LayerList

require(["esri/widgets/LayerList"], function(LayerList) { /* code goes here */ });

Class: esri/widgets/LayerList

Inheritance: LayerList Widget Accessor

Since: ArcGIS API for JavaScript 4.2

The LayerList widget provides a way to display a list of layers, and switch on/off their visibility. The ListItem API provides access to each layer's properties, allows the developer to configure actions related to the layer, and allows the developer to add content to the item related to the layer.

To hide layers in the map from the LayerList widget, you must set the listMode property on the desired layers to hide.

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

See also:

Example:

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

Constructors

new LayerList(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 layerlist = new LayerList({
  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
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	When `true`, this property indicates whether the widget has been destroyed. more details	more details	Widget
String	The widget's default CSS icon class. more details	more details	LayerList
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	LayerList
ListItemCreatedHandler	Specifies a function that accesses each ListItem. more details	more details	LayerList
Boolean	Indicates whether more than one list item may be selected by the user at a single time. more details	more details	LayerList
Collection<ListItem>	A collection of ListItems representing operational layers. more details	more details	LayerList
Collection<ListItem>	A collection of selected ListItems representing operational layers selected by the user. more details	more details	LayerList
Boolean	Indicates whether list items may be selected by the user. more details	more details	LayerList
Boolean	Option for enabling status indicators, which indicate whether or not each layer is loading resources. more details	more details	LayerList
MapView\|SceneView	A reference to the MapView or SceneView. more details	more details	LayerList
LayerListViewModel	The view model for this widget. more details	more details	LayerList

Property Details

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 Since: ArcGIS API for JavaScript 4.7

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

destroyed Boolean inherited

When true, this property indicates whether the widget has been destroyed.

iconClass String Since: ArcGIS API for JavaScript 4.7

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 Since: ArcGIS API for JavaScript 4.7

The widget's default label.

listItemCreatedFunction ListItemCreatedHandler Since: ArcGIS API for JavaScript 4.4

Specifies a function that accesses each ListItem. Each list item can be modified according to its modifiable properties. Actions can be added to list items using the actionsSections property of the ListItem.

See also:

Sample - LayerList widget with actions

Example:

var layerList = new LayerList({
  view: view,
  // executes for each ListItem in the LayerList
  listItemCreatedFunction: function (event) {

    // The event object contains properties of the
    // layer in the LayerList widget.

    var item = event.item;

    if (item.title === "US Demographics") {
      // open the list item in the LayerList
      item.open = true;
      // change the title to something more descriptive
      item.title = "Population by county";
      // set an action for zooming to the full extent of the layer
      item.actionsSections = [[{
        title: "Go to full extent",
        className: "esri-icon-zoom-out-fixed",
        id: "full-extent"
      }]];
    }
  }
});

multipleSelectionEnabled Boolean

Indicates whether more than one list item may be selected by the user at a single time. You must first set selectionEnabled to true for this property to have an effect on the widget.

Selected items are available in the selectedItems property.

Default Value:false

See also:

selectionEnabled
selectedItems

Example:

layerList.selectionEnabled = true;
layerList.multipleSelectionEnabled = true;

operationalItems Collection<ListItem>readonly

A collection of ListItems representing operational layers. To hide layers from the LayerList widget, set the listMode property on the layer(s) to hide.

See also:

Layer.listMode

selectedItems Collection<ListItem>readonly

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

See also:

selectionEnabled

selectionEnabled Boolean

Indicates whether list items may be selected by the user. Selected items may be reordered in the list by dragging gestures with the mouse or touch screen, or with arrow keys on the keyboard.

Selected items are available in the selectedItems property.

Default Value:false

See also:

selectedItems

Example:

layerList.selectionEnabled = true;

statusIndicatorsVisible Boolean Since: ArcGIS API for JavaScript 4.5

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 LayerList
layerList.statusIndicatorsVisible = false;

view MapView|SceneView

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

viewModel LayerListViewModel

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 LayerListViewModel class to access all properties and methods on the widget.

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	LayerList

Method Details

classes(classNames){String}inherited 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:

classNames Array<(string|Array<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 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}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 listItemCreatedFunction property. See the example snippet in the listItemCreatedFunction documentation 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.

Event Overview

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

Event Details

trigger-action

Fires after the user clicks on an action or action toggle inside the LayerList 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.

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JavaScript API 4.14 API Reference

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LayerList

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JavaScript API 4.14 API Reference

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