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GenerateOfflineMapJob Class

A Job to generate an offline map from an online map.
Inheritance Hierarchy
SystemObject
  Esri.ArcGISRuntime.TasksJobGenerateOfflineMapResult
    Esri.ArcGISRuntime.Tasks.OfflineGenerateOfflineMapJob

Namespace:  Esri.ArcGISRuntime.Tasks.Offline
Assembly:  Esri.ArcGISRuntime (in Esri.ArcGISRuntime.dll) Version: 100.11.0
Syntax
public sealed class GenerateOfflineMapJob : Job<GenerateOfflineMapResult>

The GenerateOfflineMapJob type exposes the following members.

Properties
  NameDescription
Public propertyCredential
Gets or sets the security credential used to access the web service that provides the job's functionality
(Inherited from JobT.)
Public propertyDownloadDirectoryPath
Gets the download directory used by this job to write the mobile map package result
Public propertyCode exampleError
Gets the error if one occurred during execution of the job. If no error has occurred, then null is returned.
(Inherited from JobT.)
Public propertyCode exampleMessages
Gets the job's status messages
(Inherited from JobT.)
Public propertyOnlineMap
Gets the online Map used by this job.
Public propertyParameterOverrides
Gets the GenerateOfflineMapParameterOverrides used by this job.
Public propertyParameters
Gets the GenerateOfflineMapParameters used by this job.
Public propertyCode exampleProgress
Gets the current progress of the job as a percentage toward completion
(Inherited from JobT.)
Public propertyServerJobId
Gets the server job ID of the job
(Inherited from JobT.)
Public propertyCode exampleStatus
Gets the status of the job
(Inherited from JobT.)
Top
Methods
Events
Examples

UWP

Example Name: GenerateOfflineMap

Take a web map offline.

Code example screen shot.

C#
// Copyright 2018 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: http://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.

using Esri.ArcGISRuntime.Geometry;
using Esri.ArcGISRuntime.Mapping;
using Esri.ArcGISRuntime.Portal;
using Esri.ArcGISRuntime.Security;
using Esri.ArcGISRuntime.Symbology;
using Esri.ArcGISRuntime.Tasks;
using Esri.ArcGISRuntime.Tasks.Offline;
using Esri.ArcGISRuntime.UI;
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Threading.Tasks;
using Windows.UI.Popups;

namespace ArcGISRuntime.UWP.Samples.GenerateOfflineMap
{
    [ArcGISRuntime.Samples.Shared.Attributes.Sample(
        name: "Generate offline map",
        category: "Map",
        description: "Take a web map offline.",
        instructions: "When the app starts, you will be prompted to sign in using a free ArcGIS Online account. Once the map loads, zoom to the extent you want to take offline. The red border shows the extent that will be downloaded. Click the \"Take Map Offline\" button to start the offline map job. The progress bar will show the job's progress. When complete, the offline map will replace the online map in the map view.",
        tags: new[] { "download", "offline", "save", "web map" })]
    public partial class GenerateOfflineMap
    {
        // The job to generate an offline map.
        private GenerateOfflineMapJob _generateOfflineMapJob;

        // The extent of the data to take offline.
        private Envelope _areaOfInterest = new Envelope(-88.1541, 41.7690, -88.1471, 41.7720, SpatialReferences.Wgs84);

        // The ID for a web map item hosted on the server (water network map of Naperville IL).
        private string WebMapId = "acc027394bc84c2fb04d1ed317aac674";

        public GenerateOfflineMap()
        {
            InitializeComponent();

            // Load the web map, show area of interest, restrict map interaction, and set up authorization. 
            Initialize();
        }

        private async void Initialize()
        {
            try
            {
                // Call a function to set up the AuthenticationManager for OAuth.
                SetOAuthInfo();

                // Create the ArcGIS Online portal.
                ArcGISPortal portal = await ArcGISPortal.CreateAsync();

                // Get the Naperville water web map item using its ID.
                PortalItem webmapItem = await PortalItem.CreateAsync(portal, WebMapId);

                // Create a map from the web map item.
                Map onlineMap = new Map(webmapItem);

                // Display the map in the MapView.
                MyMapView.Map = onlineMap;

                // Disable user interactions on the map (no panning or zooming from the initial extent).
                MyMapView.InteractionOptions = new MapViewInteractionOptions
                {
                    IsEnabled = false
                };

