require(["esri/widgets/Track/TrackViewModel"], (TrackVM) => { /* code goes here */ });
import TrackVM from "@arcgis/core/widgets/Track/TrackViewModel.js";
esri/widgets/Track/TrackViewModel
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 Track widget is only available in secure contexts, such as HTTPS. Note that localhost is considered "potentially secure" and can be used for easy testing in browsers that support Window.isSecureContext.
For additional information regarding this, visit the ArcGIS blog, Increased web API security in Google Chrome.
let trackWidget = new Track({
viewModel: { // autocasts as new TrackViewModel()
view: view, // attaches the Track to the view
}
};
Constructors
-
Parameterproperties Objectoptional
See the properties for a list of all the properties that may be passed into the constructor.
Property Overview
Name | Type | Summary | Class |
---|---|---|---|
The name of the class. | Accessor | ||
GeolocationPositionError|Error | Error that caused the last track-error event to fire. | TrackViewModel | |
An object used for setting optional position parameters. | TrackViewModel | ||
Indicates whether to navigate the view to the position and scale of the geolocated result. | TrackViewModel | ||
This function provides the ability to override either the MapView goTo() or SceneView goTo() methods. | TrackViewModel | ||
The graphic used to show the user's location on the map. | TrackViewModel | ||
A function that is used as an expression to evaluate geolocation points, and returns a boolean value. | TrackViewModel | ||
Indicates the scale to set on the view when navigating to the position of the geolocated result, after a location is returned from the track event. | TrackViewModel | ||
The current state of the widget. | TrackViewModel | ||
Indicates whether new positions are being watched. | TrackViewModel | ||
The view associated with the widget. | TrackViewModel |
Property Details
-
error
error GeolocationPositionError |Error
Since: ArcGIS Maps SDK for JavaScript 4.29TrackViewModel since 4.0, error added at 4.29. -
Error that caused the last track-error event to fire.
- Default Value:null
Exampleif(track.viewModel.state === 'error') console.error(track.viewModel.error);
-
geolocationOptions
geolocationOptions Object
-
An object used for setting optional position parameters. Refer to the Geolocation API Specification for details on using these parameters.
- Default Value:null
Exampleconst track = new Track({ view: view, // Set optional position parameters geolocationOptions: { maximumAge: 0, timeout: 15000, enableHighAccuracy: true } });
-
goToLocationEnabled
goToLocationEnabled Boolean
-
Indicates whether to navigate the view to the position and scale of the geolocated result.
- Default Value:true
-
goToOverride
goToOverride GoToOverride
Since: ArcGIS Maps SDK for JavaScript 4.8TrackViewModel since 4.0, goToOverride added at 4.8. -
This function provides the ability to override either the MapView goTo() or SceneView goTo() methods.
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 Graphic
-
The graphic used to show the user's location on the map.
Exampleconst trackWidget = new Track({ // Assign the track widget to a view view: view, // Overwrite the default symbol used for the // graphic placed at the location of the user graphic: new Graphic ({ symbol: { // autocasts as new SimpleMarkerSymbol() type: "simple-marker", size: "12px", color: "blue", // autocasts as new SimpleLineSymbol() outline: { color: "#efefef", width: "1.5px" } } }) });
-
positionFilterFunction
positionFilterFunction Function
Since: ArcGIS Maps SDK for JavaScript 4.27TrackViewModel since 4.0, positionFilterFunction added at 4.27. -
A function that is used as an expression to evaluate geolocation points, and returns a boolean value. If the function returns
true
, the widget will draw a graphic and navigate to the position. The widget will ignorefalse
values and not draw a graphic and not navigate to the position.Example use cases include smoothing out geolocation anomalies and geofencing.
