TrackViewModel

AMD: require(["esri/widgets/Track/TrackViewModel"], (TrackVM) => { /* code goes here */ });
ESM: import TrackVM from "@arcgis/core/widgets/Track/TrackViewModel";
Class: esri/widgets/Track/TrackViewModel
Inheritance: TrackViewModel Accessor
Since: ArcGIS API for JavaScript 4.0

Provides the logic for the Track widget, which animates the View to the user's location when clicked and tracks it as the location is updated.

The (geolocation) functionality is not supported on insecure origins. To use it, switch your application to a secure origin, such as HTTPS. Note that localhost is considered "potentially secure" and can be used for easy testing in browsers that supports Window.isSecureContext (currently Chrome and Firefox).

As of version 4.2, the Track Button no longer displays in non-secure web apps. At version 4.1 this only applied to Google Chrome.

See also:
Example:
let trackWidget = new Track({
  viewModel: {  // autocasts as new TrackViewModel()
    view: view,   // attaches the Track to the view
  }
}, "trackDiv");

Constructors

new TrackViewModel(properties)
Parameter:
properties Object
optional

See the properties for a list of all the properties that may be passed into the constructor.

Property Overview

Any properties can be set, retrieved or listened to. See the Working with Properties topic.
Show inherited properties Hide inherited properties
Name Type Summary Class
Stringmore details

The name of the class.

more detailsAccessor
Objectmore details

The HTML5 Geolocation Position options for locating.

more detailsTrackViewModel
Booleanmore details

Indicates whether to navigate the view to the position and scale of the geolocated result.

more detailsTrackViewModel
GoToOverridemore details

This function provides the ability to override either the MapView goTo() or SceneView goTo() methods.

more detailsTrackViewModel
Graphicmore details

The graphic used to show the user's location on the map.

more detailsTrackViewModel
Numbermore details

The scale to set on the view when navigating to the position of the geolocated result.

more detailsTrackViewModel
Stringmore details

The current state of the widget.

more detailsTrackViewModel
Booleanmore details

Indicates whether new positions are being watched.

more detailsTrackViewModel
MapView|SceneViewmore details

The view associated with the widget.

more detailsTrackViewModel

Property Details

declaredClass Stringreadonly inherited
Since: ArcGIS API for JavaScript 4.7

The name of the class. The declared class name is formatted as esri.folder.className.

geolocationOptions Object

The HTML5 Geolocation Position options for locating. Refer to Geolocation API Specification for details.

Default Value:{ maximumAge: 0, timeout: 15000, enableHighAccuracy: true }
goToLocationEnabled Boolean

Indicates whether to navigate the view to the position and scale of the geolocated result.

Default Value:true
goToOverride GoToOverride
Since: ArcGIS API for JavaScript 4.8

This function provides the ability to override either the MapView goTo() or SceneView goTo() methods.

See also:
Example:
// The following snippet uses the Search widget but can be applied to any
// widgets that support the goToOverride property.
search.goToOverride = function(view, goToParams) {
  goToParams.options.duration = updatedDuration;
  return view.goTo(goToParams.target, goToParams.options);
};
graphic Graphic

The graphic used to show the user's location on the map.

Example:
let locateWidget = new Locate({
  viewModel: { // autocasts as new LocateViewModel()
    view: view,  // Assigns the locate widget to a view
    graphic: new Graphic({
      symbol: { type: "simple-marker" }  // Overwrites the default symbol used for the
      // graphic placed at the location of the user when found
    })
  }
});
scale Number
Since: ArcGIS API for JavaScript 4.7

The scale to set on the view when navigating to the position of the geolocated result. If a scale value is not explicitly set, then the view will navigate to a default scale of 2500.

Default Value:null
state Stringreadonly

The current state of the widget.

Possible Values:"disabled"|"ready"|"tracking"|"waiting"

Default Value:disabled
tracking Booleanreadonly

Indicates whether new positions are being watched.

Default Value:false

The view associated with the widget.

Method Overview

Name Return Type Summary Class
Booleanmore details

Emits an event on the instance.

more detailsTrackViewModel
Booleanmore details

Indicates whether there is an event listener on the instance that matches the provided event name.

more detailsTrackViewModel
Objectmore details

Registers an event handler on the instance.

more detailsTrackViewModel
more details

When executed, tracking starts at the user's location.

more detailsTrackViewModel
more details

Stops tracking the user's location when executed.

more detailsTrackViewModel

Method Details

emit(type, event){Boolean}
Since: ArcGIS API for JavaScript 4.5

Emits an event on the instance. This method should only be used when creating subclasses of this class.

Parameters:
type String

The name of the event.

event Object
optional

The event payload.

Returns:
Type Description
Boolean true if a listener was notified
hasEventListener(type){Boolean}

Indicates whether there is an event listener on the instance that matches the provided event name.

Parameter:
type String

The name of the event.

Returns:
Type Description
Boolean Returns true if the class supports the input event.
on(type, listener){Object}

Registers an event handler on the instance. Call this method to hook an event with a listener. See the Events summary table for a list of supported events.

Parameters:

An event or an array of events to listen for.

listener Function

The function to call when the event fires.

Returns:
Type Description
Object Returns an event handler with a remove() method that should be called to stop listening for the event(s).
Property Type Description
remove Function When called, removes the listener from the event.
Example:
view.on("click", function(event){
  // event is the event handle returned after the event fires.
  console.log(event.mapPoint);
});
start()

When executed, tracking starts at the user's location.

stop()

Stops tracking the user's location when executed.

Event Overview

Name Type Summary Class
{position: Object}
more details

Fires after the start() method is called and a position is found.

more details TrackViewModel
{error: Error}
more details

Fires after the start() method is called and an error is returned.

more details TrackViewModel

Event Details

track

Fires after the start() method is called and a position is found.

Property:
position Object

Geoposition returned from the Geolocation API.

track-error

Fires after the start() method is called and an error is returned.

Property:
error Error

The Error object returned if an error occurred while tracking.

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