Added in API level 11
Deprecated in API level 28

Summary: Ctors | Methods | Protected Methods | Inherited Methods

CursorLoader

Kotlin |Java

public class CursorLoader
extends AsyncTaskLoader<Cursor>

java.lang.Object
↳	android.content.Loader<android.database.Cursor>
	↳	android.content.AsyncTaskLoader<android.database.Cursor>
		↳	android.content.CursorLoader

This class was deprecated in API level 28.
Use the Support Library CursorLoader

A loader that queries the ContentResolver and returns a Cursor. This class implements the Loader protocol in a standard way for querying cursors, building on AsyncTaskLoader to perform the cursor query on a background thread so that it does not block the application's UI.

A CursorLoader must be built with the full information for the query to perform, either through the CursorLoader(android.content.Context, android.net.Uri, java.lang.String[], java.lang.String, java.lang.String[], java.lang.String) or creating an empty instance with CursorLoader(android.content.Context) and filling in the desired parameters with setUri(android.net.Uri), setSelection(java.lang.String), setSelectionArgs(java.lang.String[]), setSortOrder(java.lang.String), and setProjection(java.lang.String[]).

Summary

Public constructors
`CursorLoader(Context context)` Creates an empty unspecified CursorLoader.
`CursorLoader(Context context, Uri uri, String[] projection, String selection, String[] selectionArgs, String sortOrder)` Creates a fully-specified CursorLoader.

Public methods
`void`	`cancelLoadInBackground()` Called on the main thread to abort a load in progress.
`void`	`deliverResult(Cursor cursor)` Sends the result of the load to the registered listener.
`void`	`dump(String prefix, FileDescriptor fd, PrintWriter writer, String[] args)` Print the Loader's state into the given stream.
`String[]`	`getProjection()`
`String`	`getSelection()`
`String[]`	`getSelectionArgs()`
`String`	`getSortOrder()`
`Uri`	`getUri()`
`Cursor`	`loadInBackground()` Called on a worker thread to perform the actual load and to return the result of the load operation.
`void`	`onCanceled(Cursor cursor)` Called if the task was canceled before it was completed.
`void`	`setProjection(String[] projection)`
`void`	`setSelection(String selection)`
`void`	`setSelectionArgs(String[] selectionArgs)`
`void`	`setSortOrder(String sortOrder)`
`void`	`setUri(Uri uri)`

Protected methods
`void`	`onReset()` Subclasses must implement this to take care of resetting their loader, as per `reset()`.
`void`	`onStartLoading()` Starts an asynchronous load of the data.
`void`	`onStopLoading()` Must be called from the UI thread

Inherited methods

From class


        
          android.content.AsyncTaskLoader

`void`	`cancelLoadInBackground()` Called on the main thread to abort a load in progress.
`void`	`dump(String prefix, FileDescriptor fd, PrintWriter writer, String[] args)` Print the Loader's state into the given stream.
`boolean`	`isLoadInBackgroundCanceled()` Returns true if the current invocation of `loadInBackground()` is being canceled.
`abstract Cursor`	`loadInBackground()` Called on a worker thread to perform the actual load and to return the result of the load operation.
`boolean`	`onCancelLoad()` Subclasses must implement this to take care of requests to `cancelLoad()`.
`void`	`onCanceled(Cursor data)` Called if the task was canceled before it was completed.
`void`	`onForceLoad()` Subclasses must implement this to take care of requests to `forceLoad()`.
`Cursor`	`onLoadInBackground()` Calls `loadInBackground()`.
`void`	`setUpdateThrottle(long delayMS)` Set amount to throttle updates by.

