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
.
- See also
let 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)
-
Parameterproperties Objectoptional
See the properties for a list of all the properties that may be passed into the constructor.
Example// typical usage let layerlist = new LayerList({ view: view });
Property Overview
Name | Type | Summary | Class |
---|---|---|---|
String|HTMLElement | The ID or node representing the DOM element containing the widget. more details | Widget | |
String | The name of the class. more details | Accessor | |
String | The widget's default CSS icon class. more details | LayerList | |
String | The unique ID assigned to the widget when the widget is created. more details | Widget | |
String | The widget's default label. more details | LayerList | |
ListItemCreatedHandler | A function that executes each time a ListItem is created. more details | LayerList | |
Boolean | Indicates whether more than one list item may be selected by the user at a single time. more details | LayerList | |
Collection<ListItem> | A collection of ListItems representing operational layers. more details | LayerList | |
Collection<ListItem> | A collection of selected ListItems representing operational layers selected by the user. more details | LayerList | |
Boolean | Indicates whether list items may be selected by the user. more details | LayerList | |
MapView|SceneView | A reference to the MapView or SceneView. more details | LayerList | |
LayerListViewModel | The view model for this widget. more details | LayerList | |
Boolean | Indicates whether the widget is visible. more details | Widget | |
VisibleElements | The visible elements that are displayed within the widget. more details | LayerList |
Property Details
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-
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" });
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Since: ArcGIS Maps SDK for JavaScript 4.7
-
The name of the class. The declared class name is formatted as
esri.folder.className
.
-
iconClass StringSince: ArcGIS Maps SDK for JavaScript 4.7
-
The widget's default CSS icon class.
-
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 StringSince: ArcGIS Maps SDK for JavaScript 4.7
-
The widget's default label.
-
listItemCreatedFunction ListItemCreatedHandlerSince: ArcGIS Maps SDK for JavaScript 4.4
-
A function that executes each time a ListItem is created. Use this function to add actions and panels to list items, and to override the default settings of a list item. Actions can be added to list items using the actionsSections property of the ListItem.
Examplelet 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. let 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
ExamplelayerList.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
-
selectedItems Collection<ListItem>
-
A collection of selected ListItems representing operational layers selected by the user.
- See also
-
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
ExamplelayerList.selectionEnabled = true;
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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.
-
Indicates whether the widget is visible.
If
false
, the widget will no longer be rendered in the web document. This may affect the layout of other elements or widgets in the document. For example, if this widget is the first of three widgets associated to the upper right hand corner of the view UI, then the other widgets will reposition when this widget is made invisible. For more information, refer to the CSS display value of"none"
.- Default Value:true
Example// Hides the widget in the view widget.visible = false;
-
visibleElements VisibleElementsSince: ArcGIS Maps SDK 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.
ExamplelayerList.visibleElements = { statusIndicators: false, errors: true };
Method Overview
Name | Return Type | Summary | Class |
---|---|---|---|
Adds one or more handles which are to be tied to the lifecycle of the object. more details | Accessor | ||
String | A utility method used for building the value for a widget's | Widget | |
Destroys the widget instance. more details | Widget | ||
Boolean | Emits an event on the instance. more details | Widget | |
Boolean | Indicates whether there is an event listener on the instance that matches the provided event name. more details | Widget | |
Boolean | Returns true if a named group of handles exist. more details | Accessor | |
Boolean |
| Widget | |
Boolean |
| Widget | |
Boolean |
| Widget | |
Object | Registers an event handler on the instance. more details | Widget | |
Adds one or more handles which are to be tied to the lifecycle of the widget. more details | Widget | ||
This method is primarily used by developers when implementing custom widgets. more details | Widget | ||
Removes a group of handles owned by the object. more details | Accessor | ||
Object | This method is primarily used by developers when implementing custom widgets. more details | Widget | |
Renders widget to the DOM immediately. more details | Widget | ||
This method is primarily used by developers when implementing custom widgets. more details | Widget | ||
Triggers the trigger-action event and executes the given action or action toggle. more details | LayerList | ||
Promise |
| Widget |
Method Details
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addHandles(handleOrHandles, groupKey)inheritedSince: ArcGIS Maps SDK for JavaScript 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();
ParametershandleOrHandles WatchHandle|WatchHandle[]Handles marked for removal once the object is destroyed.
groupKey *optionalKey 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.
-
Since: ArcGIS Maps SDK 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.Parameterrepeatable The class names.
ReturnsType 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
-
Destroys the widget instance.
-
Since: ArcGIS Maps SDK for JavaScript 4.5
-
Emits an event on the instance. This method should only be used when creating subclasses of this class.
Parameterstype StringThe name of the event.
event ObjectoptionalThe event payload.
ReturnsType Description Boolean true
if a listener was notified
-
Indicates whether there is an event listener on the instance that matches the provided event name.
Parametertype StringThe name of the event.
ReturnsType Description Boolean Returns true if the class supports the input event.
-
Since: ArcGIS Maps SDK for JavaScript 4.25
-
Returns true if a named group of handles exist.
ParametergroupKey *optionalA group key.
ReturnsType 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"); }
-
Since: ArcGIS Maps SDK for JavaScript 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.ReturnsType Description Boolean Indicates whether creating an instance of the class has been fulfilled (either resolved or rejected).
-
Since: ArcGIS Maps SDK for JavaScript 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.ReturnsType Description Boolean Indicates whether creating an instance of the class has been rejected.
-
Since: ArcGIS Maps SDK for JavaScript 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.ReturnsType Description Boolean Indicates whether creating an instance of the class has been resolved.
-
Registers an event handler on the instance. Call this method to hook an event with a listener.
ParametersAn event or an array of events to listen for.
listener FunctionThe function to call when the event fires.
ReturnsType 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. Exampleview.on("click", function(event){ // event is the event handle returned after the event fires. console.log(event.mapPoint); });
-
own(handleOrHandles)inheritedSince: ArcGIS Maps SDK for JavaScript 4.24
-
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.
ParameterhandleOrHandles 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.
-
removeHandles(groupKey)inheritedSince: ArcGIS Maps SDK for JavaScript 4.25
-
Removes a group of handles owned by the object.
ParametergroupKey *optionalA group key or an array or collection of group keys to remove.
Exampleobj.removeHandles(); // removes handles from default group obj.removeHandles("handle-group"); obj.removeHandles("other-handle-group");
-
This method is primarily used by developers when implementing custom widgets. It must be implemented by subclasses for rendering.
ReturnsType Description Object The rendered virtual node.
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renderNow()inherited
-
Renders widget to the DOM immediately.
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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.
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triggerAction(action, item)
-
Triggers the trigger-action event and executes the given action or action toggle.
Parametersaction ActionButton|ActionToggleThe action to execute.
item ListItemAn item associated with the action.
-
Since: ArcGIS Maps SDK for JavaScript 4.19
-
when()
may be leveraged once an instance of the class is created. This method takes two input parameters: acallback
function and anerrback
function. Thecallback
executes when the instance of the class loads. Theerrback
executes if the instance of the class fails to load.Parameterscallback FunctionoptionalThe function to call when the promise resolves.
errback FunctionoptionalThe function to execute when the promise fails.
ReturnsType 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
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ListItemCreatedHandler(event)
-
Function definition for the listItemCreatedFunction property. See the example snippet in the listItemCreatedFunction documentation for more details.
Parametersevent ObjectAn object containing a list item created by the LayerList.
Specificationitem ListItemA 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.
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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.
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 |
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 ListItemThe ListItem associated with the action.