Display an offline map (Custom)

Learn how to download and display an offline map for a user-defined geographical area of a web map.

display offline map custom frame

Offline maps allow users to continue working when network connectivity is poor or lost. If a web map is enabled for offline use, a user can request that ArcGIS generates an offline map for a specified geographic area of interest.

In this tutorial, you will download an offline map for an area of interest from the web map of the stormwater network within Naperville, IL, USA. You can then use this offline map without a network connection.

To learn how to enable your web map for offline use, see the Offline enable a web map tutorial.

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.
  3. The ArcGIS Runtime API for iOS is installed.

Steps

Open an Xcode project

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

  2. Open the .xcodeproj file in Xcode.

Set the 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
    Change line
                                       
    // Copyright 2020 Esri
    //
    // Licensed under the Apache License, Version 2.0 (the "License");
    // you may not use this file except in compliance with the License.
    // You may obtain a copy of the License at
    //
    //   https://www.apache.org/licenses/LICENSE-2.0
    //
    // Unless required by applicable law or agreed to in writing, software
    // distributed under the License is distributed on an "AS IS" BASIS,
    // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    // See the License for the specific language governing permissions and
    // limitations under the License.
    
    
    import UIKit
    
    import ArcGIS
    
    
    @UIApplicationMain
    class AppDelegate: UIResponder, UIApplicationDelegate {
        var window: UIWindow?
    
        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
        }
    
    }
    

Get the web map item ID

You can use ArcGIS tools to create and view web maps. Use the Map Viewer to identify the web map item ID. This item ID will be used later in the tutorial.

  1. Go to the Naperville water network in the Map Viewer in ArcGIS Online. This web map displays stormwater network within Naperville, IL, USA.
  2. Make a note of the item ID at the end of the browser's URL. The item ID should be acc027394bc84c2fb04d1ed317aac674

Display the web map

You can display a web map using the web map's item ID. Create an AGSMap from the web map's AGSPortalItem, and display it in your app's AGSMapView.

  1. In Xcode, in the Project Navigator, click ViewController.swift.

  2. In the editor, modify the setupMap() function. Provide the web map's item ID.

    ViewController.swift
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    // Copyright 2021 Esri.
    //
    // Licensed under the Apache License, Version 2.0 (the "License");
    // you may not use this file except in compliance with the License.
    // You may obtain a copy of the License at
    //
    //   https://www.apache.org/licenses/LICENSE-2.0
    //
    // Unless required by applicable law or agreed to in writing, software
    // distributed under the License is distributed on an "AS IS" BASIS,
    // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    // See the License for the specific language governing permissions and
    // limitations under the License.
    
    import UIKit
    import ArcGIS
    
    
    class ViewController: UIViewController, AGSGeoViewTouchDelegate {
        @IBOutlet weak var mapView: AGSMapView!
    
        var offlineMapTask: AGSOfflineMapTask!
        var generateJob: AGSGenerateOfflineMapJob!
    
        var observation: NSKeyValueObservation?
    
        private func setupMap() {
            let portal = AGSPortal.arcGISOnline(withLoginRequired: false)
    
            let itemID = "acc027394bc84c2fb04d1ed317aac674"
    
            let portalItem = AGSPortalItem(portal: portal, itemID: itemID)
            let map = AGSMap(item: portalItem)
    
            mapView.map = map
    
            let offlineArea = AGSEnvelope(xMin: -88.1535, yMin: 41.7695, xMax: -88.1490, yMax: 41.7725, spatialReference: .wgs84())
    
            let simpleLineSymbol = AGSSimpleLineSymbol(style: .solid, color: .red,
                width: 3)
            let simpleFillSymbol = AGSSimpleFillSymbol(
                style: .solid,
                color: .clear,
                outline: simpleLineSymbol)
            let graphic = AGSGraphic(geometry: offlineArea, symbol: simpleFillSymbol, attributes: nil)
    
            let graphicOverlay = AGSGraphicsOverlay()
            self.mapView.graphicsOverlays.add(graphicOverlay)
    
            graphicOverlay.graphics.add(graphic)
    
            offlineMapTask = AGSOfflineMapTask(onlineMap: map)
    
            offlineMapTask.defaultGenerateOfflineMapParameters(withAreaOfInterest: offlineArea, completion: {[weak self] (parameters, error) in
                guard let self = self else { return }
                if let error = error {
                    print("Error fetching default parameters for the area of interest : \(error.localizedDescription)")
                        return
                    }
                    guard let parameters = parameters else { return }
    
                    parameters.updateMode = .noUpdates
    
                    let documentDirectory = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first!
                    let formattedDate = ISO8601DateFormatter().string(from: Date())
    
                    let downloadDirectory = documentDirectory.appendingPathComponent(formattedDate)
    
                    self.generateJob = self.offlineMapTask.generateOfflineMapJob(with: parameters, downloadDirectory: downloadDirectory)
    
                    let numberFormatter = NumberFormatter()
                    numberFormatter.numberStyle = .percent
    
                    self.observation = self.generateJob.progress.observe(\.fractionCompleted) { (progress, _) in
                            print("Percentage Completed: \(numberFormatter.string(from: NSNumber(value: progress.fractionCompleted)))")
                        }
    
                    var i = 0
                    self.generateJob.start(statusHandler: { (_) in
                        // Print Job messages to console.
                        while i < self.generateJob.messages.count {
                            print("Job message \(i): \(self.generateJob.messages[i].message)")
                            i += 1
                        }
                    })
    
                    { [weak self] (result, error) in
                        guard let self = self else { return }
                        if let error = error {
                            print("Error downloading the offline map: \(error)")
                            return
                        }
                        guard let result = result else { return }
                        self.mapView.map = result.offlineMap
    
                    }
    
                })
    
        }
    
        override func viewDidLoad() {
            super.viewDidLoad()
            //AGSArcGISRuntimeEnvironment.apiKey = "YOUR-API-KEY"
            setupMap()
        }
    }
    

    The remaining code creates an AGSPortalItem using the AGSPortal that references ArcGIS Online, and the web map's itemID. The portalItem is used to create an AGSMap that is displayed in the app's AGSMapView.

  3. Press <Command+R> to run the app.

    If you are using the Xcode simulator your system must meet these minimum requirements: macOS Catalina, Xcode 11, iOS 13. If you are using a physical device, then refer to the system requirements.

You should see a map of the stormwater network within Naperville, IL, USA. Pinch, drag, and double-tap the map view to explore the web map.

Specify an area of the web map to take offline

You can specify an area of the web map to take offline using either an envelope or a polygon.

