UnknownLayer
esri/layers/UnknownLayer
Represents a layer whose type could not be determined. For example, when loading a layer from a URL and the layer type cannot be determined, then it is represented as an instance of this class.
An instance of this class may also be used when loading a WebMap or a WebScene. If the service of one of the layers in the WebMap/WebScene is not available and the layer type cannot be determined, then it is represented as an UnknownLayer. It is important to note that constructing layers from this class is not supported.
Property Overview
Name | Type | Summary | Class | |
---|---|---|---|---|
String | The name of the class. more details | more details | Accessor | |
Extent | The full extent of the layer. more details | more details | Layer | |
String | The unique ID assigned to the layer. more details | more details | Layer | |
String | Indicates how the layer should display in the LayerList widget. more details | more details | Layer | |
Boolean | Indicates whether the layer's resources have loaded. more details | more details | Layer | |
Error | The Error object returned if an error occurred while loading. more details | more details | Layer | |
String | Represents the status of a load operation. more details | more details | Layer | |
Object[] | A list of warnings which occurred while loading. more details | more details | Layer | |
Number | The opacity of the layer. more details | more details | Layer | |
String | The title of the layer used to identify it in places such as the Legend and LayerList widgets. more details | more details | Layer | |
String | For UnknownLayer the type is | more details | UnknownLayer | |
Boolean | Indicates if the layer is visible in the View. more details | more details | Layer |
Property Details
- Since: ArcGIS API for JavaScript 4.7
The name of the class. The declared class name is formatted as
esri.folder.className
.
The full extent of the layer. By default, this is worldwide. This property may be used to set the extent of the view to match a layer's extent so that its features appear to fill the view. See the sample snippet below.
Example:// Once the layer loads, set the view's extent to the layer's fullextent layer.when(function(){ view.extent = layer.fullExtent; });
The unique ID assigned to the layer. If not set by the developer, it is automatically generated when the layer is loaded.
Indicates how the layer should display in the LayerList widget. The possible values are listed below.
Value Description show The layer is visible in the table of contents. hide The layer is hidden in the table of contents. hide-children If the layer is a GroupLayer, hide the children layers from the table of contents. - Default Value:show
Indicates whether the layer's resources have loaded. When
true
, all the properties of the object can be accessed.- Default Value:false
The Error object returned if an error occurred while loading.
- Default Value:null
Represents the status of a load operation.
Value Description not-loaded The object's resources have not loaded. loading The object's resources are currently loading. loaded The object's resources have loaded without errors. failed The object's resources failed to load. See loadError for more details. - Default Value:not-loaded
A list of warnings which occurred while loading.
The opacity of the layer. This value can range between
1
and0
, where0
is 100 percent transparent and1
is completely opaque.- Default Value:1
Example:// Makes the layer 50% transparent layer.opacity = 0.5;
- typeStringreadonly
For UnknownLayer the type is
unknown
.
Indicates if the layer is visible in the View. When
false
, the layer may still be added to a Map instance that is referenced in a view, but its features will not be visible in the view.- Default Value:true
Example:// The layer is no longer visible in the view layer.visible = false;
Method Overview
Name | Return Type | Summary | Class | |
---|---|---|---|---|
Cancels a load() operation if it is already in progress. more details | more details | Layer | ||
Emits an event on the instance. more details | more details | Layer | ||
Promise<Object> | Fetches custom attribution data for the layer when it becomes available. more details | more details | Layer | |
Boolean | Indicates whether there is an event listener on the instance that matches the provided event name. more details | more details | Layer | |
Boolean |
| more details | Layer | |
Boolean |
| more details | Layer | |
Boolean |
| more details | Layer | |
Promise | Loads the resources referenced by this class. more details | more details | Layer | |
Object | Registers an event handler on the instance. more details | more details | Layer | |
Promise |
| more details | Layer |
Method Details
- 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.
Fetches custom attribution data for the layer when it becomes available.
Returns:Type Description Promise<Object> Resolves to an object containing custom attribution data for the layer.
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.
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()
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()
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.
Loads the resources referenced by this class. This method automatically executes for a View and all of the resources it references in Map if the view is constructed with a map instance.
This method must be called by the developer when accessing a resource that will not be loaded in a View.
Returns:Type Description Promise Resolves when the resources have loaded.
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); });
- Since: ArcGIS API for JavaScript 4.6
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 MapView, any class instance that is a promise may use then() in the same way var view = new MapView(); view.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 });
Event Overview
Name | Type | Summary | Class | |
---|---|---|---|---|
{view: View,layerView: LayerView} | Fires after the layer's LayerView is created and rendered in a view. more details | more details | Layer | |
{view: View,layerView: LayerView} | Fires after the layer's LayerView is destroyed and no longer renders in a view. more details | more details | Layer |
Event Details
- layerview-createinherited
Fires after the layer's LayerView is created and rendered in a view.
- Properties:
- view View
The view in which the
layerView
was created.layerView LayerViewThe LayerView rendered in the view representing the layer in
layer
. - See also:
Example:// This function will fire each time a layer view is created for this // particular view. layer.on("layerview-create", function(event){ // The LayerView for the layer that emitted this event event.layerView; });