CallbackRegistry

public class CallbackRegistry
extends Object implements Cloneable

java.lang.Object
   ↳ android.databinding.CallbackRegistry<C, T, A>
Known Direct Subclasses

A utility for storing and notifying callbacks. This class supports reentrant modification of the callbacks during notification without adversely disrupting notifications. A common pattern for callbacks is to receive a notification and then remove themselves. This class handles this behavior with constant memory under most circumstances.

A subclass of CallbackRegistry.NotifierCallback must be passed to the constructor to define how notifications should be called. That implementation does the actual notification on the listener. It is typically a static instance that can be reused for all similar CallbackRegistries.

This class supports only callbacks with at most three parameters. Typically, these are the notification originator and a parameter, with another to indicate which method to call, but these may be used as required. If more than three parameters are required or primitive types other than the single int provided must be used, A should be some kind of containing structure that the subclass may reuse between notifications.

Summary

Nested classes

class CallbackRegistry.NotifierCallback<C, T, A>

Class used to notify events from CallbackRegistry. 

Public constructors

CallbackRegistry(NotifierCallback<C, T, A> notifier)

Creates an EventRegistry that notifies the event with notifier.

Public methods

void add(C callback)

Add a callback to be notified.

void clear()

Removes all callbacks from the list.

CallbackRegistry<C, T, A> clone()
ArrayList<C> copyCallbacks()

Makes a copy of the registered callbacks and returns it.

void copyCallbacks(List<C> callbacks)

Modifies callbacks to contain all callbacks in the CallbackRegistry.

boolean isEmpty()

Returns true if there are no registered callbacks or false otherwise.

void notifyCallbacks(T sender, int arg, A arg2)

Notify all callbacks.

void remove(C callback)

Remove a callback.

Inherited methods

From class java.lang.Object

Public constructors

CallbackRegistry

CallbackRegistry (NotifierCallback<C, T, A> notifier)

Creates an EventRegistry that notifies the event with notifier.

Parameters
notifier NotifierCallback: The class to use to notify events.

Public methods

add

void add (C callback)

Add a callback to be notified. If the callback is already in the list, another won't be added. This does not affect current notifications.

Parameters
callback C: The callback to add.

clear

void clear ()

Removes all callbacks from the list.

clone

CallbackRegistry<C, T, A> clone ()

Returns
CallbackRegistry<C, T, A> A copy of the CallbackRegistry with all callbacks listening to both instances.

copyCallbacks

ArrayList<C> copyCallbacks ()

Makes a copy of the registered callbacks and returns it.

Returns
ArrayList<C> a copy of the registered callbacks.

copyCallbacks

void copyCallbacks (List<C> callbacks)

Modifies callbacks to contain all callbacks in the CallbackRegistry.

Parameters
callbacks List: modified to contain all callbacks registered to receive events.

isEmpty

boolean isEmpty ()

Returns true if there are no registered callbacks or false otherwise.

Returns
boolean true if there are no registered callbacks or false otherwise.

notifyCallbacks

void notifyCallbacks (T sender, 
                int arg, 
                A arg2)

Notify all callbacks.

Parameters
sender T: The originator. This is an opaque parameter passed to onNotifyCallback(Object, Object, int, Object)
arg int: An opaque parameter passed to onNotifyCallback(Object, Object, int, Object)
arg2 A: An opaque parameter passed to onNotifyCallback(Object, Object, int, Object)

remove

void remove (C callback)

Remove a callback. This callback won't be notified after this call completes.

Parameters
callback C: The callback to remove.