  1. Modify the setupMap() function. Create an AGSEnvelope to define the area to take offline.

    ViewController.swift
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    // Copyright 2021 Esri.
    //
    // Licensed under the Apache License, Version 2.0 (the "License");
    // you may not use this file except in compliance with the License.
    // You may obtain a copy of the License at
    //
    //   https://www.apache.org/licenses/LICENSE-2.0
    //
    // Unless required by applicable law or agreed to in writing, software
    // distributed under the License is distributed on an "AS IS" BASIS,
    // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    // See the License for the specific language governing permissions and
    // limitations under the License.
    
    import UIKit
    import ArcGIS
    
    
    class ViewController: UIViewController, AGSGeoViewTouchDelegate {
        @IBOutlet weak var mapView: AGSMapView!
    
        var offlineMapTask: AGSOfflineMapTask!
        var generateJob: AGSGenerateOfflineMapJob!
    
        var observation: NSKeyValueObservation?
    
        private func setupMap() {
            let portal = AGSPortal.arcGISOnline(withLoginRequired: false)
    
            let itemID = "acc027394bc84c2fb04d1ed317aac674"
    
            let portalItem = AGSPortalItem(portal: portal, itemID: itemID)
            let map = AGSMap(item: portalItem)
    
            mapView.map = map
    
            let offlineArea = AGSEnvelope(xMin: -88.1535, yMin: 41.7695, xMax: -88.1490, yMax: 41.7725, spatialReference: .wgs84())
    
            let simpleLineSymbol = AGSSimpleLineSymbol(style: .solid, color: .red,
                width: 3)
            let simpleFillSymbol = AGSSimpleFillSymbol(
                style: .solid,
                color: .clear,
                outline: simpleLineSymbol)
            let graphic = AGSGraphic(geometry: offlineArea, symbol: simpleFillSymbol, attributes: nil)
    
            let graphicOverlay = AGSGraphicsOverlay()
            self.mapView.graphicsOverlays.add(graphicOverlay)
    
            graphicOverlay.graphics.add(graphic)
    
            offlineMapTask = AGSOfflineMapTask(onlineMap: map)
    
            offlineMapTask.defaultGenerateOfflineMapParameters(withAreaOfInterest: offlineArea, completion: {[weak self] (parameters, error) in
                guard let self = self else { return }
                if let error = error {
                    print("Error fetching default parameters for the area of interest : \(error.localizedDescription)")
                        return
                    }
                    guard let parameters = parameters else { return }
    
                    parameters.updateMode = .noUpdates
    
                    let documentDirectory = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first!
                    let formattedDate = ISO8601DateFormatter().string(from: Date())
    
                    let downloadDirectory = documentDirectory.appendingPathComponent(formattedDate)
    
                    self.generateJob = self.offlineMapTask.generateOfflineMapJob(with: parameters, downloadDirectory: downloadDirectory)
    
                    let numberFormatter = NumberFormatter()
                    numberFormatter.numberStyle = .percent
    
                    self.observation = self.generateJob.progress.observe(\.fractionCompleted) { (progress, _) in
                            print("Percentage Completed: \(numberFormatter.string(from: NSNumber(value: progress.fractionCompleted)))")
                        }
    
                    var i = 0
                    self.generateJob.start(statusHandler: { (_) in
                        // Print Job messages to console.
                        while i < self.generateJob.messages.count {
                            print("Job message \(i): \(self.generateJob.messages[i].message)")
                            i += 1
                        }
                    })
    
                    { [weak self] (result, error) in
                        guard let self = self else { return }
                        if let error = error {
                            print("Error downloading the offline map: \(error)")
                            return
                        }
                        guard let result = result else { return }
                        self.mapView.map = result.offlineMap
    
                    }
    
                })
    
        }
    
        override func viewDidLoad() {
            super.viewDidLoad()
            //AGSArcGISRuntimeEnvironment.apiKey = "YOUR-API-KEY"
            setupMap()
        }
    }
    
    This web map uses a Web Mercator spatial reference. You can define an envelope or polygon for the offline area using a different spatial reference, such as WGS84. Always ensure that the envelope's coordinate values are valid for its spatial reference.
  2. Display the area of the web map to be taken offline using a transparent graphic with a red outline.

    Create an AGSGraphic using the offlineArea and give it a transparent AGSSimpleFillSymbol with a red AGSSimpleLineSymbol outline.

    Create a AGSGraphicsOverlay and add it to the map view's collection of graphics overlays. Add the graphic to the graphicsOverlay's collection of graphics.

    ViewController.swift
    Add line.Add line.Add line.Add line.Add line.Add line.Add line.Add line.Add line.Add line.Add line.Add line.
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    // Copyright 2021 Esri.
    //
    // Licensed under the Apache License, Version 2.0 (the "License");
    // you may not use this file except in compliance with the License.
    // You may obtain a copy of the License at
    //
    //   https://www.apache.org/licenses/LICENSE-2.0
    //
    // Unless required by applicable law or agreed to in writing, software
    // distributed under the License is distributed on an "AS IS" BASIS,
    // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    // See the License for the specific language governing permissions and
    // limitations under the License.
    
    import UIKit
    import ArcGIS
    
    
    class ViewController: UIViewController, AGSGeoViewTouchDelegate {
        @IBOutlet weak var mapView: AGSMapView!
    
        var offlineMapTask: AGSOfflineMapTask!
        var generateJob: AGSGenerateOfflineMapJob!
    
        var observation: NSKeyValueObservation?
    
        private func setupMap() {
            let portal = AGSPortal.arcGISOnline(withLoginRequired: false)
    
            let itemID = "acc027394bc84c2fb04d1ed317aac674"
    
            let portalItem = AGSPortalItem(portal: portal, itemID: itemID)
            let map = AGSMap(item: portalItem)
    
            mapView.map = map
    
            let offlineArea = AGSEnvelope(xMin: -88.1535, yMin: 41.7695, xMax: -88.1490, yMax: 41.7725, spatialReference: .wgs84())
    
            let simpleLineSymbol = AGSSimpleLineSymbol(style: .solid, color: .red,
                width: 3)
            let simpleFillSymbol = AGSSimpleFillSymbol(
                style: .solid,
                color: .clear,
                outline: simpleLineSymbol)
            let graphic = AGSGraphic(geometry: offlineArea, symbol: simpleFillSymbol, attributes: nil)
    
            let graphicOverlay = AGSGraphicsOverlay()
            self.mapView.graphicsOverlays.add(graphicOverlay)
    
            graphicOverlay.graphics.add(graphic)
    
            offlineMapTask = AGSOfflineMapTask(onlineMap: map)
    
