The BasemapLayerList widget provides a way to display a list of Basemap layers and switch on/off their visibility. Base layers and reference layers are divided into separate sections. When editing is enabled, layers can be reordered by dragging and dropping between the lists and the title can be edited.
BasemapLayerList is very similar to our LayerList widget. See below samples for code inspiration:
Sample - LayerList widget
Sample - LayerList widget with actions
let basemapLayerList = new BasemapLayerList({
view: view
});
// Adds the widget below other elements in the top left corner of the view
view.ui.add(basemapLayerList, {
position: "top-left"
});
Constructors
-
new BasemapLayerList(properties)
-
Parameter:properties Objectoptional
See the properties for a list of all the properties that may be passed into the constructor.
Example:// typical usage let BasemapLayerList = new BasemapLayerList({ view: view });
Property Overview
Name | Type | Summary | Class | |
---|---|---|---|---|
Collection<ListItem> | more details A collection of ListItems representing the baseLayers. | more details | BasemapLayerList | |
ListItemCreatedHandler | more details Specifies a function that accesses each ListItem representing a base layer. | more details | BasemapLayerList | |
String | more details The current basemap's title. | more details | BasemapLayerList | |
String|HTMLElement | more details The ID or node representing the DOM element containing the widget. | more details | Widget | |
String | more details The name of the class. | more details | Accessor | |
Boolean | more details Indicates whether the basemap’s title, layer order and layer grouping can be edited by the user. | more details | BasemapLayerList | |
Number | more details Indicates the heading level to use for the widget title (i.e. | more details | BasemapLayerList | |
String | more details The widget's default CSS icon class. | more details | BasemapLayerList | |
String | more details The unique ID assigned to the widget when the widget is created. | more details | Widget | |
String | more details The widget's default label. | more details | BasemapLayerList | |
Boolean | more details Indicates whether more than one list item may be selected by the user at a single time. | more details | BasemapLayerList | |
Collection<ListItem> | more details A collection of ListItems representing the referenceLayers. | more details | BasemapLayerList | |
ListItemCreatedHandler | more details Specifies a function that accesses each ListItem representing a reference layer. | more details | BasemapLayerList | |
Collection<ListItem> | more details A collection of selected ListItems representing basemap layers selected by the user. | more details | BasemapLayerList | |
MapView|SceneView | more details | more details | BasemapLayerList | |
BasemapLayerListViewModel | more details The view model for this widget. | more details | BasemapLayerList | |
Boolean | more details Indicates whether the widget is visible. | more details | Widget | |
VisibleElements | more details The visible elements that are displayed within the widget. | more details | BasemapLayerList |
Property Details
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baseItems Collection<ListItem>readonly
-
A collection of ListItems representing the baseLayers.
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baseListItemCreatedFunction ListItemCreatedHandler
-
Specifies a function that accesses each ListItem representing a base layer. Each list item's modifiable properties can be updated within. Actions can be added to list items using the actionsSections property of the ListItem.
Example:let bmLayerList = new BasemapLayerList({ view: view, editingEnabled: true, baseListItemCreatedFunction: function(event){ baseListItem = event.item; if(baseListItem.title === "World Imagery_01"){ // clean up title baseListItem.title = "World Imagery"; // open the baseList item baseListItem.open = true; } } })
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basemapTitle String
-
The current basemap's title.
-
-
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" });
-
The name of the class. The declared class name is formatted as
esri.folder.className
.
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editingEnabled Boolean
-
Indicates whether the basemap’s title, layer order and layer grouping can be edited by the user. Any edits made will only be shown locally and will not be saved.
- Default Value:false
Example:// to enable editing basemapLayerList.editingEnabled = true;
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headingLevel NumberSince: ArcGIS API for JavaScript 4.20
-
Indicates the heading level to use for the widget title (i.e. "Basemap"). By default, this is rendered as a level 2 heading (e.g.
<h2>Basemap</h2>
). Depending on the widget's placement in your app, you may need to adjust this heading for proper semantics. This is important for meeting accessibility standards.- Default Value:2
- See also:
Example:// the widget title will render as an <h3> basemapLayerList.headingLevel = 3;
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iconClass String
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The widget's default CSS icon class.
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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.
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label String
-
The widget's default label.
