AGSFeatureCollection Class Reference

Description

A lightweight collection of features.

Instances of this class represent a lightweight collection of features. The features in the collection are organized into tables, where all the features that belong to a table share the same attribute schema (fields), geometry type, and spatial reference. The feature collection may be created and stored as part of a map or as a separate item (of type AGSPortalItemTypeFeatureCollection) on ArcGIS Portal. You can also programmatically create an empty feature collection and then add tables and features to it.

Since

100

See also

AGSFeatureCollectionLayer to display features in the feature collection on a map or a scene.

Inheritance diagram for AGSFeatureCollection:

Instance Methods
(void)	- cancelLoad
(void)	- doCancelLoading
(void)	- doStartLoading:
(instancetype)	- initWithFeatureCollectionTables:
(instancetype)	- initWithItem:
(void)	- loadDidFinishWithError:
(void)	- loadWithCompletion:
(void)	- onLoadStatusChanged
(void)	- retryLoadWithCompletion:
(id< AGSCancelable >)	- saveAs:portal:tags:folder:itemDescription:thumbnail:completion:
(id< AGSCancelable >)	- saveWithCompletion:
(nullable id)	- toJSON:

Class Methods
(instancetype)	+ featureCollection
(instancetype)	+ featureCollectionWithFeatureCollectionTables:
(instancetype)	+ featureCollectionWithItem:
(nullable id< AGSJSONSerializable >)	+ fromJSON:error:

Properties
AGSItem *	item
NSError *	loadError
AGSLoadStatus	loadStatus
NSMutableArray< AGSFeatureCollectionTable * > *	tables
NSDictionary< NSString *, id > *	unknownJSON
NSDictionary< NSString *, id > *	unsupportedJSON

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).

featureCollection

+ (instancetype) featureCollection

Initialize an empty feature collection to which feature collection tables can be added

Returns

Initialized feature collection

Since

100

featureCollectionWithFeatureCollectionTables:

+ (instancetype) featureCollectionWithFeatureCollectionTables:

(NSArray< AGSFeatureCollectionTable * > *)

featureCollectionTables

Initialize the feature collection with the provided feature collection tables

Parameters

featureCollectionTables

containing tables which organize the features for the feature collection

Returns

Initialized feature collection

Since

100

featureCollectionWithItem:

+ (instancetype) featureCollectionWithItem:

(AGSItem *)

item

Initialize the feature collection with the provided item. The item must be of type AGSPortalItemTypeFeatureCollection.

Parameters

item	of type AGSPortalItemTypeFeatureCollection that represents the feature collection

Returns

Initialized feature collection

Since

100

fromJSON:error:

+ (nullable id<AGSJSONSerializable>) fromJSON: (id)  JSONObject error: (NSError **)  error

staticrequiredinherited

Initializes and returns an object from its JSON representation.

Parameters

JSONObject	NSDictionary or NSArray containing the JSON.
error	encountered during the operation, if any.

Since

100

initWithFeatureCollectionTables:

- (instancetype) initWithFeatureCollectionTables:

(NSArray< AGSFeatureCollectionTable * > *)

featureCollectionTables

Initialize the feature collection with the provided feature collection tables

Parameters

featureCollectionTables

containing tables which organize the features for the feature collection

Returns

Initialized feature collection

Since

100

initWithItem:

- (instancetype) initWithItem:

(AGSItem *)

item

Initialize the feature collection with the provided item. The item must be of type AGSPortalItemTypeFeatureCollection.

Parameters

item	of type AGSPortalItemTypeFeatureCollection that represents the feature collection

Returns

Initialized feature collection

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

toJSON:

- (nullable id) toJSON: (NSError **)  error

requiredinherited

Returns JSON representation for this object.

Parameters

error

encountered during the operation, if any.

Returns

NSDictionary or NSArray containing the JSON.

Since

100

Reimplemented in AGSPortalItem.

Property Documentation

item

- (AGSItem*) item

readwritenonatomicstrong

The item that this feature collection represents.

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

tables

- (NSMutableArray<AGSFeatureCollectionTable*>*) tables

readnonatomicstrong

The individual tables that are part of this feature collection. The tables provide a way to organize and group features that have the attribute schema (fields), geometry type, and spatial reference.

Since

100

unknownJSON

- (NSDictionary<NSString*,id>*) unknownJSON

readrequirednonatomiccopyinherited

A dictionary of values that was in the source JSON but was unparsed by API.

Returns

NSDictionary containing the unknown JSON.

Since

100

unsupportedJSON

- (NSDictionary<NSString*,id>*) unsupportedJSON

readnonatomiccopyinherited

A dictionary of values that are supported by the REST API, but not exposed through the SDK API.

Returns

NSDictionary containing the unsupported JSON.

Since

100