LoaderManager
abstract class LoaderManager
kotlin.Any | |
↳ | androidx.loader.app.LoaderManager |
Static library support version of the framework's android.app.LoaderManager
. Used to write apps that run on platforms prior to Android 3.0. When running on Android 3.0 or above, this implementation is still used; it does not try to switch to the framework's implementation. See the framework SDK documentation for a class overview.
Your activity must derive from androidx.fragment.app.FragmentActivity
to use this.
Summary
Nested classes | |
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abstract |
Callback interface for a client to interact with the manager. |
Public constructors | |
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<init>() Static library support version of the framework's |
Public methods | |
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abstract Unit |
destroyLoader(id: Int) Stops and removes the loader with the given ID. |
abstract Unit |
dump(prefix: String!, fd: FileDescriptor!, writer: PrintWriter!, args: Array<String!>!) Print the LoaderManager's state into the given stream. |
open static Unit |
enableDebugLogging(enabled: Boolean) Control whether the framework's internal loader manager debugging logs are turned on. |
open static LoaderManager |
getInstance(@NonNull owner: T) Gets a LoaderManager associated with the given owner, such as a |
abstract Loader<D>? |
Return the Loader with the given id or null if no matching Loader is found. |
open Boolean |
Returns true if any loaders managed are currently running and have not returned data to the application yet. |
abstract Loader<D> |
initLoader(id: Int, @Nullable args: Bundle?, @NonNull callback: LoaderManager.LoaderCallbacks<D>) Ensures a loader is initialized and active. |
abstract Unit |
Mark all Loaders associated with this LoaderManager for redelivery of their current data (if any), waiting for the next time the Loader is started if it is currently stopped. |
abstract Loader<D> |
restartLoader(id: Int, @Nullable args: Bundle?, @NonNull callback: LoaderManager.LoaderCallbacks<D>) Starts a new or restarts an existing |
Public constructors
<init>
LoaderManager()
Static library support version of the framework's android.app.LoaderManager
. Used to write apps that run on platforms prior to Android 3.0. When running on Android 3.0 or above, this implementation is still used; it does not try to switch to the framework's implementation. See the framework SDK documentation for a class overview.
Your activity must derive from androidx.fragment.app.FragmentActivity
to use this.
Public methods
destroyLoader
@MainThread abstract fun destroyLoader(id: Int): Unit
Stops and removes the loader with the given ID. If this loader had previously reported data to the client through LoaderCallbacks#onLoadFinished(Loader, Object)
, a call will be made to LoaderCallbacks#onLoaderReset(Loader)
.
Must be called from the process's main thread.
dump
abstract fundump(
prefix: String!,
fd: FileDescriptor!,
writer: PrintWriter!,
args: Array<String!>!
): Unit
Deprecated: Use enableDebugLogging(boolean)
to understand the series of operations performed by LoaderManager.
Print the LoaderManager's state into the given stream.
Parameters | |
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prefix |
String!: Text to print at the front of each line. |
fd |
FileDescriptor!: The raw file descriptor that the dump is being sent to. |
writer |
PrintWriter!: A PrintWriter to which the dump is to be set. |
args |
Array<String!>!: Additional arguments to the dump request. |
enableDebugLogging
open static fun enableDebugLogging(enabled: Boolean): Unit
Control whether the framework's internal loader manager debugging logs are turned on. If enabled, you will see output in logcat as the framework performs loader operations.
getInstance
@NonNull open static fun <T> getInstance(@NonNull owner: T): LoaderManager where T : LifecycleOwner!, T : ViewModelStoreOwner!
Gets a LoaderManager associated with the given owner, such as a androidx.fragment.app.FragmentActivity
or androidx.fragment.app.Fragment
.
Parameters | |
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owner |
T: The owner that should be used to create the returned LoaderManager |
<T> |
A class that maintains its own android.arch.lifecycle.Lifecycle and android.arch.lifecycle.ViewModelStore. For instance, androidx.fragment.app.FragmentActivity or androidx.fragment.app.Fragment . |
Return | |
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LoaderManager |
A valid LoaderManager |
getLoader
@Nullable abstract fun <D : Any!> getLoader(id: Int): Loader<D>?
Return the Loader with the given id or null if no matching Loader is found.
hasRunningLoaders
open fun hasRunningLoaders(): Boolean
Returns true if any loaders managed are currently running and have not returned data to the application yet.
initLoader
@MainThread @NonNull abstract fun <D : Any!> initLoader(
id: Int,
@Nullable args: Bundle?,
@NonNull callback: LoaderManager.LoaderCallbacks<D>
): Loader<D>
Ensures a loader is initialized and active. If the loader doesn't already exist, one is created and (if the activity/fragment is currently started) starts the loader. Otherwise the last created loader is re-used.
In either case, the given callback is associated with the loader, and will be called as the loader state changes. If at the point of call the caller is in its started state, and the requested loader already exists and has generated its data, then callback LoaderCallbacks#onLoadFinished
will be called immediately (inside of this function), so you must be prepared for this to happen.
Must be called from the process's main thread.
Parameters | |
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id |
Int: A unique identifier for this loader. Can be whatever you want. Identifiers are scoped to a particular LoaderManager instance. |
args |
Bundle?: Optional arguments to supply to the loader at construction. If a loader already exists (a new one does not need to be created), this parameter will be ignored and the last arguments continue to be used. |
callback |
LoaderManager.LoaderCallbacks<D>: Interface the LoaderManager will call to report about changes in the state of the loader. Required. |
markForRedelivery
abstract fun markForRedelivery(): Unit
Mark all Loaders associated with this LoaderManager for redelivery of their current data (if any), waiting for the next time the Loader is started if it is currently stopped. In cases where no data has yet been delivered, this is effectively a no-op. In cases where data has already been delivered via LoaderCallbacks#onLoadFinished(Loader, Object)
, this will ensure that LoaderCallbacks#onLoadFinished(Loader, Object)
is called again with the same data.
Call this only if you are implementing a LifecycleOwner
where the views/elements that developers are likely to use in LoaderCallbacks#onLoadFinished(Loader, Object)
can be created and destroyed multiple times without the LifecycleOwner
itself being destroyed. Call this when the views/elements are being destroyed to ensure that the data is redelivered upon recreation.
restartLoader
@MainThread @NonNull abstract fun <D : Any!> restartLoader(
id: Int,
@Nullable args: Bundle?,
@NonNull callback: LoaderManager.LoaderCallbacks<D>
): Loader<D>
Starts a new or restarts an existing android.content.Loader
in this manager, registers the callbacks to it, and (if the activity/fragment is currently started) starts loading it. If a loader with the same id has previously been started it will automatically be destroyed when the new loader completes its work. The callback will be delivered before the old loader is destroyed.
Must be called from the process's main thread.
Parameters | |
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id |
Int: A unique identifier for this loader. Can be whatever you want. Identifiers are scoped to a particular LoaderManager instance. |
args |
Bundle?: Optional arguments to supply to the loader at construction. |
callback |
LoaderManager.LoaderCallbacks<D>: Interface the LoaderManager will call to report about changes in the state of the loader. Required. |