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multipleSelectionEnabled Boolean
-
Indicates whether more than one list item may be selected by the user at a single time. Selected items are available in the selectedItems property.
- Default Value:false
- See also:
Example:basemapLayerList.multipleSelectionEnabled = true;
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referenceItems Collection<ListItem>readonly
-
A collection of ListItems representing the referenceLayers.
-
referenceListItemCreatedFunction ListItemCreatedHandler
-
Specifies a function that accesses each ListItem representing a reference layer. Each list item's modifiable properties can be updated within. Actions can be added to list items using the actionsSections property of the ListItem.
Example:let bmLayerList = new BasemapLayerList({ view: view, editingEnabled: true, referenceListItemCreatedFunction: function(event){ referenceListItem = event.item; if(referenceListItem.title === "World Imagery_01_reference_layer"){ // clean up title referenceListItem.title = "Reference layer"; // open the baseList item referenceListItem.open = true; } } })
-
selectedItems Collection<ListItem>
-
A collection of selected ListItems representing basemap layers selected by the user.
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viewModel BasemapLayerListViewModel
-
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 BasemapLayerListViewModel 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 VisibleElementsautocastSince: ArcGIS API 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.
Example:basemapLayerList.visibleElements = { statusIndicators: false };
Method Overview
Name | Return Type | Summary | Class | |
---|---|---|---|---|
String | more details A utility method used for building the value for a widget's | more details | Widget | |
more details Destroys the widget instance. | more details | Widget | ||
Boolean | more details Emits an event on the instance. | more details | Widget | |
Boolean | more details Indicates whether there is an event listener on the instance that matches the provided event name. | more details | Widget | |
Boolean | more details
| more details | Widget | |
Boolean | more details
| more details | Widget | |
Boolean | more details
| more details | Widget | |
Object | more details Registers an event handler on the instance. | more details | Widget | |
more details Widget teardown helper. | more details | Widget | ||
more details This method is primarily used by developers when implementing custom widgets. | more details | Widget | ||
Object | more details This method is primarily used by developers when implementing custom widgets. | more details | Widget | |
more details Renders widget to the DOM immediately. | more details | Widget | ||
more details This method is primarily used by developers when implementing custom widgets. | more details | Widget | ||
more details Triggers the trigger-action event and executes the given action or action toggle. | more details | BasemapLayerList | ||
Promise | more details
| more details | Widget |
Method Details
-
A utility method used for building the value for a widget's
class
property. This aids in simplifying CSS class setup.Parameter:repeatable The class names.
Returns:Type Description String The computed class name. - See also:
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)} /> ); }
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destroy()inherited
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Destroys the widget instance.
-
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 ObjectoptionalThe event payload.
Returns:Type Description Boolean true
if a listener was notified
-
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.
-
Since: ArcGIS API 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.Returns:Type Description Boolean Indicates whether creating an instance of the class has been fulfilled (either resolved or rejected).
-
Since: ArcGIS API 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.Returns:Type Description Boolean Indicates whether creating an instance of the class has been rejected.
-
Since: ArcGIS API for JavaScript 4.19
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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.
-
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 FunctionThe 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); });
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own(handles)inherited
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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.
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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.
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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.
Parameters:action ActionButton|ActionToggleThe action to execute.
item ListItemAn item associated with the action.
-
Since: ArcGIS API 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.Parameters:callback FunctionoptionalThe function to call when the promise resolves.
errback FunctionoptionalThe function to execute when the promise fails.
Returns:Type Description Promise Returns a new promise for the result of callback
that may be used to chain additional functions.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 baseListItemCreatedFunction and referenceListItemCreatedFunction properties. See the example snippets in the documentations for those properties 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.
-
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.
- Properties:
-
statusIndicators Boolean
Indicates whether to the status indicators will be displayed. Default is
true
.baseLayers BooleanIndicates whether to the base layers will be displayed. Default is
true
.referenceLayers BooleanIndicates whether to the reference layers will be displayed. Default is
true
.
Event Overview
Name | Type | Summary | Class | |
---|---|---|---|---|
{action: ActionButton,ActionToggle,item: ListItem} |
more details
Fires after the user clicks on an action or action toggle inside the BasemapLayerList widget. |
more details | BasemapLayerList |
Event Details
-
trigger-action
-
Fires after the user clicks on an action or action toggle inside the BasemapLayerList 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.