AGSLayer Class Reference

Description

An abstract base class for all layers.

AGSLayer is the base class for all layer types. A layer is a representation of geographic data portrayed using symbols and text labels. Multiple layers can be 'stacked' to enhance the information displayed. Layers are displayed in an AGSMap inside an AGSMapView control. Layers are drawn bottom-to-top, so the first layer in a map's layer collection is drawn first (on the bottom) and each subsequent layer is drawn on top of it.

Layer type	2D/3D	Time-aware	Online/offline	Sources
Annotation layer (AGSAnnotationLayer)	2D	No	Both	ArcGIS feature service, portal item, mobile map package (.mmpk)
ArcGIS map image layer (AGSArcGISMapImageLayer)	Both	Yes	Online	ArcGIS map service
ArcGIS scene layer (AGSArcGISSceneLayer)	3D	No	Both	Scene service or scene package
ArcGIS tiled layer (AGSArcGISTiledLayer)	Both	No	Both	ArcGIS tile service, tile package (.tpk/.tpkx)
ArcGIS vector tiled layer (AGSArcGISVectorTiledLayer)	2D	No	Both	ArcGIS vector tile service, vector tile package (.vtpk)
Bing maps layer (AGSBingMapsLayer)	Both	No	Online	Bing maps
Dimension layer (DimensionLayer)	2D	Yes	Offline	Mobile map package (.mmpk)
ENC layer (AGSENCLayer)	2D	No	Offline	ENC exchange set, ENC cell
Feature collection layer (AGSFeatureCollectionLayer)	Both	No	Both	Portal item, web map, feature set / query result
Feature layer (AGSFeatureLayer)	Both	Yes	Both	ArcGIS feature service, WFS, shapefile, GeoPackage, geodatabase, OGC API Features
Group layer (AGSGroupLayer)	Both	No	Both	Other layers and group layers
KML layer (AGSKMLLayer)	Both	Yes	Both	KML file (.kml, .kmz)
Integrated mesh layer (AGSIntegratedMeshLayer)	3D	No	Both	Scene layer package (.slpk)
Mobile basemap layer (AGSMobileBasemapLayer)	2D	No	Offline	Mobile map package (.mmpk)
OpenStreetMap layer (AGSOpenStreetMapLayer)	Both	No	Online	OpenStreetMap.org
Point cloud layer (AGSPointCloudLayer)	3D	No	Both	Portal item, scene layer package (.slpk)
Raster layer (AGSRasterLayer)	Both	Yes	Both	GeoPackage, raster file, ArcGIS Image service
Subtype feature layer (AGSSubtypeFeatureLayer)	2D	No	Both	ArcGIS feature service, geodatabase
Web tiled layer (AGSWebTiledLayer)	Both	No	Online	Web tile service
WMS layer (AGSWMSLayer)	Both	Yes	Online	WMS service
WMTS layer (AGSWMTSLayer)	Both	No	Online	WMTS service

Since

100

Inheritance diagram for AGSLayer:

Instance Methods
(void)	- cancelLoad
(void)	- doCancelLoading
(void)	- doStartLoading:
(id< AGSCancelable >)	- fetchLegendInfosWithCompletion:
(BOOL)	- isEqualToLayer:
(BOOL)	- isVisibleAtScale:
(void)	- loadDidFinishWithError:
(void)	- loadWithCompletion:
(void)	- onLoadStatusChanged
(void)	- retryLoadWithCompletion:

Properties
NSString *	attribution
BOOL	canChangeVisibility
AGSEnvelope *	fullExtent
BOOL	identifyEnabled
AGSItem *	item
NSString *	layerDescription
NSString *	layerID
NSError *	loadError
AGSLoadStatus	loadStatus
double	maxScale
double	minScale
NSString *	name
float	opacity
BOOL	showInLegend
AGSSpatialReference *	spatialReference
NSArray< id< AGSLayerContent > > *	subLayerContents
void(^	subLayerContentsChangedHandler )(void)
BOOL	visible

Method Documentation

cancelLoad

- (void) cancelLoad

requiredinherited

Cancels loading if it is in progress, otherwise it does nothing. This should be called carefully because other objects could be waiting for loadWithCompletion: or retryLoadWithCompletion: to complete and this will call them all back with the error of NSUserCancelledError

Since

100

doCancelLoading

- (void) doCancelLoading

Never call this method directly. The framework calls this method on a background thread when cancelLoad (AGSLoadable-p) is called. It is meant to be overriden by subclasses. Subclasses should override this method to cancel loading their data and call loadDidFinishWithError: (AGSLoadableBase(ForSubclassEyesOnly)) at the end passing in an error representing NSUserCancelledError.

Since

100

Provided by category AGSLoadableBase(ForSubclassEyesOnly).

doStartLoading:

- (void) doStartLoading:

(BOOL)

retrying

Never call this method directly. The framework calls this method on a background thread when loadWithCompletion: (AGSLoadable-p) or retryLoadWithCompletion: (AGSLoadable-p) is called. It is meant to be overriden by subclasses. Subclasses should override this method to load their data and call loadDidFinishWithError: (AGSLoadableBase(ForSubclassEyesOnly)) upon completion, passing in the error if any.

Parameters

retrying

flag that is true if this method was called from retryLoadWithCompletion: (AGSLoadable-p).

Since

100

Provided by category AGSLoadableBase(ForSubclassEyesOnly).

fetchLegendInfosWithCompletion:

- (id<AGSCancelable>) fetchLegendInfosWithCompletion:

(void(^)(NSArray< AGSLegendInfo * > *__nullable legendInfos, NSError *__nullable error))

completion

Fetches the array of legend infos (AGSLegendInfo) for this layer.

