Wikitude SDK API Reference

API Docs for: 4.0.2
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Tracker Class

Extends ARchitectObject
Module: AR

A Tracker represents a Target Collection which is created with the Target Management Tool.

A Tracker needs to include the binary .wtc targets describing the targets and needs to be referenced via a URI. The Tracker object is used to reference specific Trackable2DObjects (the targets inside the target collection).

Trackers can be enabled and disabled. Only one Tracker can be active at a time. The current enabled/disabled state of a Tracker is reflected in the enabled property. Should there be multiple Trackers used in the ARchitect file, the following logic applies to specify the currently active Tracker:

  • When a new Tracker is created, it is automatically set to the active one, unless it was created with enabled set to false.

  • When a specific Tracker is enabled, it is automatically set to the active one. The previously active Tracker is disabled by the system.
In case a Tracker is disabled by the system, the developer will be notified via the onDisabled trigger.

Example:
// a Tracker referencing a target collection on a server
var tracker1 = new AR.Tracker("http://myserver.com/targetCollection1.wtc" , {
  onDisabled : function(){
    //tracker has been disabled by the system
  }
});
var enabled = tracker1.enabled; //true

// a second tracker, which will cause tracker1 to be disabled
var tracker2 = new AR.Tracker("http://myserver.com/targetCollection1.wtc");

enabled = tracker1.enabled; //false
enabled = tracker2.enabled; //true

Constructor

Tracker

(
  • src
  • options
)

Parameters:

  • src String

    The URI to the target collection

  • options Object optional

    Setup-Parameters to customize additional object properties.

    Accepted options-properties are

Item Index

Methods

Properties

Events

Methods

destroy

()

Inherited from ARchitectObject

Destroys the object.

isLoaded

() Boolean

Returns a boolean value indicating if the tracker has already been successfully loaded.

Returns:

Boolean:

true if the Tracker has successfully loaded, false if the Tracker has not been successfully loaded yet.

Properties

destroyed

Boolean

Inherited from ARchitectObject

Indicates if the object has already been destroyed.

enabled

Boolean

The current activity state of the Tracker. This property might by changed automatically by the system, in case another Tracker is enabled, causing this Tracker to be disabled. The onDisabled trigger will be called in this case.

src

String

The URI pointing to the referenced target collection. The property is read-only and can only be set on creation.

Events

onDisabled

The trigger fires when the Tracker has been disabled by the system. It does not fire when enabled is set to false manually.

The trigger is null by default, and will thus result in no action executed when the trigger fires. A developer can add custom functionality by assigning a custom function to onDisabled.

onError

The trigger fires when the Tracker's target collection could not be loaded. Causes for this might include bad network connection or a corrupt target collection.

The trigger is null by default, and will thus result in no action executed when the trigger fires. A developer can add custom functionality by assigning a custom function to onError.

onLoaded

The trigger fires when the Tracker's target collection was successfully loaded. TrackableObjects related to this Tracker can only be tracked after the Tracker was successfully loaded.

The trigger is null by default, and will thus result in no action executed when the trigger fires. A developer can add custom functionality by assigning a custom function to onLoaded.