                // Create a graphics overlay for the extent graphic and apply a renderer.
                SimpleLineSymbol aoiOutlineSymbol = new SimpleLineSymbol(SimpleLineSymbolStyle.Solid, System.Drawing.Color.Red, 3);
                GraphicsOverlay extentOverlay = new GraphicsOverlay
                {
                    Renderer = new SimpleRenderer(aoiOutlineSymbol)
                };
                MyMapView.GraphicsOverlays.Add(extentOverlay);

                // Add a graphic to show the area of interest (extent) that will be taken offline.
                Graphic aoiGraphic = new Graphic(_areaOfInterest);
                extentOverlay.Graphics.Add(aoiGraphic);

                // Hide the map loading progress indicator.
                loadingIndicator.Visibility = Windows.UI.Xaml.Visibility.Collapsed;

                // When the map view unloads, try to clean up existing output data folders.
                MyMapView.Unloaded += (s, e) =>
                {
                    // Find output mobile map folders in the temp directory.
                    string[] outputFolders = Directory.GetDirectories(Environment.ExpandEnvironmentVariables("%TEMP%"), "NapervilleWaterNetwork*");

                    // Loop through the folder names and delete them.
                    foreach (string dir in outputFolders)
                    {
                        try
                        {
                            // Delete the folder.
                            Directory.Delete(dir, true);
                        }
                        catch (Exception)
                        {
                            // Ignore exceptions (files might be locked, for example).
                        }
                    }
                };
            }
            catch (Exception ex)
            {
                MessageDialog dialog = new MessageDialog(ex.ToString(), "Error loading map");
                await dialog.ShowAsync();
            }
        }

        private async void TakeMapOfflineButton_Click(object sender, Windows.UI.Xaml.RoutedEventArgs e)
        {
            // Create a new folder for the output mobile map.
            string packagePath = Path.Combine(Environment.ExpandEnvironmentVariables("%TEMP%"), @"NapervilleWaterNetwork");
            int num = 1;
            while (Directory.Exists(packagePath))
            {
                packagePath = Path.Combine(Environment.ExpandEnvironmentVariables("%TEMP%"), @"NapervilleWaterNetwork" + num.ToString());
                num++;
            }

            // Create the output directory.
            Directory.CreateDirectory(packagePath);

            try
            {
                // Show the progress indicator while the job is running.
                busyIndicator.Visibility = Windows.UI.Xaml.Visibility.Visible;

                // Create an offline map task with the current (online) map.
                OfflineMapTask takeMapOfflineTask = await OfflineMapTask.CreateAsync(MyMapView.Map);

                // Create the default parameters for the task, pass in the area of interest.
                GenerateOfflineMapParameters parameters = await takeMapOfflineTask.CreateDefaultGenerateOfflineMapParametersAsync(_areaOfInterest);

                // Create the job with the parameters and output location.
                _generateOfflineMapJob = takeMapOfflineTask.GenerateOfflineMap(parameters, packagePath);

                // Handle the progress changed event for the job.
                _generateOfflineMapJob.ProgressChanged += OfflineMapJob_ProgressChanged;

                // Await the job to generate geodatabases, export tile packages, and create the mobile map package.
                GenerateOfflineMapResult results = await _generateOfflineMapJob.GetResultAsync();

                // Check for job failure (writing the output was denied, e.g.).
                if (_generateOfflineMapJob.Status != JobStatus.Succeeded)
                {
                    MessageDialog dialog = new MessageDialog("Generate offline map package failed.", "Job status");
                    await dialog.ShowAsync();
                    busyIndicator.Visibility = Windows.UI.Xaml.Visibility.Collapsed;
                }

                // Check for errors with individual layers.
                if (results.LayerErrors.Any())
                {
                    // Build a string to show all layer errors.
                    System.Text.StringBuilder errorBuilder = new System.Text.StringBuilder();
                    foreach (KeyValuePair<Layer, Exception> layerError in results.LayerErrors)
                    {
                        errorBuilder.AppendLine(string.Format("{0} : {1}", layerError.Key.Id, layerError.Value.Message));
                    }

                    // Show layer errors.
                    string errorText = errorBuilder.ToString();
                    MessageDialog dialog = new MessageDialog(errorText, "Layer errors");
                    await dialog.ShowAsync();
                }

