Class: Observable

ol.Observable

Abstract base class; normally only used for creating subclasses and not instantiated in apps. An event target providing convenient methods for listener registration and unregistration. A generic change event is always available through ol.Observable#changed.

new ol.Observable()

Fires:
  • change experimental - Triggered when the revision counter is increased.

Subclasses

Extends

  • goog.events.EventTarget

Methods

ol.Observable.unByKey(key)

Removes an event listener using the key returned by on() or once().

Name Type Description
key goog.events.Key

The key returned by on() or once().

changed() experimental

Increases the revision counter and dispatches a 'change' event.

getRevision(){number} experimental

Get the version number for this object. Each time the object is modified, its version number will be incremented.

Returns:
Revision.

on(type, listener, opt_this){goog.events.Key}

Listen for a certain type of event.

Name Type Description
type string | Array.<string>

The event type or array of event types.

listener function

The listener function.

this Object

The object to use as this in listener.

Returns:
Unique key for the listener.

once(type, listener, opt_this){goog.events.Key}

Listen once for a certain type of event.

Name Type Description
type string | Array.<string>

The event type or array of event types.

listener function

The listener function.

this Object

The object to use as this in listener.

Returns:
Unique key for the listener.

un(type, listener, opt_this)

Unlisten for a certain type of event.

Name Type Description
type string | Array.<string>

The event type or array of event types.

listener function

The listener function.

this Object

The object which was used as this by the listener.

Removes an event listener using the key returned by on() or once(). Note that using the ol.Observable.unByKey static function is to be preferred.

Name Type Description
key goog.events.Key

The key returned by on() or once().