ArcGIS Runtime SDK for iOS
100.15
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A container for other layers and group layers. It is used to represent datasets that are composed of multiple layers to be managed as a single layer with respect to display in a map or scene.
Group layers are designed for presentation of operational layers that are related by a theme. You can add several related operational child layers into a group layer so the layers can be displayed together. Suppose there are several feature layers that represent existing infrastructure projects (buildings, sidewalks, roads, and trees). You can add these feature layers into a single group layer called "Existing". Similarly assume there are also proposed infrastructure projects that are features in other layers. These layers can be added to a group layer called "Planned". You can manage the visibility of the existing or planned features as separate groups.
For the most part, group layers behave like any other layer in that:
The full extent of a group layer is derived asynchronously based on what information is available from the child layers. This means the full extent can change when child layers are added or removed. The full extent geometry will have the spatial reference of the first loaded child layer.
Group layers are not supported in web maps. Saving a map with a group layer to a web map flattens the operational layers. Group layers are supported in web scenes. The visual opacity property of the group layer affects the opacity of the child layers. The opacity of the child layers is a mathematical product of the individual child layer's opacity and the group layer's opacity. Opacity values range from 0.0
(transparent) to 1.0
(opaque). This means that setting the opacity of the group layer to 0.0
will make all child layers transparent [0 * AnyNumber = 0]. Likewise when the group layer opacity is 1.0
, will set the opacity of the child layers to their individual layer opacity [1 * AnyNumber = AnyNumber].
AGSLayer
Instance Methods | |
(void) | - cancelLoad |
(void) | - doCancelLoading |
(void) | - doStartLoading: |
(id< AGSCancelable >) | - fetchLegendInfosWithCompletion: |
(instancetype) | - initWithChildLayers: |
(BOOL) | - isEqualToLayer: |
(BOOL) | - isVisibleAtScale: |
(void) | - loadDidFinishWithError: |
(void) | - loadWithCompletion: |
(void) | - onLoadStatusChanged |
(void) | - retryLoadWithCompletion: |
Class Methods | |
(instancetype) | + groupLayer |
(instancetype) | + groupLayerWithChildLayers: |
Properties | |
NSString * | attribution |
BOOL | canChangeVisibility |
AGSEnvelope * | fullExtent |
BOOL | identifyEnabled |
AGSItem * | item |
NSString * | layerDescription |
NSString * | layerID |
NSMutableArray< AGSLayer * > * | layers |
NSError * | loadError |
AGSLoadStatus | loadStatus |
double | maxScale |
double | minScale |
NSString * | name |
float | opacity |
BOOL | showChildrenInLegend |
BOOL | showInLegend |
AGSSpatialReference * | spatialReference |
NSArray< id< AGSLayerContent > > * | subLayerContents |
void(^ | subLayerContentsChangedHandler )(void) |
AGSGroupVisibilityMode | visibilityMode |
BOOL | visible |
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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
- (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
.
Provided by category AGSLoadableBase(ForSubclassEyesOnly).
- (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.
retrying | flag that is true if this method was called from retryLoadWithCompletion: (AGSLoadable-p) . |
Provided by category AGSLoadableBase(ForSubclassEyesOnly).
- (id<AGSCancelable>) fetchLegendInfosWithCompletion: | (void(^)(NSArray< AGSLegendInfo * > *__nullable legendInfos, NSError *__nullable error)) | completion |
Fetches the array of legend infos (AGSLegendInfo
) for this layer.
+ (instancetype) groupLayer |
Creates a layer. Once the layer is created you will have to set the child layers by setting the AGSGroupLayer::layers
property.
+ (instancetype) groupLayerWithChildLayers: | (NSArray< AGSLayer * > *) | childLayers |
Creates a layer with child layers.
childLayers | An array of layers to combine into a group layer. |
AGSGroupLayer::layers
- (instancetype) initWithChildLayers: | (NSArray< AGSLayer * > *) | childLayers |
Creates a layer with child layers.
childLayers | An array of layers to combine into a group layer. |
AGSGroupLayer::layers
- (BOOL) isEqualToLayer: | (AGSLayer *) | other |
- (BOOL) isVisibleAtScale: | (double) | scale |
Check whether this layer is visible at a given scale.
- (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.
Provided by category AGSLoadableBase(ForSubclassEyesOnly).
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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.
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. |
- cancelLoad
to cancel loading - retryLoadWithCompletion:
to force reload - (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.
Provided by category AGSLoadableBase(ForSubclassEyesOnly).
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requiredinherited |
Tries to reload when an object has failed to load. This method should be called judiciously. It should be called when:
cancelLoad
and then this methodIf 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.
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. |
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readnonatomiccopyinherited |
Attribution information of the layer.
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readrequirednonatomicassigninherited |
Denotes whether the layer can change visibility or not.
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readnonatomicstronginherited |
Full extent of the layer.
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readnonatomicassigninherited |
Specifies whether the layer supports identify.
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readnonatomicstronginherited |
The item the layer has been created from.
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readwritenonatomiccopyinherited |
The layer's description.
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readwritenonatomiccopyinherited |
The layer's ID specified in the web map item of ArcGIS Online or an on-premises portal.
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readnonatomicstrong |
The child layers nested within this group layer.
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readnonatomicstronginherited |
The error that was encountered during the most recent load operation. Will be nil if the operation succeeded.
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readrequirednonatomicassigninherited |
Status of the load operation.
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readwritenonatomicassigninherited |
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.
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readwritenonatomicassigninherited |
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.
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readwritenonatomiccopyinherited |
The name of the layer.
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readwritenonatomicassigninherited |
The opacity of this layer as a value between 0 (fully transparent) and 1 (fully opaque). Default value is 1.
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readwritenonatomicassign |
Determines if the child layers should be shown in the map legend.
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readwritenonatomicassigninherited |
Indicates whether to show legend information.
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readnonatomicstronginherited |
The spatial reference of the layer.
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readnonatomiccopyinherited |
This layer's sub-layers.
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readwritenonatomiccopyinherited |
Block that is invoked when the sub layer contents changes.
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readwritenonatomicassign |
The visibility mode for the layers in a table of contents.
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readwritenonatomicassigninherited |
Denotes whether the layer is visible or not. The visibility changes can be monitored using Key-Value Observing (KVO).