OpenLayers 3

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()

src/ol/observable.js, line 22
Fires:
  • change experimental - Triggered when the revision counter is increased.

Subclasses

Extends

Methods

ol.Observable.unByKey(key)

src/ol/observable.js, line 42

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

Name Type Description
key ol.events.Key | Array.<ol.events.Key>

The key returned by on() or once() (or an array of keys).

changed() experimental

src/ol/observable.js, line 57

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

dispatchEvent(event) experimental

src/ol/observable.js, line 81

Dispatches an event and calls all listeners listening for events of this type. The event parameter can either be a string or an Object with a type property.

Name Type Description
event Object | ol.events.Event | string

Event object.

getRevision(){number} experimental

src/ol/observable.js, line 90

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){ol.events.Key|Array.<ol.events.Key>}

src/ol/observable.js, line 105

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. If called with an array of event types as the first argument, the return will be an array of keys.

once(type, listener, opt_this){ol.events.Key|Array.<ol.events.Key>}

src/ol/observable.js, line 130

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. If called with an array of event types as the first argument, the return will be an array of keys.

un(type, listener, opt_this)

src/ol/observable.js, line 153

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.

unByKey(key)

src/ol/observable.js, line 174

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 ol.events.Key | Array.<ol.events.Key>

The key returned by on() or once() (or an array of keys).