ListItemPanel

AMD: require(["esri/widgets/LayerList/ListItemPanel"], (LayerListItemPanel) => { /* code goes here */ });
ESM: import LayerListItemPanel from "@arcgis/core/widgets/LayerList/ListItemPanel.js";
Class: esri/widgets/LayerList/ListItemPanel
Inheritance: ListItemPanel Widget Accessor
Since: ArcGIS Maps SDK for JavaScript 4.7

This class allows you to display custom content for each ListItem in the LayerList widget. ListItemPanel objects typically aren't constructed. Rather, they are modified using the listItemCreatedFunction property in the LayerList widget.

A common scenario for using ListItemPanel is to display a Legend widget within each list item.

For information about gaining full control of widget styles, see the Styling topic.
See also
Example
const layerList = new LayerList({
  view: view,
  listItemCreatedFunction: function(event){
    const item = event.item;
    // displays the legend for each layer list item
    item.panel = {
      content: "legend"
    };
  }
});

Property Overview

Any properties can be set, retrieved or listened to. See the Working with Properties topic.
Show inherited properties Hide inherited properties
Name Type Summary Class
String

Adds a CSS class used to style a node that represents the panel.

ListItemPanel
String|HTMLElement

The ID or node representing the DOM element containing the widget.

Widget
Widget|HTMLElement|String|Array

The content displayed in the ListItem panel.

ListItemPanel
String

The name of the class.

Accessor
Boolean

If true, disables the ListItem's panel so the user cannot open or interact with it.

ListItemPanel
Boolean

Indicates whether the panel's content should be rendered as a Calcite Flow Item.

ListItemPanel
String

Icon which represents the widget.

Widget
String

The unique ID assigned to the widget when the widget is created.

Widget
String

The URL or data URI of an image used to represent the panel.

ListItemPanel
String

The widget's label.

Widget
ListItem

The panel's parent ListItem that represents a layer in the map.

ListItemPanel
Boolean

Indicates if the panel's content is open and visible to the user.

ListItemPanel
String

The title of the panel.

ListItemPanel
Boolean

Indicates if the node containing the image or className is visible to the user.

ListItemPanel

Property Details

className

Property
className String

Adds a CSS class used to style a node that represents the panel. Clicking the node will open and close the panel. Typically, an icon font is used for this property. Esri Icon Fonts are automatically made available and can be used to represent this content. To use one of these provided icon fonts, you must prefix the class name with esri-. For example, the default icon font is esri-icon-layer-list.

Default Value:esri-icon-layer-list

container

Inherited
Property
container String|HTMLElement
Inherited from Widget

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 case 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"
});

content

Property
content Widget|HTMLElement|String|Array

The content displayed in the ListItem panel. This can be raw text, a Widget instance, an HTML Element, or an array of any of those elements.

If the text legend is used, then an instance of the Legend widget is placed in the content.

Example
const layerList = new LayerList({
  view: view,
  listItemCreatedFunction: function(event){
    const item = event.item;
    // displays the legend for each layer list item
    item.panel = {
      content: "legend"
    };
  }
});

declaredClass

Inherited
Property
declaredClass Stringreadonly
Inherited from Accessor

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

disabled

Property
disabled Boolean
Since: ArcGIS Maps SDK for JavaScript 4.25 ListItemPanel since 4.7, disabled added at 4.25.

If true, disables the ListItem's panel so the user cannot open or interact with it. The panel will be disabled by default if it does not have content or if it contains a legend with no active content in it.

Example
const layerList = new LayerList({
  view: view,
  listItemCreatedFunction: function(event){
    const item = event.item;
    if (!item.layer.visible){
      item.panel.disabled = true;
    }
  }
});

flowEnabled

Property
flowEnabled Boolean
Since: ArcGIS Maps SDK for JavaScript 4.29 ListItemPanel since 4.7, flowEnabled added at 4.29.

Indicates whether the panel's content should be rendered as a Calcite Flow Item. By default, the panel's content is rendered in the content-bottom slot. Flow is a calcite component that allows for drilling in and out of panels.

Default Value:false

icon

Inherited
Property
icon String
Inherited from Widget
Since: ArcGIS Maps SDK for JavaScript 4.27 Widget since 4.2, icon added at 4.27.

Icon which represents the widget. It is typically used when the widget is controlled by another one (e.g. in the Expand widget).

Default Value:null
See also

id

Inherited
Property
id String
Inherited from Widget

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.

image

Property
image String

The URL or data URI of an image used to represent the panel. This property will be used as a background image for the node. If neither image nor className are specified, a default icon default icon will display.

label

Inherited
Property
label String
Inherited from Widget
Since: ArcGIS Maps SDK for JavaScript 4.11 Widget since 4.2, label added at 4.11.

The widget's label.

This property is useful whenever the widget is controlled by another one (e.g. Expand)

listItem

Property
listItem ListItem

The panel's parent ListItem that represents a layer in the map.

open

Property
open Boolean

Indicates if the panel's content is open and visible to the user. This is different from the visible property, which is used for toggling the visibility of the icon used to control whether the content is expanded or collapsed.

Default Value:false
Example
const layerList = new LayerList({
  view: view,
  listItemCreatedFunction: function(event){
    const item = event.item;
    // displays the legend for each layer list item
    // The legend is open by default, but the user
    // is prevented from collapsing that content
    item.panel = {
      content: "legend",
      open: true,
      visible: false
    };
  }
});

title

Property
title String

The title of the panel. By default, this title matches the ListItem's title. Changing this value will not change the title of the ListItem in the LayerList.

visible

Property
visible Boolean

Indicates if the node containing the image or className is visible to the user. Setting this value to false will prevent the user from toggling the visibility of the panel's content. Use open to programmatically set the visibility of the panel's content.

