Add a feature layer from a portal item

Learn how to use an ArcGIS portal item to access and display a feature layer in a map.

add a feature layer from a portal item

You can host a variety of geographic data and other resources using ArcGIS Online. These portal items can also define how the data is presented. A web map or web scene, for example, not only defines the layers for a map or scene, but also how layers are symbolized, the minimum and/or maximum scales at which they display, and several other properties. Likewise, a hosted feature layer contains the data for the layer and also defines the symbols and other display properties for how it is presented. When you add a map, scene, or layer from a portal item to your ArcGIS Runtime app, everything that has been saved with the item is applied in your app. Adding portal items to your ArcGIS Runtime app rather than creating them programmatically saves you from writing a lot of code, and can provide consistency across apps that use the same data.

In this tutorial, you will add a hosted feature layer to display trailheads in the Santa Monica Mountains of Southern California. The hosted layer defines the trailhead locations (points) as well as the symbols used to display them.

Prerequisites

The following are required for this tutorial:

  1. An ArcGIS account to access your API keys. If you don't have an account, sign up for free.
  2. Your system meets the system requirements.

Steps

Open the Xcode project

  1. To start the tutorial, complete the Display a map tutorial or download and unzip the solution.

  2. Open the .xcodeproj file in Xcode.

  3. If you downloaded the solution project, set your API key.

    An API Key enables access to services, web maps, and web scenes hosted in ArcGIS Online.

    1. Go to your developer dashboard to get your API key. For these tutorials, use your default API key. It is scoped to include all of the services demonstrated in the tutorials.

    2. In Xcode, in the Project Navigator, click AppDelegate.swift.

    3. In the editor, set the APIKey property on the AGSArcGISRuntimeEnvironment with your API key.


      AppDelegate.swift
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          func application(_ application: UIApplication,
                           didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
              // Note: it is not best practice to store API keys in source code.
              // The API key is referenced here for the convenience of this tutorial.
      
              AGSArcGISRuntimeEnvironment.apiKey = "YOUR_API_KEY"
      
              return true
          }
      
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Add a feature layer to the map

  1. Open the ViewController.swift file, update the setupMap() method to create an AGSPortal object and an AGSPortalItem object referencing the feature layer.

    Each portal item has a unique itemID, 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.

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         // Init map
         let map = AGSMap(basemapStyle: .arcGISTopographic)
         // Set mapView's view point
         mapView.setViewpoint(AGSViewpoint(latitude: 34.027, longitude: -118.805, scale: 100000))
    
         // *** ADD ***
         let portal = AGSPortal(url: URL(string: "https://www.arcgis.com")!, loginRequired: false)
         let item = AGSPortalItem(portal: portal, itemID: "2e4b3df6ba4b44969a3bc9827de746b3")
  2. Create an AGSFeatureLayer object from the portal item and a layer ID. Add the layer to the map's operational layers.

    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.

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         let item = AGSPortalItem(portal: portal, itemID: "2e4b3df6ba4b44969a3bc9827de746b3")
    
         // *** ADD ***
         let layer = AGSFeatureLayer(item: item, layerID: 0)
         mapView.map!.operationalLayers.add(layer)
  3. Press <Command+R> to run the app.

    If you are using the Xcode simulator your system must meet these minimum requirements: macOS Big Sur 11.3, Xcode 13, iOS 13. If you are using a physical device, then refer to the system requirements.

Your app should display a map with the trailheads centered on the Santa Monica Mountains. Compare your solution with our completed solution project.

What's next?

Learn how to use additional API features, ArcGIS location services, and ArcGIS tools in these tutorials:

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