SavedStateRegistry
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class SavedStateRegistry : SavedStateProvider, SavedStateRestorer
Registry for components that consume and contribute to saved state.
Use this registry to save and restore component state across process death or recreation.
Summary
Nested types |
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interface SavedStateRegistry.AutoRecreatedThis interface is deprecated. `AutoRecreated` is deprecated. |
fun interface SavedStateRegistry.SavedStateProvider : SavedStateProviderContributes to the saved state. |
Public constructors |
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Creates an empty |
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SavedStateRegistry(initialState: Bundle)Creates a |
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SavedStateRegistry(initialState: SavedState)Creates a |
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Public functions |
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SavedState? |
Consumes the saved state previously supplied by a |
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SavedStateRegistry.SavedStateProvider? |
getSavedStateProvider(key: String)Returns the |
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Unit |
@MainThreadRegisters a |
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open Unit |
restoreState(savedState: Bundle?)Called to restore the state of a component. |
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open Unit |
restoreState(savedState: SavedState?)Called to restore the state of a component. |
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Unit |
This function is deprecated. `runOnNextRecreation` is deprecated. |
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open SavedState |
Called to retrieve the state from a component before it is killed so the state can be retrieved later from |
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Unit |
Unregisters a component previously registered with the given |
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Public properties |
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Boolean |
Returns |
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Public constructors
SavedStateRegistry
SavedStateRegistry(initialState: Bundle)
Creates a SavedStateRegistry initialized with initialState.
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initialState: Bundle |
The initial saved state to restore from. |
SavedStateRegistry
SavedStateRegistry(initialState: SavedState)
Creates a SavedStateRegistry initialized with initialState.
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initialState: SavedState |
The initial saved state to restore from. |
Public functions
consumeRestoredStateForKey
@MainThread
fun consumeRestoredStateForKey(key: String): SavedState?
Consumes the saved state previously supplied by a SavedStateProvider registered with the given key.
If the registered SavedStateProvider implements SavedStateRestorer, the state is restored automatically during restoration, and calls to this method with the same key return null.
This call clears the internal reference to the returned saved state. Subsequent calls with the same key return null.
All unconsumed values are preserved during state saving.
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key: String |
The key with which the |
| Returns | |
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SavedState? |
The previously saved state, or |
getSavedStateProvider
fun getSavedStateProvider(key: String): SavedStateRegistry.SavedStateProvider?
Returns the SavedStateProvider previously registered with registerSavedStateProvider, or null if no provider has been registered with the given key.
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key: String |
The key used to register the |
registerSavedStateProvider
@MainThread
fun registerSavedStateProvider(
key: String,
provider: SavedStateRegistry.SavedStateProvider
): Unit
Registers a SavedStateProvider with the given key.
This SavedStateProvider will be called during state saving. The returned state is associated with the given key and can be consumed after restoration via consumeRestoredStateForKey.
If the registered provider implements SavedStateRestorer, its SavedStateRestorer.restoreState method is automatically invoked during state restoration, or immediately if state has already been restored.
If a provider was already registered with the given key, it is replaced with the new provider.
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key: String |
The key to associate with the provider. |
provider: SavedStateRegistry.SavedStateProvider |
The |
restoreState
open fun restoreState(savedState: Bundle?): Unit
Called to restore the state of a component.
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savedState: Bundle? |
The |
restoreState
open fun restoreState(savedState: SavedState?): Unit
Called to restore the state of a component.
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savedState: SavedState? |
The |
runOnNextRecreation
@MainThread
funrunOnNextRecreation(clazz: Class<SavedStateRegistry.AutoRecreated>): Unit
Executes the given class when the owning component restarted.
The given class will be automatically instantiated via default constructor and method AutoRecreated.onRecreated will be called. It is called as part of dispatching of androidx.lifecycle.Lifecycle.Event.ON_CREATE event.
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clazz: Class<SavedStateRegistry.AutoRecreated> |
that will need to be instantiated on the next component recreation |
| Throws | |
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IllegalArgumentException |
if you try to call if after |
saveState
open fun saveState(): SavedState
Called to retrieve the state from a component before it is killed so the state can be retrieved later from SavedStateRegistry.consumeRestoredStateForKey.
| Returns | |
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SavedState |
The |
unregisterSavedStateProvider
@MainThread
fun unregisterSavedStateProvider(key: String): Unit
Unregisters a component previously registered with the given key.
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key: String |
The key with which the component was previously registered. |
Public properties
isRestored
val isRestored: Boolean
Returns true if state has been restored and can be safely consumed with consumeRestoredStateForKey, false otherwise.