Class Ext.util.Observable

Package:	Ext.util
Class:	Observable
Extends:	Object
Subclasses:	BasicDialog, BasicLayoutRegion, Button, Component, ContentPanel, LayoutManager, Resizable, SplitBar, TabPanel, TabPanelItem, UpdateManager, View, Connection, Node, Store, Tree, BasicForm, AbstractSelectionModel, ColumnModel, Grid, GridView, Menu, DefaultSelectionModel, MultiSelectionModel, TreeLoader, ClickRepeater, MixedCollection
Defined In:	Observable.js

Abstract base class that provides a common interface for publishing events. Subclasses are expected to to have a property "events" with all the events defined.
For example:

Employee = function(name){
    this.name = name;
    this.addEvents({
        "fired" : true,
        "quit" : true
    });
 }
 Ext.extend(Employee, Ext.util.Observable);

Properties - Methods - Events

Public Properties

This class has no public properties.

Public Methods

Method		Defined By
	Observable.capture( `Observable o`, `Function fn`, [`Object scope`] ) : void	Observable
	<static> Starts capture on the specified Observable. All events will be passed to the supplied function with th...	Observable
	Observable.releaseCapture( `Observable o` ) : void	Observable
	<static> Removes all added captures from the Observable.	Observable
	addEvents( `Object object` ) : void	Observable
	Used to define events on this Observable	Observable
	addListener( `String eventName`, `Function handler`, [`Object scope`], [`Object options`] ) : void	Observable
	Appends an event handler to this component	Observable
	fireEvent( `String eventName`, `Object... args` ) : Boolean	Observable
	Fires the specified event with the passed parameters (minus the event name).	Observable
	hasListener( `String eventName` ) : Boolean	Observable
	Checks to see if this object has any listeners for a specified event	Observable
	on( `String eventName`, `Function handler`, [`Object scope`], [`Object options`] ) : void	Observable
	Appends an event handler to this element (shorthand for addListener)	Observable
	purgeListeners() : void	Observable
	Removes all listeners for this object	Observable
	removeListener( `String eventName`, `Function handler`, [`Object scope`] ) : void	Observable
	Removes a listener	Observable
	un( `String eventName`, `Function handler`, [`Object scope`] ) : void	Observable
	Removes a listener (shorthand for removeListener)	Observable

Public Events

This class has no public events.

Method Details

Observable.capture

public function Observable.capture( Observable o, Function fn, [Object scope] )

<static> Starts capture on the specified Observable. All events will be passed to the supplied function with the event name + standard signature of the event before the event is fired. If the supplied function returns false, the event will not fire.

Parameters:

o : Observable
The Observable to capture
fn : Function
The function to call
scope : Object
(optional) The scope (this object) for the fn

Returns:

void

This method is defined by Observable.

Observable.releaseCapture

public function Observable.releaseCapture( Observable o )

<static> Removes all added captures from the Observable.

Parameters:

o : Observable
The Observable to release

Returns:

void

This method is defined by Observable.

addEvents

public function addEvents( Object object )

Used to define events on this Observable

Parameters:

object : Object
The object with the events defined

Returns:

void

This method is defined by Observable.

addListener

public function addListener( String eventName, Function handler, [Object scope], [Object options] )

Appends an event handler to this component

Parameters:

eventName : String
The type of event to listen for
handler : Function
The method the event invokes
scope : Object
(optional) The scope in which to execute the handler function. The handler function's "this" context.
options : Object
(optional) An object containing handler configuration properties. This may contain any of the following properties:
- scope {Object} The scope in which to execute the handler function. The handler function's "this" context.
- delay {Number} The number of milliseconds to delay the invocation of the handler after te event fires.
- single {Boolean} True to add a handler to handle just the next firing of the event, and then remove itself.
- buffer {Number} Causes the handler to be scheduled to run in an Ext.util.DelayedTask delayed by the specified number of milliseconds. If the event fires again within that time, the original handler is not invoked, but the new handler is scheduled in its place.
Combining Options
Using the options argument, it is possible to combine different types of listeners:

A normalized, delayed, one-time listener that auto stops the event and passes a custom argument (forumId)
```
el.on('click', this.onClick, this, {
 			single: true,
    		delay: 100,
    		forumId: 4
		});
```
Attaching multiple handlers in 1 call
The method also allows for a single argument to be passed which is a config object containing properties which specify multiple handlers.
```
el.on({
			'click': {
        		fn: this.onClick,
        		scope: this,
        		delay: 100
    		}, 
    		'mouseover': {
        		fn: this.onMouseOver,
        		scope: this
    		},
    		'mouseout': {
        		fn: this.onMouseOut,
        		scope: this
    		}
		});
```
Or a shorthand syntax which passes the same scope object to all handlers:
```
el.on({
			'click': this.onClick,
    		'mouseover': this.onMouseOver,
    		'mouseout': this.onMouseOut,
    		scope: this
		});
```

Returns:

void

This method is defined by Observable.

fireEvent

public function fireEvent( String eventName, Object... args )

Fires the specified event with the passed parameters (minus the event name).

Parameters:

eventName : String
args : Object...
Variable number of parameters are passed to handlers

Returns:

Boolean
returns false if any of the handlers return false otherwise it returns true

This method is defined by Observable.

hasListener

public function hasListener( String eventName )

Checks to see if this object has any listeners for a specified event

Parameters:

eventName : String
The name of the event to check for

Returns:

Boolean
True if the event is being listened for, else false

This method is defined by Observable.

on

public function on( String eventName, Function handler, [Object scope], [Object options] )

Appends an event handler to this element (shorthand for addListener)

Parameters:

eventName : String
The type of event to listen for
handler : Function
The method the event invokes
scope : Object
(optional) The scope in which to execute the handler function. The handler function's "this" context.
options : Object
(optional)

Returns:

void

This method is defined by Observable.

purgeListeners

public function purgeListeners()

Removes all listeners for this object

Parameters:

None.

Returns:

void

This method is defined by Observable.

removeListener

public function removeListener( String eventName, Function handler, [Object scope] )

Removes a listener

Parameters:

eventName : String
The type of event to listen for
handler : Function
The handler to remove
scope : Object
(optional) The scope (this object) for the handler

Returns:

void

This method is defined by Observable.

un

public function un( String eventName, Function handler, [Object scope] )

Removes a listener (shorthand for removeListener)

Parameters:

eventName : String
The type of event to listen for
handler : Function
The handler to remove
scope : Object
(optional) The scope (this object) for the handler

Returns:

void

This method is defined by Observable.