            offlineMapTask.defaultGenerateOfflineMapParameters(withAreaOfInterest: offlineArea, completion: {[weak self] (parameters, error) in
                guard let self = self else { return }
                if let error = error {
                    print("Error fetching default parameters for the area of interest : \(error.localizedDescription)")
                        return
                    }
                    guard let parameters = parameters else { return }
    
                    parameters.updateMode = .noUpdates
    
                    let documentDirectory = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first!
                    let formattedDate = ISO8601DateFormatter().string(from: Date())
    
                    let downloadDirectory = documentDirectory.appendingPathComponent(formattedDate)
    
                    self.generateJob = self.offlineMapTask.generateOfflineMapJob(with: parameters, downloadDirectory: downloadDirectory)
    
                    let numberFormatter = NumberFormatter()
                    numberFormatter.numberStyle = .percent
    
                    self.observation = self.generateJob.progress.observe(\.fractionCompleted) { (progress, _) in
                            print("Percentage Completed: \(numberFormatter.string(from: NSNumber(value: progress.fractionCompleted)))")
                        }
    
                    var i = 0
                    self.generateJob.start(statusHandler: { (_) in
                        // Print Job messages to console.
                        while i < self.generateJob.messages.count {
                            print("Job message \(i): \(self.generateJob.messages[i].message)")
                            i += 1
                        }
                    })
    
                    { [weak self] (result, error) in
                        guard let self = self else { return }
                        if let error = error {
                            print("Error downloading the offline map: \(error)")
                            return
                        }
                        guard let result = result else { return }
                        self.mapView.map = result.offlineMap
    
                    }
    
                })
    
        }
    
        override func viewDidLoad() {
            super.viewDidLoad()
            //AGSArcGISRuntimeEnvironment.apiKey = "YOUR-API-KEY"
            setupMap()
        }
    }
    
  3. Press <Command+R> to run the app.

    If you are using the Xcode simulator your system must meet these minimum requirements: macOS Catalina, Xcode 11, iOS 13. If you are using a physical device, then refer to the system requirements.

You should see a red rectangle on the stormwater network within Naperville, IL, USA. This is the area of the web map that you will take offline.

Dowload and display the offline map

You can generate and download an offline map for your area of interest using the AGSGenerateOfflineMapJob class. When complete, the job will provide an offline map on your device that you can display in a map view.

  1. Define two instance variables for AGSOfflineMapTask and AGSGenerateOfflineMapJob.

    Instance variables ensure that objects are not deallocated while asynchronous methods are executing. If an object is deallocated while one of its asynchronous method is executing, the completion callback closure will never be called.

    ViewController.swift
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    // Copyright 2021 Esri.
    //
    // Licensed under the Apache License, Version 2.0 (the "License");
    // you may not use this file except in compliance with the License.
    // You may obtain a copy of the License at
    //
    //   https://www.apache.org/licenses/LICENSE-2.0
    //
    // Unless required by applicable law or agreed to in writing, software
    // distributed under the License is distributed on an "AS IS" BASIS,
    // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    // See the License for the specific language governing permissions and
    // limitations under the License.
    
    import UIKit
    import ArcGIS
    
    
    class ViewController: UIViewController, AGSGeoViewTouchDelegate {
        @IBOutlet weak var mapView: AGSMapView!
    
        var offlineMapTask: AGSOfflineMapTask!
        var generateJob: AGSGenerateOfflineMapJob!
    
        var observation: NSKeyValueObservation?
    
        private func setupMap() {
            let portal = AGSPortal.arcGISOnline(withLoginRequired: false)
    
            let itemID = "acc027394bc84c2fb04d1ed317aac674"
    
            let portalItem = AGSPortalItem(portal: portal, itemID: itemID)
            let map = AGSMap(item: portalItem)
    
            mapView.map = map
    
            let offlineArea = AGSEnvelope(xMin: -88.1535, yMin: 41.7695, xMax: -88.1490, yMax: 41.7725, spatialReference: .wgs84())
    
            let simpleLineSymbol = AGSSimpleLineSymbol(style: .solid, color: .red,
                width: 3)
            let simpleFillSymbol = AGSSimpleFillSymbol(
                style: .solid,
                color: .clear,
                outline: simpleLineSymbol)
            let graphic = AGSGraphic(geometry: offlineArea, symbol: simpleFillSymbol, attributes: nil)
    
            let graphicOverlay = AGSGraphicsOverlay()
            self.mapView.graphicsOverlays.add(graphicOverlay)
    
            graphicOverlay.graphics.add(graphic)
    
            offlineMapTask = AGSOfflineMapTask(onlineMap: map)
    
            offlineMapTask.defaultGenerateOfflineMapParameters(withAreaOfInterest: offlineArea, completion: {[weak self] (parameters, error) in
                guard let self = self else { return }
                if let error = error {
                    print("Error fetching default parameters for the area of interest : \(error.localizedDescription)")
                        return
                    }
                    guard let parameters = parameters else { return }
    
                    parameters.updateMode = .noUpdates
    
                    let documentDirectory = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first!
                    let formattedDate = ISO8601DateFormatter().string(from: Date())
    
                    let downloadDirectory = documentDirectory.appendingPathComponent(formattedDate)
    
                    self.generateJob = self.offlineMapTask.generateOfflineMapJob(with: parameters, downloadDirectory: downloadDirectory)
    
                    let numberFormatter = NumberFormatter()
                    numberFormatter.numberStyle = .percent
    
                    self.observation = self.generateJob.progress.observe(\.fractionCompleted) { (progress, _) in
                            print("Percentage Completed: \(numberFormatter.string(from: NSNumber(value: progress.fractionCompleted)))")
                        }
    
                    var i = 0
                    self.generateJob.start(statusHandler: { (_) in
                        // Print Job messages to console.
                        while i < self.generateJob.messages.count {
                            print("Job message \(i): \(self.generateJob.messages[i].message)")
                            i += 1
                        }
                    })
    
                    { [weak self] (result, error) in
                        guard let self = self else { return }
                        if let error = error {
                            print("Error downloading the offline map: \(error)")
                            return
                        }
                        guard let result = result else { return }
                        self.mapView.map = result.offlineMap
    
                    }
    
                })
    
        }
    
        override func viewDidLoad() {
            super.viewDidLoad()
            //AGSArcGISRuntimeEnvironment.apiKey = "YOUR-API-KEY"
            setupMap()
        }
    }
    
  2. Modify the setupMap() function to set the offlineMapTask instance variable to a new AGSOfflineMapTask referencing the online map.

