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Added in API level 1

Filter

public abstract class Filter
extends Object

java.lang.Object
   ↳ android.widget.Filter


A filter constrains data with a filtering pattern.

Filters are usually created by Filterable classes.

Filtering operations performed by calling filter(CharSequence) or filter(CharSequence, android.widget.Filter.FilterListener) are performed asynchronously. When these methods are called, a filtering request is posted in a request queue and processed later. Any call to one of these methods will cancel any previous non-executed filtering request.

See also:

Summary

Nested classes

interface Filter.FilterListener

Listener used to receive a notification upon completion of a filtering operation. 

class Filter.FilterResults

Holds the results of a filtering operation. 

Public constructors

Filter()

Creates a new asynchronous filter.

Public methods

CharSequence convertResultToString(Object resultValue)

Converts a value from the filtered set into a CharSequence.

final void filter(CharSequence constraint)

Starts an asynchronous filtering operation.

final void filter(CharSequence constraint, Filter.FilterListener listener)

Starts an asynchronous filtering operation.

Protected methods

abstract Filter.FilterResults performFiltering(CharSequence constraint)

Invoked in a worker thread to filter the data according to the constraint.

abstract void publishResults(CharSequence constraint, Filter.FilterResults results)

Invoked in the UI thread to publish the filtering results in the user interface.

Inherited methods

From class java.lang.Object

Public constructors

Filter

Added in API level 1
Filter ()

Creates a new asynchronous filter.

Public methods

convertResultToString

Added in API level 1
CharSequence convertResultToString (Object resultValue)

Converts a value from the filtered set into a CharSequence. Subclasses should override this method to convert their results. The default implementation returns an empty String for null values or the default String representation of the value.

Parameters
resultValue Object: the value to convert to a CharSequence
Returns
CharSequence a CharSequence representing the value

filter

Added in API level 1
void filter (CharSequence constraint)

Starts an asynchronous filtering operation. Calling this method cancels all previous non-executed filtering requests and posts a new filtering request that will be executed later.

Parameters
constraint CharSequence: the constraint used to filter the data

See also:

filter

Added in API level 1
void filter (CharSequence constraint, 
                Filter.FilterListener listener)

Starts an asynchronous filtering operation. Calling this method cancels all previous non-executed filtering requests and posts a new filtering request that will be executed later.

Upon completion, the listener is notified.

Parameters
constraint CharSequence: the constraint used to filter the data
listener Filter.FilterListener: a listener notified upon completion of the operation

See also:

Protected methods

performFiltering

Added in API level 1
Filter.FilterResults performFiltering (CharSequence constraint)

Invoked in a worker thread to filter the data according to the constraint. Subclasses must implement this method to perform the filtering operation. Results computed by the filtering operation must be returned as a Filter.FilterResults that will then be published in the UI thread through publishResults(CharSequence, android.widget.Filter.FilterResults).

Contract: When the constraint is null, the original data must be restored.

Parameters
constraint CharSequence: the constraint used to filter the data
Returns
Filter.FilterResults the results of the filtering operation

See also:

publishResults

Added in API level 1
void publishResults (CharSequence constraint, 
                Filter.FilterResults results)

Invoked in the UI thread to publish the filtering results in the user interface. Subclasses must implement this method to display the results computed in performFiltering(CharSequence).

Parameters
constraint CharSequence: the constraint used to filter the data
results Filter.FilterResults: the results of the filtering operation

See also:

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