From class


        
          android.content.Loader

`void`	`abandon()` This function will normally be called for you automatically by `LoaderManager` when restarting a Loader.
`boolean`	`cancelLoad()` Attempt to cancel the current load task.
`void`	`commitContentChanged()` Commit that you have actually fully processed a content change that was returned by `takeContentChanged()`.
`String`	`dataToString(Cursor data)` For debugging, converts an instance of the Loader's data class to a string that can be printed.
`void`	`deliverCancellation()` Informs the registered `OnLoadCanceledListener` that the load has been canceled.
`void`	`deliverResult(Cursor data)` Sends the result of the load to the registered listener.
`void`	`dump(String prefix, FileDescriptor fd, PrintWriter writer, String[] args)` Print the Loader's state into the given stream.
`void`	`forceLoad()` Force an asynchronous load.
`Context`	`getContext()`
`int`	`getId()`
`boolean`	`isAbandoned()` Return whether this loader has been abandoned.
`boolean`	`isReset()` Return whether this load has been reset.
`boolean`	`isStarted()` Return whether this load has been started.
`void`	`onAbandon()` Subclasses implement this to take care of being abandoned.
`boolean`	`onCancelLoad()` Subclasses must implement this to take care of requests to `cancelLoad()`.
`void`	`onContentChanged()` Called when `ForceLoadContentObserver` detects a change.
`void`	`onForceLoad()` Subclasses must implement this to take care of requests to `forceLoad()`.
`void`	`onReset()` Subclasses must implement this to take care of resetting their loader, as per `reset()`.
`void`	`onStartLoading()` Subclasses must implement this to take care of loading their data, as per `startLoading()`.
`void`	`onStopLoading()` Subclasses must implement this to take care of stopping their loader, as per `stopLoading()`.
`void`	`registerListener(int id, OnLoadCompleteListener<Cursor> listener)` Registers a class that will receive callbacks when a load is complete.
`void`	`registerOnLoadCanceledListener(OnLoadCanceledListener<Cursor> listener)` Registers a listener that will receive callbacks when a load is canceled.
`void`	`reset()` This function will normally be called for you automatically by `LoaderManager` when destroying a Loader.
`void`	`rollbackContentChanged()` Report that you have abandoned the processing of a content change that was returned by `takeContentChanged()` and would like to rollback to the state where there is again a pending content change.
`final void`	`startLoading()` This function will normally be called for you automatically by `LoaderManager` when the associated fragment/activity is being started.
`void`	`stopLoading()` This function will normally be called for you automatically by `LoaderManager` when the associated fragment/activity is being stopped.
`boolean`	`takeContentChanged()` Take the current flag indicating whether the loader's content had changed while it was stopped.
`String`	`toString()` Returns a string representation of the object.
`void`	`unregisterListener(OnLoadCompleteListener<Cursor> listener)` Remove a listener that was previously added with `registerListener(int, OnLoadCompleteListener)`.
`void`	`unregisterOnLoadCanceledListener(OnLoadCanceledListener<Cursor> listener)` Unregisters a listener that was previously added with `registerOnLoadCanceledListener(OnLoadCanceledListener)`.

From class


        
          java.lang.Object

`Object`	`clone()` Creates and returns a copy of this object.
`boolean`	`equals(Object obj)` Indicates whether some other object is "equal to" this one.
`void`	`finalize()` Called by the garbage collector on an object when garbage collection determines that there are no more references to the object.
`final Class<?>`	`getClass()` Returns the runtime class of this `Object`.
`int`	`hashCode()` Returns a hash code value for the object.
`final void`	`notify()` Wakes up a single thread that is waiting on this object's monitor.
`final void`	`notifyAll()` Wakes up all threads that are waiting on this object's monitor.
`String`	`toString()` Returns a string representation of the object.
`final void`	`wait(long timeoutMillis, int nanos)` Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed.
`final void`	`wait(long timeoutMillis)` Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed.
`final void`	`wait()` Causes the current thread to wait until it is awakened, typically by being notified or interrupted.

Public constructors

CursorLoader

Added in API level 11

public CursorLoader (Context context)

Creates an empty unspecified CursorLoader. You must follow this with calls to setUri(android.net.Uri), setSelection(java.lang.String), etc to specify the query to perform.