    ViewController.swift
    Add line.
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    // Copyright 2021 Esri.
    //
    // Licensed under the Apache License, Version 2.0 (the "License");
    // you may not use this file except in compliance with the License.
    // You may obtain a copy of the License at
    //
    //   https://www.apache.org/licenses/LICENSE-2.0
    //
    // Unless required by applicable law or agreed to in writing, software
    // distributed under the License is distributed on an "AS IS" BASIS,
    // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    // See the License for the specific language governing permissions and
    // limitations under the License.
    
    import UIKit
    import ArcGIS
    
    
    class ViewController: UIViewController, AGSGeoViewTouchDelegate {
        @IBOutlet weak var mapView: AGSMapView!
    
        var offlineMapTask: AGSOfflineMapTask!
        var generateJob: AGSGenerateOfflineMapJob!
    
        var observation: NSKeyValueObservation?
    
        private func setupMap() {
            let portal = AGSPortal.arcGISOnline(withLoginRequired: false)
    
            let itemID = "acc027394bc84c2fb04d1ed317aac674"
    
            let portalItem = AGSPortalItem(portal: portal, itemID: itemID)
            let map = AGSMap(item: portalItem)
    
            mapView.map = map
    
            let offlineArea = AGSEnvelope(xMin: -88.1535, yMin: 41.7695, xMax: -88.1490, yMax: 41.7725, spatialReference: .wgs84())
    
            let simpleLineSymbol = AGSSimpleLineSymbol(style: .solid, color: .red,
                width: 3)
            let simpleFillSymbol = AGSSimpleFillSymbol(
                style: .solid,
                color: .clear,
                outline: simpleLineSymbol)
            let graphic = AGSGraphic(geometry: offlineArea, symbol: simpleFillSymbol, attributes: nil)
    
            let graphicOverlay = AGSGraphicsOverlay()
            self.mapView.graphicsOverlays.add(graphicOverlay)
    
            graphicOverlay.graphics.add(graphic)
    
            offlineMapTask = AGSOfflineMapTask(onlineMap: map)
    
            offlineMapTask.defaultGenerateOfflineMapParameters(withAreaOfInterest: offlineArea, completion: {[weak self] (parameters, error) in
                guard let self = self else { return }
                if let error = error {
                    print("Error fetching default parameters for the area of interest : \(error.localizedDescription)")
                        return
                    }
                    guard let parameters = parameters else { return }
    
                    parameters.updateMode = .noUpdates
    
                    let documentDirectory = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first!
                    let formattedDate = ISO8601DateFormatter().string(from: Date())
    
                    let downloadDirectory = documentDirectory.appendingPathComponent(formattedDate)
    
                    self.generateJob = self.offlineMapTask.generateOfflineMapJob(with: parameters, downloadDirectory: downloadDirectory)
    
                    let numberFormatter = NumberFormatter()
                    numberFormatter.numberStyle = .percent
    
                    self.observation = self.generateJob.progress.observe(\.fractionCompleted) { (progress, _) in
                            print("Percentage Completed: \(numberFormatter.string(from: NSNumber(value: progress.fractionCompleted)))")
                        }
    
                    var i = 0
                    self.generateJob.start(statusHandler: { (_) in
                        // Print Job messages to console.
                        while i < self.generateJob.messages.count {
                            print("Job message \(i): \(self.generateJob.messages[i].message)")
                            i += 1
                        }
                    })
    
                    { [weak self] (result, error) in
                        guard let self = self else { return }
                        if let error = error {
                            print("Error downloading the offline map: \(error)")
                            return
                        }
                        guard let result = result else { return }
                        self.mapView.map = result.offlineMap
    
                    }
    
                })
    
        }
    
        override func viewDidLoad() {
            super.viewDidLoad()
            //AGSArcGISRuntimeEnvironment.apiKey = "YOUR-API-KEY"
            setupMap()
        }
    }
    
  3. Get a default set of AGSGenerateOfflineMapParameters that you can use to generate and download the offline map.

    Pass the offlineArea to the defaultGenerateOfflineMapParameters() method on the offlineMapTask. Upon completion, obtain the parameters and set the updateMode to .noUpdates. This will ensure that the offline map is read-only.

    This tutorial does not involve editing and updating the contents of the offline map. When an offline map is editable, metadata is stored in ArcGIS to track and synchronize edits. If you set the updateMode to .noUpdates this avoids the overhead of maintaining this metadata in ArcGIS.

    ViewController.swift
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    // Copyright 2021 Esri.
    //
    // Licensed under the Apache License, Version 2.0 (the "License");
    // you may not use this file except in compliance with the License.
    // You may obtain a copy of the License at
    //
    //   https://www.apache.org/licenses/LICENSE-2.0
    //
    // Unless required by applicable law or agreed to in writing, software
    // distributed under the License is distributed on an "AS IS" BASIS,
    // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    // See the License for the specific language governing permissions and
    // limitations under the License.
    
    import UIKit
    import ArcGIS
    
    
    class ViewController: UIViewController, AGSGeoViewTouchDelegate {
        @IBOutlet weak var mapView: AGSMapView!
    
        var offlineMapTask: AGSOfflineMapTask!
        var generateJob: AGSGenerateOfflineMapJob!
    
        var observation: NSKeyValueObservation?
    
        private func setupMap() {
            let portal = AGSPortal.arcGISOnline(withLoginRequired: false)
    
            let itemID = "acc027394bc84c2fb04d1ed317aac674"
    
            let portalItem = AGSPortalItem(portal: portal, itemID: itemID)
            let map = AGSMap(item: portalItem)
    
            mapView.map = map
    
            let offlineArea = AGSEnvelope(xMin: -88.1535, yMin: 41.7695, xMax: -88.1490, yMax: 41.7725, spatialReference: .wgs84())
    
            let simpleLineSymbol = AGSSimpleLineSymbol(style: .solid, color: .red,
                width: 3)
            let simpleFillSymbol = AGSSimpleFillSymbol(
                style: .solid,
                color: .clear,
                outline: simpleLineSymbol)
            let graphic = AGSGraphic(geometry: offlineArea, symbol: simpleFillSymbol, attributes: nil)
    
            let graphicOverlay = AGSGraphicsOverlay()
            self.mapView.graphicsOverlays.add(graphicOverlay)
    
            graphicOverlay.graphics.add(graphic)
    
            offlineMapTask = AGSOfflineMapTask(onlineMap: map)
    
