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 | |
|---|---|---|---|
| String | HTMLElement | The ID or node representing the DOM element containing the widget. more details | more details | |
| String | The name of the class. more details | more details | |
| Boolean | When | more details | |
| String | The unique ID assigned to the widget when the widget is created. more details | more details | |
Property Details
containerString|HTMLElement
The ID or node representing the DOM element containing the widget. This property can only be set once.
declaredClassStringreadonly
The name of the class. The declared class name is formatted as
esri.folder.className.destroyedBoolean
When
true, this property indicates whether the widget has been destroyed.idString
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.
Method Overview
| Name | Return Type | Summary | |
|---|---|---|---|
Destroys the widget instance. more details | more details | ||
| Boolean | Indicates whether there is an event listener on the instance that matches the provided event name. more details | more details | |
| Object | Registers an event handler on the instance. more details | more details | |
Widget teardown helper. more details | more details | ||
This method is primarily used by developers when implementing custom widgets. more details | more details | ||
| Object | This method is primarily used by developers when implementing custom widgets. more details | more details | |
Renders widget to the DOM immediately. more details | more details | ||
This method is primarily used by developers when implementing custom widgets. more details | more details | ||
Finalizes the creation of the widget. more details | more details | ||
Method Details
destroy()
Destroys the widget instance.
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. 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 listened events.
Parameters:type StringThe name of event to listen for.
listener FunctionThe function to call when the event is fired.
Returns:Type Description Object Returns an event handler with a remove()method that can be called to stop listening for the event.Property Type Description remove Function When called, removes the listener from the event. - See also:
Example:view.on("click", function(event){ // event is the event handle returned after the event fires. console.log(event.mapPoint); });own(handles)
Widget teardown helper. Any handles added to it will be automatically removed when the widget is destroyed.
Parameter:handles Handle[]@type - handles to remove when 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.
- Deprecated
startup()
- since version 4.2.
Finalizes the creation of the widget.