CreationExtras
Known direct subclasses
CreationExtras.Empty

An empty read-only CreationExtras.
MutableCreationExtras

A modifiable CreationExtras that holds pairs of CreationExtras.Key and Any, allowing efficient value retrieval for each key.

A map-like object holding pairs of CreationExtras.Key and Any, enabling efficient value retrieval for each key. Each key in CreationExtras is unique, storing only one value per key.

CreationExtras is used in ViewModelProvider.Factory.create to provide extra information to the Factory. This makes Factory implementations stateless, simplifying factory injection by not requiring all information at construction time.

This abstract class supports read-only access; use MutableCreationExtras for read-write access.

Summary

Nested types

An empty read-only CreationExtras.
interface CreationExtras.Key<T : Any?>

Key for the elements of CreationExtras.

Public companion functions
inline CreationExtras.Key<T>
<T : Any?> Key()

Returns an unique Key to be associated with an extra.
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Public functions
open operator Boolean
equals(other: Any?)

Compares the specified object with this CreationExtras for equality.
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abstract operator T?
<T : Any?> get(key: CreationExtras.Key<T>)

Returns the value to which the specified key is associated, or null if this CreationExtras contains no mapping for the key.
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open Int

Returns the hash code value for this CreationExtras.
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open String

Returns a string representation of this CreationExtras.
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Extension functions
operator Boolean

Checks if the CreationExtras contains the given key.
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operator MutableCreationExtras

Creates a new read-only CreationExtras by replacing or adding entries to this extras from another creationExtras.
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SavedStateHandle

Creates SavedStateHandle that can be used in your ViewModels
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Public companion functions

Key

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inline fun <T : Any?> Key(): CreationExtras.Key<T>

Returns an unique Key to be associated with an extra.

Public functions

equals

Cmn 
open operator fun equals(other: Any?): Boolean

Compares the specified object with this CreationExtras for equality.

get

Cmn
Added in 2.5.0
abstract operator fun <T : Any?> get(key: CreationExtras.Key<T>): T?

Returns the value to which the specified key is associated, or null if this CreationExtras contains no mapping for the key.

hashCode

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open fun hashCode(): Int

Returns the hash code value for this CreationExtras.

toString

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open fun toString(): String

Returns a string representation of this CreationExtras. The string representation consists of a list of key-value mappings in the order returned by the CreationExtras's iterator.

Extension functions

contains

Cmn 
operator fun CreationExtras.contains(key: CreationExtras.Key<*>): Boolean

Checks if the CreationExtras contains the given key.

This method allows to use the key in creationExtras syntax for checking whether an key is contained in the CreationExtras.

plus

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operator fun CreationExtras.plus(creationExtras: CreationExtras): MutableCreationExtras

Creates a new read-only CreationExtras by replacing or adding entries to this extras from another creationExtras.

The returned CreationExtras preserves the entry iteration order of the original CreationExtras.

Those entries of another creationExtras that are missing in this extras are iterated in the end in the order of that creationExtras.

createSavedStateHandle

Cmn 
@MainThread
fun CreationExtras.createSavedStateHandle(): SavedStateHandle

Creates SavedStateHandle that can be used in your ViewModels

This function requires enableSavedStateHandles call during the component initialization. Latest versions of androidx components like ComponentActivity, Fragment, NavBackStackEntry makes this call automatically.

This CreationExtras must contain SAVED_STATE_REGISTRY_OWNER_KEY, VIEW_MODEL_STORE_OWNER_KEY and VIEW_MODEL_KEY.

Throws
kotlin.IllegalArgumentException

if this CreationExtras are missing required keys: ViewModelStoreOwnerKey, SavedStateRegistryOwnerKey, VIEW_MODEL_KEY