            offlineMapTask.defaultGenerateOfflineMapParameters(withAreaOfInterest: offlineArea, completion: {[weak self] (parameters, error) in
                guard let self = self else { return }
                if let error = error {
                    print("Error fetching default parameters for the area of interest : \(error.localizedDescription)")
                        return
                    }
                    guard let parameters = parameters else { return }
    
                    parameters.updateMode = .noUpdates
    
                    let documentDirectory = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first!
                    let formattedDate = ISO8601DateFormatter().string(from: Date())
    
                    let downloadDirectory = documentDirectory.appendingPathComponent(formattedDate)
    
                    self.generateJob = self.offlineMapTask.generateOfflineMapJob(with: parameters, downloadDirectory: downloadDirectory)
    
                    let numberFormatter = NumberFormatter()
                    numberFormatter.numberStyle = .percent
    
                    self.observation = self.generateJob.progress.observe(\.fractionCompleted) { (progress, _) in
                            print("Percentage Completed: \(numberFormatter.string(from: NSNumber(value: progress.fractionCompleted)))")
                        }
    
                    var i = 0
                    self.generateJob.start(statusHandler: { (_) in
                        // Print Job messages to console.
                        while i < self.generateJob.messages.count {
                            print("Job message \(i): \(self.generateJob.messages[i].message)")
                            i += 1
                        }
                    })
    
                    { [weak self] (result, error) in
                        guard let self = self else { return }
                        if let error = error {
                            print("Error downloading the offline map: \(error)")
                            return
                        }
                        guard let result = result else { return }
                        self.mapView.map = result.offlineMap
    
                    }
    
                })
    
        }
    
        override func viewDidLoad() {
            super.viewDidLoad()
            //AGSArcGISRuntimeEnvironment.apiKey = "YOUR-API-KEY"
            setupMap()
        }
    }
    
  4. Set a download directory for the offline map.

    ViewController.swift
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    // Copyright 2021 Esri.
    //
    // Licensed under the Apache License, Version 2.0 (the "License");
    // you may not use this file except in compliance with the License.
    // You may obtain a copy of the License at
    //
    //   https://www.apache.org/licenses/LICENSE-2.0
    //
    // Unless required by applicable law or agreed to in writing, software
    // distributed under the License is distributed on an "AS IS" BASIS,
    // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    // See the License for the specific language governing permissions and
    // limitations under the License.
    
    import UIKit
    import ArcGIS
    
    
    class ViewController: UIViewController, AGSGeoViewTouchDelegate {
        @IBOutlet weak var mapView: AGSMapView!
    
        var offlineMapTask: AGSOfflineMapTask!
        var generateJob: AGSGenerateOfflineMapJob!
    
        var observation: NSKeyValueObservation?
    
        private func setupMap() {
            let portal = AGSPortal.arcGISOnline(withLoginRequired: false)
    
            let itemID = "acc027394bc84c2fb04d1ed317aac674"
    
            let portalItem = AGSPortalItem(portal: portal, itemID: itemID)
            let map = AGSMap(item: portalItem)
    
            mapView.map = map
    
            let offlineArea = AGSEnvelope(xMin: -88.1535, yMin: 41.7695, xMax: -88.1490, yMax: 41.7725, spatialReference: .wgs84())
    
            let simpleLineSymbol = AGSSimpleLineSymbol(style: .solid, color: .red,
                width: 3)
            let simpleFillSymbol = AGSSimpleFillSymbol(
                style: .solid,
                color: .clear,
                outline: simpleLineSymbol)
            let graphic = AGSGraphic(geometry: offlineArea, symbol: simpleFillSymbol, attributes: nil)
    
            let graphicOverlay = AGSGraphicsOverlay()
            self.mapView.graphicsOverlays.add(graphicOverlay)
    
            graphicOverlay.graphics.add(graphic)
    
            offlineMapTask = AGSOfflineMapTask(onlineMap: map)
    
            offlineMapTask.defaultGenerateOfflineMapParameters(withAreaOfInterest: offlineArea, completion: {[weak self] (parameters, error) in
                guard let self = self else { return }
                if let error = error {
                    print("Error fetching default parameters for the area of interest : \(error.localizedDescription)")
                        return
                    }
                    guard let parameters = parameters else { return }
    
                    parameters.updateMode = .noUpdates
    
                    let documentDirectory = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first!
                    let formattedDate = ISO8601DateFormatter().string(from: Date())
    
                    let downloadDirectory = documentDirectory.appendingPathComponent(formattedDate)
    
                    self.generateJob = self.offlineMapTask.generateOfflineMapJob(with: parameters, downloadDirectory: downloadDirectory)
    
                    let numberFormatter = NumberFormatter()
                    numberFormatter.numberStyle = .percent
    
                    self.observation = self.generateJob.progress.observe(\.fractionCompleted) { (progress, _) in
                            print("Percentage Completed: \(numberFormatter.string(from: NSNumber(value: progress.fractionCompleted)))")
                        }
    
                    var i = 0
                    self.generateJob.start(statusHandler: { (_) in
                        // Print Job messages to console.
                        while i < self.generateJob.messages.count {
                            print("Job message \(i): \(self.generateJob.messages[i].message)")
                            i += 1
                        }
                    })
    
                    { [weak self] (result, error) in
                        guard let self = self else { return }
                        if let error = error {
                            print("Error downloading the offline map: \(error)")
                            return
                        }
                        guard let result = result else { return }
                        self.mapView.map = result.offlineMap
    
                    }
    
                })
    
        }
    
        override func viewDidLoad() {
            super.viewDidLoad()
            //AGSArcGISRuntimeEnvironment.apiKey = "YOUR-API-KEY"
            setupMap()
        }
    }
    

    This tutorial code creates a new, unique folder in the device's documents folder using the current date and time.

  5. Set the generateJob instance variable to a new AGSGenerateOfflineMapJob using the parameters and the downloadDirectory.