Since

100

isEqualToLayer:

- (BOOL) isEqualToLayer:

(AGSLayer *)

other

isVisibleAtScale:

- (BOOL) isVisibleAtScale:

(double)

scale

Check whether this layer is visible at a given scale.

Since

100

loadDidFinishWithError:

- (void) loadDidFinishWithError:

(nullable NSError *)

error

Only subclasses should call this method in doStartLoading: (AGSLoadableBase(ForSubclassEyesOnly)) and doCancelLoading (AGSLoadableBase(ForSubclassEyesOnly)) when done loading or failed to load.

Since

100

Provided by category AGSLoadableBase(ForSubclassEyesOnly).

loadWithCompletion:

- (void) loadWithCompletion: (nullable void(^)(NSError *__nullable error))  completion

requiredinherited

Loads data for the object asynchronously. The completion block is invoked upon completion.

You can call this method any number of times, however only one attempt is made to load the data. If it is already loading, it will just continue to load (i.e. not force a reload). If it has already loaded successfully, the completion block will be invoked right away. If it has already failed to load, the completion block will be invoked right away with error previously encountered. This method supports multiple callers and will call them all back on completion. However, each caller's completion block will be invoked once and only once.

Parameters

completion

block that is invoked when object loads successfully or fails to load. An error is passed to the block if the object fails to load.

Note

The completion block is always invoked on the main thread.

Since

100

See also

- cancelLoad to cancel loading

- retryLoadWithCompletion: to force reload

onLoadStatusChanged

- (void) onLoadStatusChanged

Never call this method directly. The framework calls this method on a background thread when AGSLoadable::loadStatus changes is called. Subclasses can optionally implement this to know when their loading status has changed.

Since

100

Provided by category AGSLoadableBase(ForSubclassEyesOnly).

retryLoadWithCompletion:

- (void) retryLoadWithCompletion: (nullable void(^)(NSError *__nullable error))  completion

requiredinherited

Tries to reload when an object has failed to load. This method should be called judiciously. It should be called when:

1. you didn't have network connectivity earlier when it failed and you want to retry now that you have connectivity
2. the server was down earlier when it failed and you want to retry
3. the request is taking too long and you want to cancel it and retry, in which case you will first call cancelLoad and then this method

If the data hasn't started loading, it will start loading. If it is already loading, it will just continue to load. If it has already loaded successfully, calls back right away. If it has already failed to load, tries again. This method supports multiple callers and will call them all back on completion. However, each caller's completion block will be invoked once and only once.

Parameters

completion

block that is invoked when object loads successfully or fails to load. An error is passed to the block if the object fails to load.

Note

The completion block is always invoked on the main thread.

Since

100

Property Documentation

attribution

- (NSString*) attribution

readnonatomiccopy

Attribution information of the layer.

Since

100

canChangeVisibility

- (BOOL) canChangeVisibility

readrequirednonatomicassigninherited

Denotes whether the layer can change visibility or not.

Since

100

fullExtent

- (AGSEnvelope*) fullExtent

readnonatomicstrong

Full extent of the layer.

Since

100

identifyEnabled

- (BOOL) identifyEnabled

readnonatomicassign

Specifies whether the layer supports identify.

Since

100

item

- (AGSItem*) item

readnonatomicstrong

The item the layer has been created from.

Since

100

layerDescription

- (NSString*) layerDescription

readwritenonatomiccopy

The layer's description.

Since

100

layerID

- (NSString*) layerID

readwritenonatomiccopy

The layer's ID specified in the web map item of ArcGIS Online or an on-premises portal.

Since

100

loadError

- (NSError*) loadError

readnonatomicstronginherited

The error that was encountered during the most recent load operation. Will be nil if the operation succeeded.

Since

100

loadStatus

- (AGSLoadStatus) loadStatus

readrequirednonatomicassigninherited

Status of the load operation.

Since

100

maxScale

- (double) maxScale

readwritenonatomicassign

The maximum scale at which this layer is visible. If the map or scene is zoomed in beyond this scale, the layer will not be visible. A value of 0 means there is no maximum scale threshold and the layer will be visible at the smallest scale available for the map or scene.

Since

100

minScale

- (double) minScale

readwritenonatomicassign

The minimum scale at which this layer is visible. If the map or scene is zoomed out. beyond this scale, the layer will not be visible. A value of 0 means there is no minimum scale threshold and the layer will be visible at the largest scale available for the map or scene.

Since

100

name

- (NSString*) name

readwritenonatomiccopy

The name of the layer.

Since

100

opacity

- (float) opacity

readwritenonatomicassign

The opacity of this layer as a value between 0 (fully transparent) and 1 (fully opaque). Default value is 1.

Since

100

showInLegend

- (BOOL) showInLegend

readwritenonatomicassigninherited

Indicates whether to show legend information.

Since

100

spatialReference

- (AGSSpatialReference*) spatialReference

readnonatomicstrong

The spatial reference of the layer.

Since

100

subLayerContents

- (NSArray<id<AGSLayerContent> >*) subLayerContents

readnonatomiccopyinherited

This layer's sub-layers.

Since

100

subLayerContentsChangedHandler

- (void(^ subLayerContentsChangedHandler) (void))

readwritenonatomiccopyinherited

Block that is invoked when the sub layer contents changes.

Note

The block will be invoked on the same thread on which the event occurred, which could be any arbitrary thread. You need to dispatch any UI related work to the main thread.

Since

100

visible

- (BOOL) visible

readwritenonatomicassigninherited

Denotes whether the layer is visible or not. The visibility changes can be monitored using Key-Value Observing (KVO).

Since

100