecated(
message = "Use hiltViewModel() instead.",
replaceWith = ReplaceWith("hiltViewModel()"),
)
@Composable
inline fun <reified VM : ViewModel> hiltNavGraphViewModel() = hiltViewModel<VM>()
/**
* 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 [NavController] back stack.
*
* @param backStackEntry The entry of a [NavController] back stack.
*
* @sample androidx.hilt.navigation.compose.samples.NestedNavComposable
*/
@Composable
inline fun <reified VM : ViewModel> hiltViewModel(backStackEntry: NavBackStackEntry) =
hiltViewModel(VM::class, backStackEntry)
/**
* 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 [NavController] back stack.
*
* @param backStackEntry The entry of a [NavController] back stack.
*/
@Deprecated(
message = "Use hiltViewModel(NavBackStackEntry) instead.",
replaceWith = ReplaceWith("hiltViewModel(backStackEntry)"),
)
@Composable
inline fun <reified VM : ViewModel> hiltNavGraphViewModel(backStackEntry: NavBackStackEntry) =
hiltViewModel<VM>(backStackEntry)
/**
* 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 [NavController] back stack.
*
* @param route route of a destination that exists on the [NavController] back stack.
*/
@Deprecated(
message = "Use hiltViewModel(NavBackStackEntry) in combination with " +
"NavController#getBackStackEntry(String). This API will be removed in a future version.",
replaceWith = ReplaceWith("hiltViewModel(this.getBackStackEntry(route))"),
level = DeprecationLevel.ERROR
)
@Composable
inline fun <reified VM : ViewModel> NavController.hiltNavGraphViewModel(route: String) =
hiltViewModel<VM>(this.getBackStackEntry(route))
@Composable
@PublishedApi
internal fun <VM : ViewModel> hiltViewModel(
kClass: KClass<VM>,
backStackEntry: NavBackStackEntry
): VM {
val viewModelFactory = HiltViewModelFactory(
context = LocalContext.current,
navBackStackEntry = backStackEntry
)
return ViewModelProvider(backStackEntry, viewModelFactory).get(kClass.java)
}