ViewModelProvider

open class ViewModelProvider


A utility class that provides ViewModels for a scope.

Default ViewModelProvider for an Activity or a Fragment can be obtained by passing it to the constructor: ViewModelProvider(myFragment)

Summary

Nested types

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

Implementations of Factory interface are responsible to instantiate ViewModels.

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

Public constructors

Creates ViewModelProvider.

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

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

Public functions

open operator T
@MainThread
<T : ViewModel> 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 operator T
@MainThread
<T : ViewModel> 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

inline 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

ViewModelProvider

Added in 2.2.0
ViewModelProvider(owner: ViewModelStoreOwner)

Creates ViewModelProvider. This will create ViewModels and retain them in a store of the given ViewModelStoreOwner.

This method will use the default factory if the owner implements HasDefaultViewModelProviderFactory. Otherwise, a NewInstanceFactory will be used.

ViewModelProvider

Added in 2.0.0
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: ViewModelProvider.Factory

a Factory which will be used to instantiate new ViewModels

ViewModelProvider

Added in 2.5.0
ViewModelProvider(
    store: ViewModelStore,
    factory: ViewModelProvider.Factory,
    defaultCreationExtras: CreationExtras = CreationExtras.Empty
)

Public functions

get

Added in 2.0.0
@MainThread
open operator 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.

Returns
T

A ViewModel that is an instance of the given type T.

Throws
java.lang.IllegalArgumentException

if the given modelClass is local or anonymous class.

get

Added in 2.0.0
@MainThread
open operator 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: Class<T>

The class of the ViewModel to create an instance of it if it is not present.

Returns
T

A ViewModel that is an instance of the given type T.

Extension functions

@MainThread
inline fun <VM : ViewModel> ViewModelProvider.get(): VM

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

See also
get

(Class)