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Class Ext.util.Observable

Package:Ext.util
Class:Observable
Extends:Object
Subclasses:BasicDialog, BasicLayoutRegion, Button, Component, ContentPanel, LayoutManager, Resizable, SplitBar, TabPanel, TabPanelItem, UpdateManager, View, Node, Store, Tree, BasicForm, AbstractSelectionModel, ColumnModel, Grid, Menu, DefaultSelectionModel, MultiSelectionModel, 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.events = {
        "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.releaseCapture(Observable o) : void Observable
<static> Removes all added captures from the Observable.
  addEvents(Object object) : void Observable
Copies any events from the passed object onto this object if they do not already exist. The passed object must also ...
  addListener(String eventName, Function handler, [Object scope], [Object options]) : void Observable
Appends an event handler to this component
  fireEvent(String eventName, Object... args) : Boolean Observable
Fires the specified event with the passed parameters (minus the event name).
  hasListener(String eventName) : Boolean Observable
Checks to see if this object is currently listening for a specified event
  on(String eventName, Function handler, [Object options]) : void Observable
Appends an event handler to this element (shorthand for addListener)
  purgeListeners() : void Observable
Removes all listeners for this object
  removeListener(String eventName, Function handler, [Object scope]) : void Observable
Removes a listener
  un(String eventName, Function handler, [Object scope]) : void Observable
Removes a listener (shorthand for removeListener)

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)
Copies any events from the passed object onto this object if they do not already exist. The passed object must also inherit from Observable for this method to have any effect.
Parameters:
  • object : Object
    The object from which to copy events
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.
    • delegate {String} A simple selector to filter the target or look for a descendant of the target
    • stopEvent {Boolean} True to stop the event. That is stop propagation, and prevent the default action.
    • preventDefault {Boolean} True to prevent the default action
    • stopPropagation {Boolean} True to prevent event propagation
    • normalized {Boolean} False to pass a browser event to the handler function instead of an Ext.EventObject
    • 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)

    Code: 
    el.on('click', this.onClick, this, { single: true, delay: 100, stopEvent : true, forumId: 4 });

    The method also allows for a single argument to be passed which is a config object containing properties which specify multiple handlers.

    Attaching multiple handlers in 1 call
    Code: 

    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:
    Code: 

    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 is currently listening 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 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
  • 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.
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