Loader
open class Loader<D : Any!>
kotlin.Any | |
↳ | androidx.loader.content.Loader |
Static library support version of the framework's android.content.Loader
. 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.
Summary
Nested classes | |
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An implementation of a ContentObserver that takes care of connecting it to the Loader to have the loader re-load its data when the observer is told it has changed. |
|
abstract |
Interface that is implemented to discover when a Loader has been canceled before it finished loading its data. |
abstract |
Interface that is implemented to discover when a Loader has finished loading its data. |
Public constructors | |
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Stores away the application context associated with context. |
Public methods | |
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open Unit |
abandon() This function will normally be called for you automatically by |
open Boolean |
Attempt to cancel the current load task. |
open Unit |
Commit that you have actually fully processed a content change that was returned by |
open String |
dataToString(@Nullable data: D?) For debugging, converts an instance of the Loader's data class to a string that can be printed. |
open Unit |
Informs the registered |
open Unit |
deliverResult(@Nullable data: D?) Sends the result of the load to the registered listener. |
open Unit |
dump(prefix: String!, fd: FileDescriptor!, writer: PrintWriter!, args: Array<String!>!) Print the Loader's state into the given stream. |
open Unit |
Force an asynchronous load. |
open Context | |
open Int |
getId() |
open Boolean |
Return whether this loader has been abandoned. |
open Boolean |
isReset() Return whether this load has been reset. |
open Boolean |
Return whether this load has been started. |
open Unit |
Called when |
open Unit |
registerListener(id: Int, @NonNull listener: Loader.OnLoadCompleteListener<D>) Registers a class that will receive callbacks when a load is complete. |
open Unit |
registerOnLoadCanceledListener(@NonNull listener: Loader.OnLoadCanceledListener<D>) Registers a listener that will receive callbacks when a load is canceled. |
open Unit |
reset() This function will normally be called for you automatically by |
open Unit |
Report that you have abandoned the processing of a content change that was returned by |
Unit |
This function will normally be called for you automatically by |
open Unit |
This function will normally be called for you automatically by |
open Boolean |
Take the current flag indicating whether the loader's content had changed while it was stopped. |
open String |
toString() |
open Unit |
unregisterListener(@NonNull listener: Loader.OnLoadCompleteListener<D>) Remove a listener that was previously added with |
open Unit |
unregisterOnLoadCanceledListener(@NonNull listener: Loader.OnLoadCanceledListener<D>) Unregisters a listener that was previously added with |
Protected methods | |
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open Unit |
Subclasses implement this to take care of being abandoned. |
open Boolean |
Subclasses must implement this to take care of requests to |
open Unit |
Subclasses must implement this to take care of requests to |
open Unit |
onReset() Subclasses must implement this to take care of resetting their loader, as per |
open Unit |
Subclasses must implement this to take care of loading their data, as per |
open Unit |
Subclasses must implement this to take care of stopping their loader, as per |
Public constructors
<init>
Loader(@NonNull context: Context)
Stores away the application context associated with context. Since Loaders can be used across multiple activities it's dangerous to store the context directly; always use getContext()
to retrieve the Loader's Context, don't use the constructor argument directly. The Context returned by getContext
is safe to use across Activity instances.
Parameters | |
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context |
Context: used to retrieve the application context. |
Public methods
abandon
@MainThread open fun abandon(): Unit
This function will normally be called for you automatically by LoaderManager
when restarting a Loader. When using a Loader with LoaderManager
, you must not call this method yourself, or you will conflict with its management of the Loader. Tell the Loader that it is being abandoned. This is called prior to reset
to have it retain its current data but not report any new data.
Must be called from the process's main thread.
cancelLoad
@MainThread open fun cancelLoad(): Boolean
Attempt to cancel the current load task. Must be called on the main thread of the process.
Cancellation is not an immediate operation, since the load is performed in a background thread. If there is currently a load in progress, this method requests that the load be canceled, and notes this is the case; once the background thread has completed its work its remaining state will be cleared. If another load request comes in during this time, it will be held until the canceled load is complete.
Return | |
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Boolean |
Returns false if the task could not be canceled, typically because it has already completed normally, or because startLoading() hasn't been called; returns true otherwise. When true is returned, the task is still running and the OnLoadCanceledListener will be called when the task completes. |
commitContentChanged
open fun commitContentChanged(): Unit
Commit that you have actually fully processed a content change that was returned by takeContentChanged
. This is for use with rollbackContentChanged()
to handle situations where a load is cancelled. Call this when you have completely processed a load without it being cancelled.
dataToString
@NonNull open fun dataToString(@Nullable data: D?): String
For debugging, converts an instance of the Loader's data class to a string that can be printed. Must handle a null data.
deliverCancellation
@MainThread open fun deliverCancellation(): Unit
Informs the registered OnLoadCanceledListener
that the load has been canceled. Should only be called by subclasses. Must be called from the process's main thread.
deliverResult
@MainThread open fun deliverResult(@Nullable data: D?): Unit
Sends the result of the load to the registered listener. Should only be called by subclasses. Must be called from the process's main thread.
Parameters | |
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data |
D?: the result of the load |
dump
open fundump(
prefix: String!,
fd: FileDescriptor!,
writer: PrintWriter!,
args: Array<String!>!
): Unit
Deprecated: Consider using LoaderManager#enableDebugLogging(boolean)
to understand the series of operations performed by LoaderManager.
Print the Loader'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. |
forceLoad
@MainThread open fun forceLoad(): Unit
Force an asynchronous load. Unlike startLoading()
this will ignore a previously loaded data set and load a new one. This simply calls through to the implementation's onForceLoad()
. You generally should only call this when the loader is started -- that is, isStarted()
returns true.
Must be called from the process's main thread.
getContext
@NonNull open fun getContext(): Context
Return | |
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Context |
an application context retrieved from the Context passed to the constructor. |