ViewModelProvider

open class ViewModelProvider
kotlin.Any
   ↳ androidx.lifecycle.ViewModelProvider

An utility class that provides ViewModels for a scope.

Default ViewModelProvider for an Activity or a Fragment can be obtained from androidx.lifecycle.ViewModelProviders class.

Summary

Nested classes
open

Factory which may create AndroidViewModel and ViewModel, which have an empty constructor.

abstract

Implementations of Factory interface are responsible to instantiate ViewModels.

open

Simple factory, which calls empty constructor on the give class.

Public constructors

Creates ViewModelProvider, which will create ViewModels via the given Factory and retain them in a store of the given ViewModelStoreOwner.

Creates ViewModelProvider, which will create ViewModels via the given Factory and retain them in the given store.

Public methods
open T
get(modelClass: Class<T>)

Returns an existing ViewModel or creates a new one in the scope (usually, a fragment or an activity), associated with this ViewModelProvider.

open T
get(key: String, modelClass: Class<T>)

Returns an existing ViewModel or creates a new one in the scope (usually, a fragment or an activity), associated with this ViewModelProvider.

Extension functions
From androidx.lifecycle
VM

Returns an existing ViewModel or creates a new one in the scope (usually, a fragment or an activity), associated with this ViewModelProvider.

Public constructors

<init>

ViewModelProvider(owner: ViewModelStoreOwner, factory: ViewModelProvider.Factory)

Creates ViewModelProvider, which will create ViewModels via the given Factory and retain them in a store of the given ViewModelStoreOwner.

Parameters
owner ViewModelStoreOwner: a ViewModelStoreOwner whose ViewModelStore will be used to retain ViewModels
factory ViewModelStoreOwner: a Factory which will be used to instantiate new ViewModels

<init>

ViewModelProvider(store: ViewModelStore, factory: ViewModelProvider.Factory)

Creates ViewModelProvider, which will create ViewModels via the given Factory and retain them in the given store.

Parameters
store ViewModelStore: ViewModelStore where ViewModels will be stored.
factory ViewModelStore: factory a Factory which will be used to instantiate new ViewModels

Public methods

get

open fun <T : ViewModel!> get(modelClass: Class<T>): T

Returns an existing ViewModel or creates a new one in the scope (usually, a fragment or an activity), associated with this ViewModelProvider.

The created ViewModel is associated with the given scope 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).

Parameters
modelClass Class<T>: The class of the ViewModel to create an instance of it if it is not present.
<T> Class<T>: The type parameter for the ViewModel.
Return
T: A ViewModel that is an instance of the given type T.

get

open fun <T : ViewModel!> get(key: String, modelClass: Class<T>): T

Returns an existing ViewModel or creates a new one in the scope (usually, a fragment or an activity), associated with this ViewModelProvider.

The created ViewModel is associated with the given scope 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).

Parameters
key String: The key to use to identify the ViewModel.
modelClass String: The class of the ViewModel to create an instance of it if it is not present.
<T> String: The type parameter for the ViewModel.
Return
T: A ViewModel that is an instance of the given type T.