- Default Value:null
Example// Exclude locations that full outside an extent. track.viewModel.positionFilterFunction = (value) => { const { longitude, latitude } = value.position.coords; const myLocation = new Point({ longitude, latitude }); const geofenceExtent = new Extent({ // whatever }); return geometryEngine.within(myLocation, geofenceExtent); };
-
scale
scale Number
Since: ArcGIS Maps SDK for JavaScript 4.7TrackViewModel since 4.0, scale added at 4.7. -
Indicates the scale to set on the view when navigating to the position of the geolocated result, after a location is returned from the track event.
By default, the view will navigate to a scale of
2500
for 3D and4514
for 2D. To override the default in 2D, set thescale
property and also set snapToZoom tofalse
. For 2D views the value should be within the effectiveMinScale and effectiveMaxScale.- Default Value:null
-
state
state Stringreadonly
-
The current state of the widget.
Possible Values:"disabled" |"ready" |"tracking" |"waiting" |"error"
- Default Value:disabled
-
tracking
tracking Booleanreadonly
-
Indicates whether new positions are being watched.
- Default Value:false
Method Overview
Name | Return Type | Summary | Class |
---|---|---|---|
Adds one or more handles which are to be tied to the lifecycle of the object. | Accessor | ||
Emits an event on the instance. | TrackViewModel | ||
Indicates whether there is an event listener on the instance that matches the provided event name. | TrackViewModel | ||
Returns true if a named group of handles exist. | Accessor | ||
Registers an event handler on the instance. | TrackViewModel | ||
Removes a group of handles owned by the object. | Accessor | ||
When executed, tracking starts at the user's location. | TrackViewModel | ||
Stops tracking the user's location when executed. | TrackViewModel |
Method Details
-
Inherited from Accessor
Since: ArcGIS Maps SDK for JavaScript 4.25Accessor since 4.0, addHandles added at 4.25. -
Adds one or more handles which are to be tied to the lifecycle of the object. The handles will be removed when the object is destroyed.
// Manually manage handles const handle = reactiveUtils.when( () => !view.updating, () => { wkidSelect.disabled = false; }, { once: true } ); this.addHandles(handle); // Destroy the object this.destroy();
ParametershandleOrHandles WatchHandle|WatchHandle[]Handles marked for removal once the object is destroyed.
groupKey *optionalKey identifying the group to which the handles should be added. All the handles in the group can later be removed with Accessor.removeHandles(). If no key is provided the handles are added to a default group.
-
hasHandles
InheritedMethodhasHandles(groupKey){Boolean}
Inherited from AccessorSince: ArcGIS Maps SDK for JavaScript 4.25Accessor since 4.0, hasHandles added at 4.25. -
Returns true if a named group of handles exist.
ParametergroupKey *optionalA group key.
ReturnsType Description Boolean Returns true
if a named group of handles exist.Example// Remove a named group of handles if they exist. if (obj.hasHandles("watch-view-updates")) { obj.removeHandles("watch-view-updates"); }
-
on
on(type, listener){Object}
-
Registers an event handler on the instance. Call this method to hook an event with a listener.
ParametersReturnsType 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. Exampleview.on("click", function(event){ // event is the event handle returned after the event fires. console.log(event.mapPoint); });
-
Inherited from Accessor
Since: ArcGIS Maps SDK for JavaScript 4.25Accessor since 4.0, removeHandles added at 4.25. -
Removes a group of handles owned by the object.
ParametergroupKey *optionalA group key or an array or collection of group keys to remove.
Exampleobj.removeHandles(); // removes handles from default group obj.removeHandles("handle-group"); obj.removeHandles("other-handle-group");
-
When executed, tracking starts at the user's location.
Event Overview
Name | Type | Summary | Class |
---|---|---|---|
|
{position: Object} |
Fires after the start() method is called and a position is found. |
TrackViewModel |
|
{error: GeolocationPositionError|Error} |
Fires after the start() method is called and an error is returned. |
TrackViewModel |
Event Details
-
Fires after the start() method is called and a position is found.
- Property
-
position Object
Position returned from the Geolocation API.