Add a feature layer from a portal item

Before starting this tutorial:

1. You need an ArcGIS Location Platform or ArcGIS Online account.

2. Your system meets the system requirements.

Option 1: Develop the code

To start the tutorial, complete the Display a map tutorial. This creates a map to display the Santa Monica Mountains in California using the topographic basemap from the ArcGIS basemap styles service. You can choose to implement either API key authentication or user authentication.

Continue with the following instructions to use an ArcGIS portal item to access and display a feature layer in a map.

Add a feature layer to the map

1. Open the ContentView.swift file and update the map object. Create a PortalItem object referencing the feature layer by passing in the portal and item ID.

   More info

   Each portal item has a unique Item.ID, identified from its URL on ArcGIS Online.

   In your browser, go to the Trailheads Styled layer on ArcGIS Online and find the item ID at the end of the URL. It should be 2e4b3df6ba4b44969a3bc9827de746b3.

   The feature layer referenced with this portal item contains trailheads in and around the Santa Monica Mountains.

   ContentView.swift

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       @State private var map = {
           // Creates a map with the topographic basemap style.
           let map = Map(basemapStyle: .arcGISTopographic)
           // Sets the initial viewpoint to Malibu, California.
           map.initialViewpoint = Viewpoint(latitude: 34.027, longitude: -118.805, scale: 72_000)
   
           // Creates an anonymous portal item pointing to https://www.arcgis.com with an item ID.
           let portalItem = PortalItem(
               portal: .arcGISOnline(connection: .anonymous),
               id: Item.ID("2e4b3df6ba4b44969a3bc9827de746b3")!
           )
   
           return map
       }()
   

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2. Create a FeatureLayer object from the portal item and a layer ID. The layer ID uniquely identifies one of the layers from the portal item. Add the layer to the map's operational layers.

   More info

   A layer ID is required because a portal item may have more than one layer. For instance, when a feature service has 3 layers - trailheads (points), trails (polylines) and trail areas (polygons), the corresponding portal item would contain all three layers.

   ContentView.swift

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       @State private var map = {
           // Creates a map with the topographic basemap style.
           let map = Map(basemapStyle: .arcGISTopographic)
           // Sets the initial viewpoint to Malibu, California.
           map.initialViewpoint = Viewpoint(latitude: 34.027, longitude: -118.805, scale: 72_000)
   
           // Creates an anonymous portal item pointing to https://www.arcgis.com with an item ID.
           let portalItem = PortalItem(
               portal: .arcGISOnline(connection: .anonymous),
               id: Item.ID("2e4b3df6ba4b44969a3bc9827de746b3")!
           )
   
           // Creates a feature layer from the portal item and a layer ID.
           let layer = FeatureLayer(featureServiceItem: portalItem, layerID: 0)
           // Adds the layer to the map's operational layers.
           map.addOperationalLayer(layer)
   
           return map
       }()
   

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Run the solution

Press Command + R to run the app.

You should see a map of trail heads in the Santa Monica mountains. Tap, drag, and zoom on the map view to explore the map.

Option 2: Download the solution

1. Click the Download solution link under Solution and unzip the file to a location on your machine.

2. Open the .xcodeproj file in Xcode.

Since the downloaded solution does not contain authentication credentials, you must first set up authentication to create credentials, and then add the developer credentials to the solution.

Set developer credentials in the solution

To access the secure ArcGIS location services used in this tutorial, you must implement API key authentication or user authentication using an ArcGIS Location Platform or an ArcGIS Online account.

Set developer credentials

To allow your app users to access ArcGIS location services, pass the developer credentials that you created in the Set up authentication step to the application's ArcGISEnvironment.

Run the solution

Press Command + R to run the app.

You should see a map of trail heads in the Santa Monica mountains. Tap, drag, and zoom on the map view to explore the map.