Parameters
`context`	`Context`

CursorLoader

Added in API level 11

public CursorLoader (Context context, 
                Uri uri, 
                String[] projection, 
                String selection, 
                String[] selectionArgs, 
                String sortOrder)

Creates a fully-specified CursorLoader. See ContentResolver.query() for documentation on the meaning of the parameters. These will be passed as-is to that call.

Parameters
`context`	`Context`
`uri`	`Uri`
`projection`	`String`
`selection`	`String`
`selectionArgs`	`String`
`sortOrder`	`String`

Public methods

cancelLoadInBackground

Added in API level 16
Deprecated in API level 28

public void cancelLoadInBackground ()

Called on the main thread to abort a load in progress. Override this method to abort the current invocation of loadInBackground() that is running in the background on a worker thread. This method should do nothing if loadInBackground() has not started running or if it has already finished.

deliverResult

Added in API level 11

public void deliverResult (Cursor cursor)

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
`cursor`	`Cursor`: the result of the load

dump

Added in API level 11

public void dump (String prefix, 
                FileDescriptor fd, 
                PrintWriter writer, 
                String[] args)

Print the Loader's state into the given stream.

Parameters
`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`	`String`: Additional arguments to the dump request.

getProjection

Added in API level 11

public String[] getProjection ()

Returns
`String[]`

getSelection

Added in API level 11

public String getSelection ()

Returns
`String`

getSelectionArgs

Added in API level 11

public String[] getSelectionArgs ()

Returns
`String[]`

getSortOrder

Added in API level 11

public String getSortOrder ()

Returns
`String`

getUri

Added in API level 11

public Uri getUri ()

Returns
`Uri`

loadInBackground

Added in API level 11

public Cursor loadInBackground ()

Called on a worker thread to perform the actual load and to return the result of the load operation. Implementations should not deliver the result directly, but should return them from this method, which will eventually end up calling Loader.deliverResult(D) on the UI thread. If implementations need to process the results on the UI thread they may override Loader.deliverResult(D) and do so there. To support cancellation, this method should periodically check the value of isLoadInBackgroundCanceled() and terminate when it returns true. Subclasses may also override cancelLoadInBackground() to interrupt the load directly instead of polling isLoadInBackgroundCanceled(). When the load is canceled, this method may either return normally or throw OperationCanceledException. In either case, the Loader will call onCanceled(D) to perform post-cancellation cleanup and to dispose of the result object, if any.

Returns
`Cursor`	The result of the load operation.

onCanceled

Added in API level 11

public void onCanceled (Cursor cursor)

Called if the task was canceled before it was completed. Gives the class a chance to clean up post-cancellation and to properly dispose of the result.

Parameters
`cursor`	`Cursor`: The value that was returned by `loadInBackground()`, or null if the task threw `OperationCanceledException`.

setProjection

Added in API level 11

public void setProjection (String[] projection)

Parameters
`projection`	`String`

setSelection

Added in API level 11

public void setSelection (String selection)

Parameters
`selection`	`String`

setSelectionArgs

Added in API level 11

public void setSelectionArgs (String[] selectionArgs)

Parameters
`selectionArgs`	`String`

setSortOrder

Added in API level 11

public void setSortOrder (String sortOrder)

Parameters
`sortOrder`	`String`

setUri

Added in API level 11

public void setUri (Uri uri)

Parameters
`uri`	`Uri`

Protected methods

onReset

Added in API level 11

protected void onReset ()

Subclasses must implement this to take care of resetting their loader, as per reset(). This is not called by clients directly, but as a result of a call to reset(). This will always be called from the process's main thread.

onStartLoading

Added in API level 11

protected void onStartLoading ()

Starts an asynchronous load of the data. When the result is ready the callbacks will be called on the UI thread. If a previous load has been completed and is still valid the result may be passed to the callbacks immediately. Must be called from the UI thread

onStopLoading

Added in API level 11

protected void onStopLoading ()

Must be called from the UI thread