LayerList
require(["esri/widgets/LayerList"], function(LayerList) { /* code goes here */ });
esri/widgets/LayerList
The LayerList widget provides a way to display a list of layers, and switching on/off their visibility.
- See also:
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 Objectoptional
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
Name | 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 | 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 | |
Collection<ListItem> | A collection of ListItems representing operational layers. 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
The ID or node representing the DOM element containing the widget. This property can only be set once.
- Since: ArcGIS API for JavaScript 4.7
The name of the class. The declared class name is formatted as
esri.folder.className
.
When
true
, this property indicates whether the widget has been destroyed.
- iconClassStringreadonlySince: ArcGIS API 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.
- labelStringreadonlySince: ArcGIS API for JavaScript 4.7
The widget's default label.
- listItemCreatedFunctionSince: 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.
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" }]]; } } });
- operationalItemsreadonly
A collection of ListItems representing operational layers.
- See also:
- statusIndicatorsVisibleBooleanSince: 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;
- viewModel
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
Name | Return Type | Summary | Class | |
---|---|---|---|---|
String | A utility method used for building the value for a widget's | more details | Widget | |
Destroys the widget instance. more details | more details | Widget | ||
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
- 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.Prior to version 4.7, there were various approaches towards setting CSS classes. These were dependent upon variables, such as whether the classes were:
- a single static class,
- multiple static classes, or
- dynamic classes.
This helper method takes all of these approaches into account and simplifies it to use one single pattern to accommodate these multiple approaches.
Parameter: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
Destroys the widget instance.
- emit(type, event)inheritedSince: 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 StringThe name of the event.
event ObjectThe event payload.
Indicates whether there is an event listener on the instance that matches the provided event name.
Parameter:type StringThe name of the event.
Returns:Type Description Boolean Returns true if the class supports the input event.
Registers an event handler on the instance. Call this method to hook an event with a listener.
Parameters:type StringThe name of event to listen for.
listener FunctionThe 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.Property Type Description remove Function When called, removes the listener from the event. - See also:
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.
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|ActionToggleThe action to execute.
item ListItemAn 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 ObjectAn object containing a list item created by the LayerList.
Specification:item 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.
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 ListItemAn item associated with the action.