    ViewController.swift
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    // Copyright 2021 Esri.
    //
    // Licensed under the Apache License, Version 2.0 (the "License");
    // you may not use this file except in compliance with the License.
    // You may obtain a copy of the License at
    //
    //   https://www.apache.org/licenses/LICENSE-2.0
    //
    // Unless required by applicable law or agreed to in writing, software
    // distributed under the License is distributed on an "AS IS" BASIS,
    // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    // See the License for the specific language governing permissions and
    // limitations under the License.
    
    import UIKit
    import ArcGIS
    
    
    class ViewController: UIViewController, AGSGeoViewTouchDelegate {
        @IBOutlet weak var mapView: AGSMapView!
    
        var offlineMapTask: AGSOfflineMapTask!
        var generateJob: AGSGenerateOfflineMapJob!
    
        var observation: NSKeyValueObservation?
    
        private func setupMap() {
            let portal = AGSPortal.arcGISOnline(withLoginRequired: false)
    
            let itemID = "acc027394bc84c2fb04d1ed317aac674"
    
            let portalItem = AGSPortalItem(portal: portal, itemID: itemID)
            let map = AGSMap(item: portalItem)
    
            mapView.map = map
    
            let offlineArea = AGSEnvelope(xMin: -88.1535, yMin: 41.7695, xMax: -88.1490, yMax: 41.7725, spatialReference: .wgs84())
    
            let simpleLineSymbol = AGSSimpleLineSymbol(style: .solid, color: .red,
                width: 3)
            let simpleFillSymbol = AGSSimpleFillSymbol(
                style: .solid,
                color: .clear,
                outline: simpleLineSymbol)
            let graphic = AGSGraphic(geometry: offlineArea, symbol: simpleFillSymbol, attributes: nil)
    
            let graphicOverlay = AGSGraphicsOverlay()
            self.mapView.graphicsOverlays.add(graphicOverlay)
    
            graphicOverlay.graphics.add(graphic)
    
            offlineMapTask = AGSOfflineMapTask(onlineMap: map)
    
            offlineMapTask.defaultGenerateOfflineMapParameters(withAreaOfInterest: offlineArea, completion: {[weak self] (parameters, error) in
                guard let self = self else { return }
                if let error = error {
                    print("Error fetching default parameters for the area of interest : \(error.localizedDescription)")
                        return
                    }
                    guard let parameters = parameters else { return }
    
                    parameters.updateMode = .noUpdates
    
                    let documentDirectory = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first!
                    let formattedDate = ISO8601DateFormatter().string(from: Date())
    
                    let downloadDirectory = documentDirectory.appendingPathComponent(formattedDate)
    
                    self.generateJob = self.offlineMapTask.generateOfflineMapJob(with: parameters, downloadDirectory: downloadDirectory)
    
                    let numberFormatter = NumberFormatter()
                    numberFormatter.numberStyle = .percent
    
                    self.observation = self.generateJob.progress.observe(\.fractionCompleted) { (progress, _) in
                            print("Percentage Completed: \(numberFormatter.string(from: NSNumber(value: progress.fractionCompleted)))")
                        }
    
                    var i = 0
                    self.generateJob.start(statusHandler: { (_) in
                        // Print Job messages to console.
                        while i < self.generateJob.messages.count {
                            print("Job message \(i): \(self.generateJob.messages[i].message)")
                            i += 1
                        }
                    })
    
                    { [weak self] (result, error) in
                        guard let self = self else { return }
                        if let error = error {
                            print("Error downloading the offline map: \(error)")
                            return
                        }
                        guard let result = result else { return }
                        self.mapView.map = result.offlineMap
    
                    }
    
                })
    
        }
    
        override func viewDidLoad() {
            super.viewDidLoad()
            //AGSArcGISRuntimeEnvironment.apiKey = "YOUR-API-KEY"
            setupMap()
        }
    }
    
  6. To view the progress of this asynchronous job, print the fraction of the overall work completed to the Xcode console. Define an instance variable of NSKeyValueObservation to manage the job's progress observations.

    ViewController.swift
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    // Copyright 2021 Esri.
    //
    // Licensed under the Apache License, Version 2.0 (the "License");
    // you may not use this file except in compliance with the License.
    // You may obtain a copy of the License at
    //
    //   https://www.apache.org/licenses/LICENSE-2.0
    //
    // Unless required by applicable law or agreed to in writing, software
    // distributed under the License is distributed on an "AS IS" BASIS,
    // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    // See the License for the specific language governing permissions and
    // limitations under the License.
    
    import UIKit
    import ArcGIS
    
    
    class ViewController: UIViewController, AGSGeoViewTouchDelegate {
        @IBOutlet weak var mapView: AGSMapView!
    
        var offlineMapTask: AGSOfflineMapTask!
        var generateJob: AGSGenerateOfflineMapJob!
    
        var observation: NSKeyValueObservation?
    
        private func setupMap() {
            let portal = AGSPortal.arcGISOnline(withLoginRequired: false)
    
            let itemID = "acc027394bc84c2fb04d1ed317aac674"
    
            let portalItem = AGSPortalItem(portal: portal, itemID: itemID)
            let map = AGSMap(item: portalItem)
    
            mapView.map = map
    
            let offlineArea = AGSEnvelope(xMin: -88.1535, yMin: 41.7695, xMax: -88.1490, yMax: 41.7725, spatialReference: .wgs84())
    
            let simpleLineSymbol = AGSSimpleLineSymbol(style: .solid, color: .red,
                width: 3)
            let simpleFillSymbol = AGSSimpleFillSymbol(
                style: .solid,
                color: .clear,
                outline: simpleLineSymbol)
            let graphic = AGSGraphic(geometry: offlineArea, symbol: simpleFillSymbol, attributes: nil)
    
            let graphicOverlay = AGSGraphicsOverlay()
            self.mapView.graphicsOverlays.add(graphicOverlay)
    
            graphicOverlay.graphics.add(graphic)
    
            offlineMapTask = AGSOfflineMapTask(onlineMap: map)
    
            offlineMapTask.defaultGenerateOfflineMapParameters(withAreaOfInterest: offlineArea, completion: {[weak self] (parameters, error) in
                guard let self = self else { return }
                if let error = error {
                    print("Error fetching default parameters for the area of interest : \(error.localizedDescription)")
                        return
                    }
                    guard let parameters = parameters else { return }
    
                    parameters.updateMode = .noUpdates
    
                    let documentDirectory = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first!
                    let formattedDate = ISO8601DateFormatter().string(from: Date())
    
                    let downloadDirectory = documentDirectory.appendingPathComponent(formattedDate)
    
                    self.generateJob = self.offlineMapTask.generateOfflineMapJob(with: parameters, downloadDirectory: downloadDirectory)
    
                    let numberFormatter = NumberFormatter()
                    numberFormatter.numberStyle = .percent
    
                    self.observation = self.generateJob.progress.observe(\.fractionCompleted) { (progress, _) in
                            print("Percentage Completed: \(numberFormatter.string(from: NSNumber(value: progress.fractionCompleted)))")
                        }
    
                    var i = 0
                    self.generateJob.start(statusHandler: { (_) in
                        // Print Job messages to console.
                        while i < self.generateJob.messages.count {
                            print("Job message \(i): \(self.generateJob.messages[i].message)")
                            i += 1
                        }
                    })
    
                    { [weak self] (result, error) in
                        guard let self = self else { return }
                        if let error = error {
                            print("Error downloading the offline map: \(error)")
                            return
                        }
                        guard let result = result else { return }
                        self.mapView.map = result.offlineMap
    
                    }
    
                })
    
        }
    
        override func viewDidLoad() {
            super.viewDidLoad()
            //AGSArcGISRuntimeEnvironment.apiKey = "YOUR-API-KEY"
            setupMap()
        }
    }
    

    Observe the fractionCompleted property of the job's progress and print it to the Xcode console in the closure callback. Assign this to the observation instance variable.