                // Display the offline map.
                MyMapView.Map = results.OfflineMap;

                // Apply the original viewpoint for the offline map.
                MyMapView.SetViewpoint(new Viewpoint(_areaOfInterest));

                // Enable map interaction so the user can explore the offline data.
                MyMapView.InteractionOptions.IsEnabled = true;

                // Hide the "Take map offline" button.
                takeOfflineArea.Visibility = Windows.UI.Xaml.Visibility.Collapsed;

                // Show a message that the map is offline.
                messageArea.Visibility = Windows.UI.Xaml.Visibility.Visible;
            }
            catch (TaskCanceledException)
            {
                // Generate offline map task was canceled.
                MessageDialog dialog = new MessageDialog("Taking map offline was canceled");
                await dialog.ShowAsync();
            }
            catch (Exception ex)
            {
                // Exception while taking the map offline.
                MessageDialog dialog = new MessageDialog(ex.Message, "Offline map error");
                await dialog.ShowAsync();
            }
            finally
            {
                // Hide the activity indicator when the job is done.
                busyIndicator.Visibility = Windows.UI.Xaml.Visibility.Collapsed;
            }
        }

        // Show changes in job progress.
        private async void OfflineMapJob_ProgressChanged(object sender, EventArgs e)
        {
            // Get the job.
            GenerateOfflineMapJob job = sender as GenerateOfflineMapJob;

            // Dispatch to the UI thread.
            await Dispatcher.RunAsync( Windows.UI.Core.CoreDispatcherPriority.Normal, () =>
            {
                // Show the percent complete and update the progress bar.
                Percentage.Text = job.Progress > 0 ? job.Progress.ToString() + " %" : string.Empty;
                progressBar.Value = job.Progress;
            });
        }

        private void CancelJobButton_Click(object sender, Windows.UI.Xaml.RoutedEventArgs e)
        {
            // The user canceled the job.
            _generateOfflineMapJob.Cancel();
        }

        #region Authentication
        // Constants for OAuth-related values.
        // - The URL of the portal to authenticate with (ArcGIS Online).
        private const string ServerUrl = "https://www.arcgis.com/sharing/rest";
        // - The Client ID for an app registered with the server (the ID below is for a public app created by the ArcGIS Runtime team).
        private const string AppClientId = @"lgAdHkYZYlwwfAhC";
        // - An optional client secret for the app (only needed for the OAuthAuthorizationCode authorization type).
        private const string ClientSecret = "";
        // - A URL for redirecting after a successful authorization (this must be a URL configured with the app).
        private const string OAuthRedirectUrl = @"my-ags-app://auth";

        private void SetOAuthInfo()
        {
            // Register the server information with the AuthenticationManager.
            ServerInfo serverInfo = new ServerInfo
            {
                ServerUri = new Uri(ServerUrl),
                TokenAuthenticationType = TokenAuthenticationType.OAuthImplicit,
                OAuthClientInfo = new OAuthClientInfo
                {
                    ClientId = AppClientId,
                    RedirectUri = new Uri(OAuthRedirectUrl)
                }
            };

            // Register this server with AuthenticationManager.
            AuthenticationManager.Current.RegisterServer(serverInfo);

            // Use a function in this class to challenge for credentials.
            AuthenticationManager.Current.ChallengeHandler = new ChallengeHandler(CreateCredentialAsync);

            // Note: In a WPF app, you need to associate a custom IOAuthAuthorizeHandler component with the AuthenticationManager to 
            //     handle showing OAuth login controls (AuthenticationManager.Current.OAuthAuthorizeHandler = new MyOAuthAuthorize();).
            //     The UWP AuthenticationManager, however, uses a built-in IOAuthAuthorizeHandler (based on WebAuthenticationBroker).
        }

        public async Task<Credential> CreateCredentialAsync(CredentialRequestInfo info)
        {
            // ChallengeHandler function for AuthenticationManager that will be called whenever a secured resource is accessed.
            Credential credential = null;

            try
            {
                // AuthenticationManager will handle challenging the user for credentials.
                credential = await AuthenticationManager.Current.GenerateCredentialAsync(info.ServiceUri);
            }
            catch (Exception)
            {
                // Exception will be reported in calling function.
                throw;
            }

            return credential;
        }
    }
    #endregion
}
XAML
<UserControl 
    x:Class="ArcGISRuntime.UWP.Samples.GenerateOfflineMap.GenerateOfflineMap"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:esriUI="using:Esri.ArcGISRuntime.UI.Controls">
    <Grid>
        <esriUI:MapView x:Name="MyMapView"/>

