ViewModel.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.lifecycle.viewmodel.compose
import androidx.compose.runtime.Composable
import androidx.lifecycle.ViewModel
import androidx.lifecycle.ViewModelProvider
import androidx.lifecycle.ViewModelStoreOwner
/**
* Returns an existing [ViewModel] or creates a new one in the given owner (usually, a fragment or
* an activity), defaulting to the owner provided by [LocalViewModelStoreOwner].
*
* The created [ViewModel] is associated with the given [viewModelStoreOwner] and will be retained
* as long as the owner is alive (e.g. if it is an activity, until it is
* finished or process is killed).
*
* @param viewModelStoreOwner The owner of the [ViewModel] that controls the scope and lifetime
* of the returned [ViewModel]. Defaults to using [LocalViewModelStoreOwner].
* @param key The key to use to identify the [ViewModel].
* @param factory The [ViewModelProvider.Factory] that should be used to create the [ViewModel]
* or null if you would like to use the default factory from the [LocalViewModelStoreOwner]
* @return A [ViewModel] that is an instance of the given [VM] type.
*/
@Suppress("MissingJvmstatic")
@Composable
public inline fun <reified VM : ViewModel> viewModel(
viewModelStoreOwner: ViewModelStoreOwner = checkNotNull(LocalViewModelStoreOwner.current) {
"No ViewModelStoreOwner was provided via LocalViewModelStoreOwner"
},
key: String? = null,
factory: ViewModelProvider.Factory? = null
): VM = viewModel(VM::class.java, viewModelStoreOwner, key, factory)
/**
* Returns an existing [ViewModel] or creates a new one in the scope (usually, a fragment or
* an activity)
*
* The created [ViewModel] is associated with the given [viewModelStoreOwner] and will be retained
* as long as the scope is alive (e.g. if it is an activity, until it is
* finished or process is killed).
*
* @param modelClass The class of the [ViewModel] to create an instance of it if it is not
* present.
* @param viewModelStoreOwner The scope that the created [ViewModel] should be associated with.
* @param key The key to use to identify the [ViewModel].
* @return A [ViewModel] that is an instance of the given [VM] type.
*/
@Suppress("MissingJvmstatic")
@Composable
public fun <VM : ViewModel> viewModel(
modelClass: Class<VM>,
viewModelStoreOwner: ViewModelStoreOwner = checkNotNull(LocalViewModelStoreOwner.current) {
"No ViewModelStoreOwner was provided via LocalViewModelStoreOwner"
},
key: String? = null,
factory: ViewModelProvider.Factory? = null
): VM = viewModelStoreOwner.get(modelClass, key, factory)
private fun <VM : ViewModel> ViewModelStoreOwner.get(
javaClass: Class<VM>,
key: String? = null,
factory: ViewModelProvider.Factory? = null
): VM {
val provider = if (factory != null) {
ViewModelProvider(this, factory)
} else {
ViewModelProvider(this)
}
return if (key != null) {
provider.get(key, javaClass)
} else {
provider.get(javaClass)
}
}