    ViewController.swift
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    // Copyright 2021 Esri.
    //
    // Licensed under the Apache License, Version 2.0 (the "License");
    // you may not use this file except in compliance with the License.
    // You may obtain a copy of the License at
    //
    //   https://www.apache.org/licenses/LICENSE-2.0
    //
    // Unless required by applicable law or agreed to in writing, software
    // distributed under the License is distributed on an "AS IS" BASIS,
    // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    // See the License for the specific language governing permissions and
    // limitations under the License.
    
    import UIKit
    import ArcGIS
    
    
    class ViewController: UIViewController, AGSGeoViewTouchDelegate {
        @IBOutlet weak var mapView: AGSMapView!
    
        var offlineMapTask: AGSOfflineMapTask!
        var generateJob: AGSGenerateOfflineMapJob!
    
        var observation: NSKeyValueObservation?
    
        private func setupMap() {
            let portal = AGSPortal.arcGISOnline(withLoginRequired: false)
    
            let itemID = "acc027394bc84c2fb04d1ed317aac674"
    
            let portalItem = AGSPortalItem(portal: portal, itemID: itemID)
            let map = AGSMap(item: portalItem)
    
            mapView.map = map
    
            let offlineArea = AGSEnvelope(xMin: -88.1535, yMin: 41.7695, xMax: -88.1490, yMax: 41.7725, spatialReference: .wgs84())
    
            let simpleLineSymbol = AGSSimpleLineSymbol(style: .solid, color: .red,
                width: 3)
            let simpleFillSymbol = AGSSimpleFillSymbol(
                style: .solid,
                color: .clear,
                outline: simpleLineSymbol)
            let graphic = AGSGraphic(geometry: offlineArea, symbol: simpleFillSymbol, attributes: nil)
    
            let graphicOverlay = AGSGraphicsOverlay()
            self.mapView.graphicsOverlays.add(graphicOverlay)
    
            graphicOverlay.graphics.add(graphic)
    
            offlineMapTask = AGSOfflineMapTask(onlineMap: map)
    
            offlineMapTask.defaultGenerateOfflineMapParameters(withAreaOfInterest: offlineArea, completion: {[weak self] (parameters, error) in
                guard let self = self else { return }
                if let error = error {
                    print("Error fetching default parameters for the area of interest : \(error.localizedDescription)")
                        return
                    }
                    guard let parameters = parameters else { return }
    
                    parameters.updateMode = .noUpdates
    
                    let documentDirectory = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first!
                    let formattedDate = ISO8601DateFormatter().string(from: Date())
    
                    let downloadDirectory = documentDirectory.appendingPathComponent(formattedDate)
    
                    self.generateJob = self.offlineMapTask.generateOfflineMapJob(with: parameters, downloadDirectory: downloadDirectory)
    
                    let numberFormatter = NumberFormatter()
                    numberFormatter.numberStyle = .percent
    
                    self.observation = self.generateJob.progress.observe(\.fractionCompleted) { (progress, _) in
                            print("Percentage Completed: \(numberFormatter.string(from: NSNumber(value: progress.fractionCompleted)))")
                        }
    
                    var i = 0
                    self.generateJob.start(statusHandler: { (_) in
                        // Print Job messages to console.
                        while i < self.generateJob.messages.count {
                            print("Job message \(i): \(self.generateJob.messages[i].message)")
                            i += 1
                        }
                    })
    
                    { [weak self] (result, error) in
                        guard let self = self else { return }
                        if let error = error {
                            print("Error downloading the offline map: \(error)")
                            return
                        }
                        guard let result = result else { return }
                        self.mapView.map = result.offlineMap
    
                    }
    
                })
    
        }
    
        override func viewDidLoad() {
            super.viewDidLoad()
            //AGSArcGISRuntimeEnvironment.apiKey = "YOUR-API-KEY"
            setupMap()
        }
    }
    
  7. Start the job by calling the Start() method. Use the job's status handler to display the work undertaken by this remote job.

    ViewController.swift
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    // Copyright 2021 Esri.
    //
    // Licensed under the Apache License, Version 2.0 (the "License");
    // you may not use this file except in compliance with the License.
    // You may obtain a copy of the License at
    //
    //   https://www.apache.org/licenses/LICENSE-2.0
    //
    // Unless required by applicable law or agreed to in writing, software
    // distributed under the License is distributed on an "AS IS" BASIS,
    // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    // See the License for the specific language governing permissions and
    // limitations under the License.
    
    import UIKit
    import ArcGIS
    
    
    class ViewController: UIViewController, AGSGeoViewTouchDelegate {
        @IBOutlet weak var mapView: AGSMapView!
    
        var offlineMapTask: AGSOfflineMapTask!
        var generateJob: AGSGenerateOfflineMapJob!
    
        var observation: NSKeyValueObservation?
    
        private func setupMap() {
            let portal = AGSPortal.arcGISOnline(withLoginRequired: false)
    
            let itemID = "acc027394bc84c2fb04d1ed317aac674"
    
            let portalItem = AGSPortalItem(portal: portal, itemID: itemID)
            let map = AGSMap(item: portalItem)
    
            mapView.map = map
    
            let offlineArea = AGSEnvelope(xMin: -88.1535, yMin: 41.7695, xMax: -88.1490, yMax: 41.7725, spatialReference: .wgs84())
    
            let simpleLineSymbol = AGSSimpleLineSymbol(style: .solid, color: .red,
                width: 3)
            let simpleFillSymbol = AGSSimpleFillSymbol(
                style: .solid,
                color: .clear,
                outline: simpleLineSymbol)
            let graphic = AGSGraphic(geometry: offlineArea, symbol: simpleFillSymbol, attributes: nil)
    
            let graphicOverlay = AGSGraphicsOverlay()
            self.mapView.graphicsOverlays.add(graphicOverlay)
    
            graphicOverlay.graphics.add(graphic)
    
            offlineMapTask = AGSOfflineMapTask(onlineMap: map)
    
