The base class for widgets. Each widget's presentation is separate from its properties, methods, and data.
The separation of core logic and presentation makes each widget highly customizable when working with other frameworks and libraries such as Bootstrap, React, and JQuery.
The properties and methods of each widget are handled in its viewModel
property, which is an
Accessor-based class. Since each view model class extends Accessor,
all properties on the widget can be accessed using the methods outlined in the
Working with properties topic.
This design allows developers to create new widgets and repurpose existing widgets with a third party framework. Separation of a widget's presentation and core logic also means developers can use the logic without having to render its UI components. More information about creating custom widgets is available in the Widget development Guide topic.
Property Overview
Name | Type | Summary | Class | |
---|---|---|---|---|
String|HTMLElement | more details The ID or node representing the DOM element containing the widget. | more details | Widget | |
String | more details The name of the class. | more details | Accessor | |
String | more details The unique ID assigned to the widget when the widget is created. | more details | Widget | |
String | more details The widget's label. | more details | Widget | |
Boolean | more details Indicates whether the widget is visible. | more details | Widget |
Property Details
-
-
The ID or node representing the DOM element containing the widget. This property can only be set once. The following examples are all valid use cases when working with widgets.
Examples:// Create the HTML div element programmatically at runtime and set to the widget's container const basemapGallery = new BasemapGallery({ view: view, container: document.createElement("div") }); // Add the widget to the top-right corner of the view view.ui.add(basemapGallery, { position: "top-right" });
// Specify an already-defined HTML div element in the widget's container const basemapGallery = new BasemapGallery({ view: view, container: basemapGalleryDiv }); // Add the widget to the top-right corner of the view view.ui.add(basemapGallery, { position: "top-right" }); // HTML markup <body> <div id="viewDiv"></div> <div id="basemapGalleryDiv"></div> </body>
// Specify the widget while adding to the view's UI const basemapGallery = new BasemapGallery({ view: view }); // Add the widget to the top-right corner of the view view.ui.add(basemapGallery, { position: "top-right" });
-
Since: ArcGIS API for JavaScript 4.7
-
The name of the class. The declared class name is formatted as
esri.folder.className
.
-
id String
-
The unique ID assigned to the widget when the widget is created. If not set by the developer, it will default to the container ID, or if that is not present then it will be automatically generated.
-
label StringSince: ArcGIS API for JavaScript 4.11
-
The widget's label.
This property is useful whenever the widget is controlled by another one (e.g. Expand)
-
visible Boolean
-
Indicates whether the widget is visible.
If
false
, the widget will no longer be rendered in the web document. This may affect the layout of other elements or widgets in the document. For example, if this widget is the first of three widgets associated to the upper right hand corner of the view UI, then the other widgets will reposition when this widget is made invisible. For more information, refer to the CSS display value of"none"
.- Default Value:true
Example:// Hides the widget in the view widget.visible = false;
Method Overview
Name | Return Type | Summary | Class | |
---|---|---|---|---|
String | more details A utility method used for building the value for a widget's | more details | Widget | |
more details Destroys the widget instance. | more details | Widget | ||
Boolean | more details Emits an event on the instance. | more details | Widget | |
Boolean | more details Indicates whether there is an event listener on the instance that matches the provided event name. | more details | Widget | |
Boolean | more details
| more details | Widget | |
Boolean | more details
| more details | Widget | |
Boolean | more details
| more details | Widget | |
Object | more details Registers an event handler on the instance. | more details | Widget | |
more details Adds one or more handles which are to be tied to the lifecycle of the object. | more details | Accessor | ||
more details This method is primarily used by developers when implementing custom widgets. | more details | Widget | ||
Object | more details This method is primarily used by developers when implementing custom widgets. | more details | Widget | |
more details Renders widget to the DOM immediately. | more details | Widget | ||
more details This method is primarily used by developers when implementing custom widgets. | more details | Widget | ||
Promise | more details
| more details | Widget |
Method Details
-
classes(classNames){String}Since: ArcGIS API for JavaScript 4.7
-
A utility method used for building the value for a widget's
class
property. This aids in simplifying CSS class setup.Parameter:repeatable The class names.
Returns:Type Description String The computed class name. - See also:
Example:// .tsx syntax showing how to set CSS classes while rendering the widget render() { const dynamicIconClasses = { [CSS.myIcon]: this.showIcon, [CSS.greyIcon]: !this.showIcon }; return ( <div class={classes(CSS.root, CSS.mixin, dynamicIconClasses)} /> ); }
-
destroy()
-
Destroys the widget instance.
-
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 StringThe name of the event.
event ObjectoptionalThe 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 StringThe name of the event.
Returns:Type Description Boolean Returns true if the class supports the input event.
-
isFulfilled(){Boolean}Since: ArcGIS API for JavaScript 4.19
-
isFulfilled()
may be used to verify if creating an instance of the class is fulfilled (either resolved or rejected). If it is fulfilled,true
will be returned.Returns:Type Description Boolean Indicates whether creating an instance of the class has been fulfilled (either resolved or rejected).
-
isRejected(){Boolean}Since: ArcGIS API for JavaScript 4.19
-
isRejected()
may be used to verify if creating an instance of the class is rejected. If it is rejected,true
will be returned.Returns:Type Description Boolean Indicates whether creating an instance of the class has been rejected.
-
isResolved(){Boolean}Since: ArcGIS API for JavaScript 4.19
-
isResolved()
may be used to verify if creating an instance of the class is resolved. If it is resolved,true
will be returned.Returns:Type Description Boolean Indicates whether creating an instance of the class has been resolved.
-
on(type, listener){Object}
-
Registers an event handler on the instance. Call this method to hook an event with a listener.
Parameters:An event or an array of events to listen for.
listener FunctionThe 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); });
-
own(handleOrHandles)inheritedSince: ArcGIS API for JavaScript 4.24
-
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.whenOnce(() => !view.updating) .then(() => { wkidSelect.disabled = false; }); handle.remove(); // Assign a handle using own() this.own(reactiveUtils.whenOnce(() => !view.updating) .then(() => { wkidSelect.disabled = false; }));
Parameter:handleOrHandles WatchHandle|WatchHandle[]Handles marked for removal once the object is destroyed.
-
postInitialize()
-
This method is primarily used by developers when implementing custom widgets. Executes after widget is ready for rendering.
-
render(){Object}
-
This method is primarily used by developers when implementing custom widgets. It must be implemented by subclasses for rendering.
Returns:Type Description Object The rendered virtual node.
-
renderNow()
-
Renders widget to the DOM immediately.
-
scheduleRender()
-
This method is primarily used by developers when implementing custom widgets. Schedules widget rendering. This method is useful for changes affecting the UI.
-
when(callback, errback){Promise}Since: ArcGIS API for JavaScript 4.19
-
when()
may be leveraged once an instance of the class is created. This method takes two input parameters: acallback
function and anerrback
function. Thecallback
executes when the instance of the class loads. Theerrback
executes if the instance of the class fails to load.Parameters:callback FunctionoptionalThe function to call when the promise resolves.
errback FunctionoptionalThe function to execute when the promise fails.
Returns:Type Description Promise Returns a new promise for the result of callback
that may be used to chain additional functions.Example:// Although this example uses the BasemapGallery widget, any class instance that is a promise may use when() in the same way let bmGallery = new BasemapGallery(); bmGallery.when(function(){ // This function will execute once the promise is resolved }, function(error){ // This function will execute if the promise is rejected due to an error });