BasemapLayerList

The BasemapLayerList widget provides a way to display a list of Basemap layers and switch on/off their visibility. Base layers and reference layers are divided into separate sections. When editing is enabled, layers can be reordered by dragging and dropping between the lists and the title can be edited.

BasemapLayerList is very similar to our LayerList widget. See below samples for code inspiration:
Sample - LayerList widget
Sample - LayerList widget with actions

For information about gaining full control of widget styles, see the Styling topic.

See also:

Example:

var basemapLayerList = new BasemapLayerList({
  view: view
});
// Adds the widget below other elements in the top left corner of the view
view.ui.add(basemapLayerList, {
  position: "top-left"
});

Constructors

new BasemapLayerList(properties)

Parameter:

properties Object

optional

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

Example:

// typical usage
var BasemapLayerList = new BasemapLayerList({
  view: view
});

Property Overview

Any properties can be set, retrieved or listened to. See the Working with Properties topic.

Show inherited properties

Hide inherited properties

Type	Summary	Class
Collection<ListItem>	A collection of ListItems representing the baseLayers. more details	more details	BasemapLayerList
ListItemCreatedHandler	Specifies a function that accesses each ListItem representing a base layer. more details	more details	BasemapLayerList
String	The current basemap's title. more details	more details	BasemapLayerList
String\|HTMLElement	The ID or node representing the DOM element containing the widget. more details	more details	Widget
String	The name of the class. more details	more details	Accessor
Boolean	Indicates whether the basemap’s title, layer order and layer grouping can be edited by the user. more details	more details	BasemapLayerList
String	The widget's default CSS icon class. more details	more details	iconClass
String	The unique ID assigned to the widget when the widget is created. more details	more details	Widget
String	The widget's default label. more details	more details	BasemapLayerList
Boolean	Indicates whether more than one list item may be selected by the user at a single time. more details	more details	BasemapLayerList
Collection<ListItem>	A collection of ListItems representing the referenceLayers. more details	more details	BasemapLayerList
ListItemCreatedHandler	Specifies a function that accesses each ListItem representing a reference layer. more details	more details	BasemapLayerList
Collection<ListItem>	A collection of selected ListItems representing basemap layers selected by the user. more details	more details	BasemapLayerList
Boolean	Option for enabling status indicators, which indicate whether or not each layer is loading resources. more details	more details	BasemapLayerList
MapView\|SceneView	A reference to the MapView or SceneView. more details	more details	BasemapLayerList
BasemapLayerListViewModel	The view model for this widget. more details	more details	BasemapLayerList
VisibleElements	The visible elements that are displayed within the widget. more details	more details	BasemapLayerList

Property Details

baseItems Collection<ListItem>readonly

A collection of ListItems representing the baseLayers.

baseListItemCreatedFunction ListItemCreatedHandler

Specifies a function that accesses each ListItem representing a base layer. Each list item's modifiable properties can be updated within. Actions can be added to list items using the actionsSections property of the ListItem.

Example:

var bmLayerList = new BasemapLayerList({
  view: view,
  editingEnabled: true,
  baseListItemCreatedFunction: function(event){
    baseListItem = event.item;
    if(baseListItem.title === "World Imagery_01"){
      // clean up title
      baseListItem.title = "World Imagery";
      // open the baseList item
      baseListItem.open = true;
    }
  }
})

basemapTitle String

The current basemap's title.

container String|HTMLElement inherited

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"
});

declaredClass Stringreadonly inherited

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

editingEnabled Boolean

Indicates whether the basemap’s title, layer order and layer grouping can be edited by the user. Any edits made will only be shown locally and will not be saved.

Default Value:false

Example:

// to enable editing
basemapLayerList.editingEnabled = true;

iconClass Stringinner

The widget's default CSS icon class.

id String inherited

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 String

The widget's default label.

multipleSelectionEnabled Boolean

Indicates whether more than one list item may be selected by the user at a single time. Selected items are available in the selectedItems property.

Default Value:false

See also:

selectedItems

Example:

basemapLayerList.multipleSelectionEnabled = true;

referenceItems Collection<ListItem>readonly

A collection of ListItems representing the referenceLayers.

referenceListItemCreatedFunction ListItemCreatedHandler

Specifies a function that accesses each ListItem representing a reference layer. Each list item's modifiable properties can be updated within. Actions can be added to list items using the actionsSections property of the ListItem.

Example:

var bmLayerList = new BasemapLayerList({
  view: view,
  editingEnabled: true,
  referenceListItemCreatedFunction: function(event){
    referenceListItem = event.item;
    if(referenceListItem.title === "World Imagery_01_reference_layer"){
      // clean up title
      referenceListItem.title = "Reference layer";
      // open the baseList item
      referenceListItem.open = true;
    }
  }
})

selectedItems Collection<ListItem>

A collection of selected ListItems representing basemap layers selected by the user.

statusIndicatorsVisible Boolean Deprecated since version 4.15. Use BasemapLayerList.visibleElements.statusIndicators instead.