            offlineMapTask.defaultGenerateOfflineMapParameters(withAreaOfInterest: offlineArea, completion: {[weak self] (parameters, error) in
                guard let self = self else { return }
                if let error = error {
                    print("Error fetching default parameters for the area of interest : \(error.localizedDescription)")
                        return
                    }
                    guard let parameters = parameters else { return }
    
                    parameters.updateMode = .noUpdates
    
                    let documentDirectory = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first!
                    let formattedDate = ISO8601DateFormatter().string(from: Date())
    
                    let downloadDirectory = documentDirectory.appendingPathComponent(formattedDate)
    
                    self.generateJob = self.offlineMapTask.generateOfflineMapJob(with: parameters, downloadDirectory: downloadDirectory)
    
                    let numberFormatter = NumberFormatter()
                    numberFormatter.numberStyle = .percent
    
                    self.observation = self.generateJob.progress.observe(\.fractionCompleted) { (progress, _) in
                            print("Percentage Completed: \(numberFormatter.string(from: NSNumber(value: progress.fractionCompleted)))")
                        }
    
                    var i = 0
                    self.generateJob.start(statusHandler: { (_) in
                        // Print Job messages to console.
                        while i < self.generateJob.messages.count {
                            print("Job message \(i): \(self.generateJob.messages[i].message)")
                            i += 1
                        }
                    })
    
                    { [weak self] (result, error) in
                        guard let self = self else { return }
                        if let error = error {
                            print("Error downloading the offline map: \(error)")
                            return
                        }
                        guard let result = result else { return }
                        self.mapView.map = result.offlineMap
    
                    }
    
                })
    
        }
    
        override func viewDidLoad() {
            super.viewDidLoad()
            //AGSArcGISRuntimeEnvironment.apiKey = "YOUR-API-KEY"
            setupMap()
        }
    }
    
  8. When the job completes, retrieve the AGSGenerateOfflineMapResult property. Display the offline map by passing the result.offlineMap property to the AGSMapView.map.

    ViewController.swift
    Add line.Add line.Add line.Add line.Add line.Add line.Add line.Add line.
    77 77 77 77 77 77 77 77 77 77 77 77 77 77 77 77 77 77 77 77 77 77 77 77 77 77 77 77 77 77 77 77 77 77 77 77 77 77 77 77 77 77 77 77 77 77 77 77 77 77 77 77 77 77 77 77 77 77 77 77 77 77 77 77 77 77 77 77 77 77 77 77 77 77 77 77 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 96 96 96 96 96 96 96 96 96 96 96
    // Copyright 2021 Esri.
    //
    // Licensed under the Apache License, Version 2.0 (the "License");
    // you may not use this file except in compliance with the License.
    // You may obtain a copy of the License at
    //
    //   https://www.apache.org/licenses/LICENSE-2.0
    //
    // Unless required by applicable law or agreed to in writing, software
    // distributed under the License is distributed on an "AS IS" BASIS,
    // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    // See the License for the specific language governing permissions and
    // limitations under the License.
    
    import UIKit
    import ArcGIS
    
    
    class ViewController: UIViewController, AGSGeoViewTouchDelegate {
        @IBOutlet weak var mapView: AGSMapView!
    
        var offlineMapTask: AGSOfflineMapTask!
        var generateJob: AGSGenerateOfflineMapJob!
    
        var observation: NSKeyValueObservation?
    
        private func setupMap() {
            let portal = AGSPortal.arcGISOnline(withLoginRequired: false)
    
            let itemID = "acc027394bc84c2fb04d1ed317aac674"
    
            let portalItem = AGSPortalItem(portal: portal, itemID: itemID)
            let map = AGSMap(item: portalItem)
    
            mapView.map = map
    
            let offlineArea = AGSEnvelope(xMin: -88.1535, yMin: 41.7695, xMax: -88.1490, yMax: 41.7725, spatialReference: .wgs84())
    
            let simpleLineSymbol = AGSSimpleLineSymbol(style: .solid, color: .red,
                width: 3)
            let simpleFillSymbol = AGSSimpleFillSymbol(
                style: .solid,
                color: .clear,
                outline: simpleLineSymbol)
            let graphic = AGSGraphic(geometry: offlineArea, symbol: simpleFillSymbol, attributes: nil)
    
            let graphicOverlay = AGSGraphicsOverlay()
            self.mapView.graphicsOverlays.add(graphicOverlay)
    
            graphicOverlay.graphics.add(graphic)
    
            offlineMapTask = AGSOfflineMapTask(onlineMap: map)
    
            offlineMapTask.defaultGenerateOfflineMapParameters(withAreaOfInterest: offlineArea, completion: {[weak self] (parameters, error) in
                guard let self = self else { return }
                if let error = error {
                    print("Error fetching default parameters for the area of interest : \(error.localizedDescription)")
                        return
                    }
                    guard let parameters = parameters else { return }
    
                    parameters.updateMode = .noUpdates
    
                    let documentDirectory = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first!
                    let formattedDate = ISO8601DateFormatter().string(from: Date())
    
                    let downloadDirectory = documentDirectory.appendingPathComponent(formattedDate)
    
                    self.generateJob = self.offlineMapTask.generateOfflineMapJob(with: parameters, downloadDirectory: downloadDirectory)
    
                    let numberFormatter = NumberFormatter()
                    numberFormatter.numberStyle = .percent
    
                    self.observation = self.generateJob.progress.observe(\.fractionCompleted) { (progress, _) in
                            print("Percentage Completed: \(numberFormatter.string(from: NSNumber(value: progress.fractionCompleted)))")
                        }
    
                    var i = 0
                    self.generateJob.start(statusHandler: { (_) in
                        // Print Job messages to console.
                        while i < self.generateJob.messages.count {
                            print("Job message \(i): \(self.generateJob.messages[i].message)")
                            i += 1
                        }
                    })
    
                    { [weak self] (result, error) in
                        guard let self = self else { return }
                        if let error = error {
                            print("Error downloading the offline map: \(error)")
                            return
                        }
                        guard let result = result else { return }
                        self.mapView.map = result.offlineMap
    
                    }
    
                })
    
        }
    
        override func viewDidLoad() {
            super.viewDidLoad()
            //AGSArcGISRuntimeEnvironment.apiKey = "YOUR-API-KEY"
            setupMap()
        }
    }
    
  9. Press <Command+R> to run the app.

    If you are using the Xcode simulator your system must meet these minimum requirements: macOS Catalina, Xcode 11, iOS 13. If you are using a physical device, then refer to the system requirements.

You should see an offline map for the specified area of the Naperville water network. Remove your network connection and you will still be able to pinch, drag, and double-tap the map view to explore this offline map.

What's next?

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