Default Value:true
Example
const layerList = new LayerList({
  view: view,
  listItemCreatedFunction: function(event){
    const item = event.item;
    // displays the legend for each layer list item
    // The legend is open by default, but the user
    // is prevented from collapsing that content
    item.panel = {
      content: "legend",
      open: true,
      visible: false
    };
  }
});

Method Overview

Show inherited methods Hide inherited methods
Name Return Type Summary Class

Adds one or more handles which are to be tied to the lifecycle of the object.

Accessor
String

A utility method used for building the value for a widget's class property.

Widget

Destroys the widget instance.

Widget
Boolean

Emits an event on the instance.

Widget
Boolean

Indicates whether there is an event listener on the instance that matches the provided event name.

Widget
Boolean

Returns true if a named group of handles exist.

Accessor
Boolean

isFulfilled() may be used to verify if creating an instance of the class is fulfilled (either resolved or rejected).

Widget
Boolean

isRejected() may be used to verify if creating an instance of the class is rejected.

Widget
Boolean

isResolved() may be used to verify if creating an instance of the class is resolved.

Widget
Object

Registers an event handler on the instance.

Widget

Adds one or more handles which are to be tied to the lifecycle of the widget.

Widget

This method is primarily used by developers when implementing custom widgets.

Widget

Removes a group of handles owned by the object.

Accessor
Object

This method is primarily used by developers when implementing custom widgets.

Widget

Renders widget to the DOM immediately.

Widget

This method is primarily used by developers when implementing custom widgets.

Widget
Promise

when() may be leveraged once an instance of the class is created.

Widget

Method Details

addHandles

Inherited
Method
addHandles(handleOrHandles, groupKey)
Inherited from Accessor
Since: ArcGIS Maps SDK for JavaScript 4.25 Accessor 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();
Parameters
handleOrHandles WatchHandle|WatchHandle[]

Handles marked for removal once the object is destroyed.

groupKey *
optional

Key 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.

classes

Inherited
Method
classes(classNames){String}
Inherited from Widget

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.
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
Method
destroy()
Inherited from Widget

Destroys the widget instance.

emit

Inherited
Method
emit(type, event){Boolean}
Inherited from Widget

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

Inherited
Method
hasEventListener(type){Boolean}
Inherited from Widget

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.

hasHandles

Inherited
Method
hasHandles(groupKey){Boolean}
Inherited from Accessor
Since: ArcGIS Maps SDK for JavaScript 4.25 Accessor since 4.0, hasHandles added at 4.25.

Returns true if a named group of handles exist.

Parameter
groupKey *
optional

A group key.

Returns
Type 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");
}

isFulfilled

Inherited
Method
isFulfilled(){Boolean}
Inherited from Widget
Since: ArcGIS Maps SDK for JavaScript 4.19 Widget since 4.2, isFulfilled added at 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

Inherited
Method
isRejected(){Boolean}
Inherited from Widget
Since: ArcGIS Maps SDK for JavaScript 4.19 Widget since 4.2, isRejected added at 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

Inherited
Method
isResolved(){Boolean}
Inherited from Widget
Since: ArcGIS Maps SDK for JavaScript 4.19 Widget since 4.2, isResolved added at 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

Inherited
Method
on(type, listener){Object}
Inherited from Widget

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 Function

The 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

Inherited
Method
own(handleOrHandles)
Inherited from Widget
Since: ArcGIS Maps SDK for JavaScript 4.24 Widget since 4.2, own added at 4.24.
Deprecated since 4.28 Use addHandles() instead.

Adds one or more handles which are to be tied to the lifecycle of the widget. The handles will be removed when the widget is destroyed.

const handle = reactiveUtils.when(
  () => !view.updating,
  () => {
    wkidSelect.disabled = false;
  },
  { once: true}
);

this.own(handle); // Handle gets removed when the widget is destroyed.
Parameter
handleOrHandles WatchHandle|WatchHandle[]

Handles marked for removal once the widget is destroyed.

postInitialize

Inherited
Method
postInitialize()
Inherited from Widget

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

removeHandles

Inherited
Method
removeHandles(groupKey)
Inherited from Accessor
Since: ArcGIS Maps SDK for JavaScript 4.25 Accessor since 4.0, removeHandles added at 4.25.

Removes a group of handles owned by the object.

Parameter
groupKey *
optional

A group key or an array or collection of group keys to remove.

Example
obj.removeHandles(); // removes handles from default group

obj.removeHandles("handle-group");
obj.removeHandles("other-handle-group");

render

Inherited
Method
render(){Object}
Inherited from Widget

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
Method
renderNow()
Inherited from Widget

Renders widget to the DOM immediately.

scheduleRender

Inherited
Method
scheduleRender()
Inherited from Widget

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

when

Inherited
Method
when(callback, errback){Promise}
Inherited from Widget
Since: ArcGIS Maps SDK for JavaScript 4.19 Widget since 4.2, when added at 4.19.

when() may be leveraged once an instance of the class is created. This method takes two input parameters: a callback function and an errback function. The callback executes when the instance of the class loads. The errback executes if the instance of the class fails to load.

Parameters
callback Function
optional

The function to call when the promise resolves.

errback Function
optional

The function to execute when the promise fails.

Returns
Type Description
Promise Returns a new promise for the result of callback.
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
});

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