ListItemPanel | API Reference | ArcGIS Maps SDK for JavaScript 4.31

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. This allows users to create a legend for each layer in the map simply by adding the string "legend" as the content.

See also

Example

const layerList = new LayerList({
  view: view,
  listItemCreatedFunction: function(event){
    const { item } = event;
    // 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 Watch for changes topic.

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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
LayerListItemPanelContent\|LayerListItemPanelContent []	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 panel.	ListItemPanel
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 whether the ListItemPanel is visible.	ListItemPanel

Property Details

className Property className String Deprecated since version 4.30. Use icon

Adds a CSS class used to style a node that represents the panel. Clicking the node will open and close the panel.

Default Value:null

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 LayerListItemPanelContent |LayerListItemPanelContent[]

The content displayed in the ListItem panel. This can be a String, a Widget instance, an HTMLElement, or an Array of any of those elements.

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

Example

const layerList = new LayerList({
  view: view,
  listItemCreatedFunction: (event) => {
    const { item } = event;
    // 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: (event) => {
    const { item } = event;
    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 Property icon String Since: ArcGIS Maps SDK for JavaScript 4.27 ListItemPanel since 4.7, icon added at 4.27.

Icon which represents the panel.

Default Value:null

See also

Calcite Icon Search

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, nor icon are specified, a 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.

Default Value:false

Example

const layerList = new LayerList({
  listItemCreatedFunction: async (event) => {
    const { item } = event;
    const { layer } = item;

   // add a legend as the content and open the panel by default
    item.panel = {
      content: "legend",
      open: true
    };
  },
  view
});

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 whether the ListItemPanel is visible.

If false, the list item panel will not be rendered in the HTML document.

Default Value:true

Example

const layerList = new LayerList({
  listItemCreatedFunction: async (event) => {
    const { item } = event;
    const { layer } = item;

    item.panel = {
      content: "legend",
      open: true
    };

    // hide the panel for a specific layer
    if (layer.title.includes("Confidential")) {
      item.panel.visible = false;
    }
  },
  view
});

Method Overview

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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
	Executes after widget is ready for rendering.	Widget
	Removes a group of handles owned by the object.	Accessor
Object	This method is implemented by subclasses for rendering.	Widget
	Renders widget to the DOM immediately.	Widget
	Schedules widget rendering.	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 dynamicClasses = {
    [css.flip]: this.flip,
    [css.primary]: this.primary
  };

  return (
    <div class={classes(css.root, css.mixin, dynamicClasses)} />
  );
}

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

type String|String []

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

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 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

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
});

Type Definitions

LayerListItemPanelContent Type Definition LayerListItemPanelContent Widget |HTMLElement |String

The content displayed in the ListItem panel. This can be a String, a Widget instance, or an HTMLElement.

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