        <Border x:Name="takeOfflineArea" Background="White" BorderBrush="Black" BorderThickness="1"
                HorizontalAlignment="Right" VerticalAlignment="Top"
                Margin="30" Padding="20" Width="375">
            <StackPanel HorizontalAlignment="Center" VerticalAlignment="Center">
                <Button x:Name="TakeMapOfflineButton" 
                        Width="250"
                        Click="TakeMapOfflineButton_Click" 
                        IsEnabled="True" 
                        Content="Take map offline"/>
            </StackPanel>
        </Border>

        <Border x:Name="messageArea" Visibility="Collapsed"
                Background="White" BorderBrush="Black" BorderThickness="1"
                HorizontalAlignment="Right" VerticalAlignment="Top"
                Margin="30" Padding="5" Width="450">
            <StackPanel>
                <TextBlock HorizontalAlignment="Center" VerticalAlignment="Center" Margin="10"
                           FontWeight="Bold" 
                           Text="Map is offline!"/>
            </StackPanel>
        </Border>

        <Grid x:Name="busyIndicator" Background="#807f7f7f" Visibility="Collapsed">
            <Grid HorizontalAlignment="Center" VerticalAlignment="Center">
                <Grid.RowDefinitions>
                    <RowDefinition Height="auto"/>
                    <RowDefinition Height="auto"/>
                    <RowDefinition Height="auto"/>
                </Grid.RowDefinitions>
                <TextBlock HorizontalAlignment="Center" VerticalAlignment="Center" Margin="10"
                           Foreground="White" FontSize="18">
                    <Run Text="Generating offline map... "></Run>
                    <Run x:Name="Percentage" Text=""></Run>
                </TextBlock>
                <ProgressBar x:Name="progressBar"
                             Grid.Row="1" 
                             Minimum="0" Maximum="100"
                             IsEnabled="True"
                             HorizontalAlignment="Center" VerticalAlignment="Center" 
                             Width="100" Height="10" Margin="0,0,0,10"/>
                <Button x:Name="CancelJobButton" 
                        Grid.Row="3"
                        Content="Cancel" 
                        Click="CancelJobButton_Click" 
                        HorizontalAlignment="Center" 
                        Width="100"/>
            </Grid>
        </Grid>
        <Grid x:Name="loadingIndicator" 
              Background="#807f7f7f" 
              Visibility="Visible">
            <Grid HorizontalAlignment="Center" VerticalAlignment="Center">
                <Grid.RowDefinitions>
                    <RowDefinition Height="auto"/>
                    <RowDefinition Height="auto"/>
                </Grid.RowDefinitions>
                <TextBlock Text="Loading online map..." 
                           Foreground="White" FontSize="18"
                           Margin="10"/>
                <ProgressBar Grid.Row="1"
                             IsEnabled="True" IsIndeterminate="True" 
                             Width="100" Height="10" 
                             HorizontalAlignment="Center" VerticalAlignment="Center"/>
            </Grid>
        </Grid>
    </Grid>
</UserControl>
Examples

Xamarin Forms UWP

Example Name: GenerateOfflineMap

Take a web map offline.

Code example screen shot.

C#
// Copyright 2018 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: http://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.

using Esri.ArcGISRuntime.Geometry;
using Esri.ArcGISRuntime.Mapping;
using Esri.ArcGISRuntime.Portal;
using Esri.ArcGISRuntime.Symbology;
using Esri.ArcGISRuntime.Tasks;
using Esri.ArcGISRuntime.Tasks.Offline;
using Esri.ArcGISRuntime.UI;
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Threading.Tasks;
using Xamarin.Forms;
using Esri.ArcGISRuntime.Security;

#if __IOS__
using Xamarin.Auth;
using Xamarin.Forms.Platform.iOS;
using UIKit;
#endif