Option for enabling status indicators, which indicate whether or not each layer is loading resources.

Default Value:true

Example:

// disable status indicators for all layers listed in BasemapLayerList
basemapLayerList.statusIndicatorsVisible = false;

view MapView|SceneView

A reference to the MapView or SceneView. Set this to link the widget to a specific view.

viewModel BasemapLayerListViewModel

The view model for this widget. This is a class that contains all the logic (properties and methods) that controls this widget's behavior. See the BasemapLayerListViewModel class to access all properties and methods on the widget.

visibleElements VisibleElementsautocast Since: ArcGIS API for JavaScript 4.15

The visible elements that are displayed within the widget. This property provides the ability to turn individual elements of the widget's display on/off.

Example:

basemapLayerList.visibleElements = {
  statusIndicators: false
};

Method Overview

Show inherited methods

Hide inherited methods

Return Type	Summary	Class
String	A utility method used for building the value for a widget's `class` property. more details	more details	Widget
	Destroys the widget instance. more details	more details	Widget
Boolean	Emits an event on the instance. more details	more details	Widget
Boolean	Indicates whether there is an event listener on the instance that matches the provided event name. more details	more details	Widget
Object	Registers an event handler on the instance. more details	more details	Widget
	Widget teardown helper. more details	more details	Widget
	This method is primarily used by developers when implementing custom widgets. more details	more details	Widget
Object	This method is primarily used by developers when implementing custom widgets. more details	more details	Widget
	Renders widget to the DOM immediately. more details	more details	Widget
	This method is primarily used by developers when implementing custom widgets. more details	more details	Widget
	Triggers the trigger-action event and executes the given action or action toggle. more details	more details	BasemapLayerList

Method Details

classes(classNames){String}inherited

A utility method used for building the value for a widget's class property. This aids in simplifying CSS class setup.

Parameter:

classNames String|String []|Object

repeatable

The class names.

Returns:

Type	Description
String	The computed class name.

See also:

Guide - Widget development (rendering)

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()inherited

Destroys the widget instance.

emit(type, event){Boolean}inherited

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}inherited

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}inherited

Registers an event handler on the instance. Call this method to hook an event with a listener.

Parameters:

type String|String []

A event type, or an array of event types, to listen for.

listener Function

The 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(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(handles)inherited

Widget teardown helper. Any handles added to it will be automatically removed when the widget is destroyed.

Parameter:

handles WatchHandle|WatchHandle []

Handles marked for removal once the widget is destroyed.

postInitialize()inherited

This method is primarily used by developers when implementing custom widgets. Executes after widget is ready for rendering.

render(){Object}inherited

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()inherited

Renders widget to the DOM immediately.

scheduleRender()inherited

This method is primarily used by developers when implementing custom widgets. Schedules widget rendering. This method is useful for changes affecting the UI.

triggerAction(action, item)

Triggers the trigger-action event and executes the given action or action toggle.

Parameters:

action ActionButton|ActionToggle

The action to execute.

item ListItem

An item associated with the action.

Type Definitions

ListItemCreatedHandler(event)

Function definition for the baseListItemCreatedFunction and referenceListItemCreatedFunction properties. See the example snippets in the documentations for those properties for more details.

Parameters:

event Object

An object containing a list item created by the LayerList.

Specification:

item ListItem

A list item created by the LayerList. You can modify the properties of this item to customize the text, actions, panel content, and visibility of the list item. See the documentation for the listItemCreatedFunction for more details.

VisibleElements

The visible elements that are displayed within the widget. This provides the ability to turn individual elements of the widget's display on/off.

Properties:

statusIndicators Boolean

optional

Indicates whether to the status indicators will be displayed. Default is true.

baseLayers Boolean

optional

Indicates whether to the base layers will be displayed. Default is true.

referenceLayers Boolean

optional

Indicates whether to the reference layers will be displayed. Default is true.

Event Overview

Name	Type	Summary	Class
	{action: ActionButton,ActionToggle,item: ListItem}	Fires after the user clicks on an action or action toggle inside the BasemapLayerList widget. more details	more details	BasemapLayerList

Event Details

trigger-action

Fires after the user clicks on an action or action toggle inside the BasemapLayerList widget. This event may be used to define a custom function to execute when particular actions are clicked.

Properties:

action ActionButton|ActionToggle

The action clicked by the user.

item ListItem

An item associated with the action.

ArcGIS API for JavaScript

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