#if __ANDROID__
using Android.App;
using Application = Xamarin.Forms.Application;
using Xamarin.Auth;
#endif

namespace ArcGISRuntime.Samples.GenerateOfflineMap
{
    [ArcGISRuntime.Samples.Shared.Attributes.Sample(
        name: "Generate offline map",
        category: "Map",
        description: "Take a web map offline.",
        instructions: "When the app starts, you will be prompted to sign in using a free ArcGIS Online account. Once the map loads, zoom to the extent you want to take offline. The red border shows the extent that will be downloaded. Tap the \"Take Map Offline\" button to start the offline map job. The progress bar will show the job's progress. When complete, the offline map will replace the online map in the map view.",
        tags: new[] { "download", "offline", "save", "web map" })]
    public partial class GenerateOfflineMap : ContentPage, IOAuthAuthorizeHandler
    {
        // The job to generate an offline map.
        private GenerateOfflineMapJob _generateOfflineMapJob;

        // The extent of the data to take offline.
        private Envelope _areaOfInterest = new Envelope(-88.1541, 41.7690, -88.1471, 41.7720, SpatialReferences.Wgs84);

        // The ID for a web map item hosted on the server (water network map of Naperville IL).
        private string WebMapId = "acc027394bc84c2fb04d1ed317aac674";

        public GenerateOfflineMap()
        {
            InitializeComponent();

            // Load the web map, show area of interest, restrict map interaction, and set up authorization. 
            Initialize();
        }

        private async void Initialize()
        {
            try
            {
                // Call a function to set up the AuthenticationManager for OAuth.
                SetOAuthInfo();

                // Create the ArcGIS Online portal.
                ArcGISPortal portal = await ArcGISPortal.CreateAsync();

                // Get the Naperville water web map item using its ID.
                PortalItem webmapItem = await PortalItem.CreateAsync(portal, WebMapId);

                // Create a map from the web map item.
                Map onlineMap = new Map(webmapItem);

                // Display the map in the MapView.
                MyMapView.Map = onlineMap;

                // Disable user interactions on the map (no panning or zooming from the initial extent).
                MyMapView.InteractionOptions = new MapViewInteractionOptions
                {
                    IsEnabled = false
                };

                // Create a graphics overlay for the extent graphic and apply a renderer.
                SimpleLineSymbol aoiOutlineSymbol = new SimpleLineSymbol(SimpleLineSymbolStyle.Solid, System.Drawing.Color.Red, 3);
                GraphicsOverlay extentOverlay = new GraphicsOverlay
                {
                    Renderer = new SimpleRenderer(aoiOutlineSymbol)
                };
                MyMapView.GraphicsOverlays.Add(extentOverlay);

                // Add a graphic to show the area of interest (extent) that will be taken offline.
                Graphic aoiGraphic = new Graphic(_areaOfInterest);
                extentOverlay.Graphics.Add(aoiGraphic);

                // Hide the map loading progress indicator.
                loadingIndicator.IsVisible = false;
            }
            catch (Exception ex)
            {
                await Application.Current.MainPage.DisplayAlert("Alert", ex.ToString(), "OK");
            }
        }

        private async void TakeMapOfflineButton_Click(object sender, EventArgs e)
        {
            // Clean up any previous outputs in the temp directory.
            string tempPath = $"{Path.GetTempPath()}";
            string[] outputFolders = Directory.GetDirectories(tempPath, "NapervilleWaterNetwork*");

            // Loop through the folder names and delete them.
            foreach (string dir in outputFolders)
            {
                try
                {
                    // Delete the folder.
                    Directory.Delete(dir, true);
                }
                catch (Exception)
                {
                    // Ignore exceptions (files might be locked, for example).
                }
            }

            // Create a new folder for the output mobile map.
            string packagePath = Path.Combine(tempPath, @"NapervilleWaterNetwork");
            int num = 1;
            while (Directory.Exists(packagePath))
            {
                packagePath = Path.Combine(tempPath, @"NapervilleWaterNetwork" + num.ToString());
                num++;
            }

            // Create the output directory.
            Directory.CreateDirectory(packagePath);

            try
            {
                // Show the progress indicator while the job is running.
                busyIndicator.IsVisible = true;

                // Create an offline map task with the current (online) map.
                OfflineMapTask takeMapOfflineTask = await OfflineMapTask.CreateAsync(MyMapView.Map);

                // Create the default parameters for the task, pass in the area of interest.
                GenerateOfflineMapParameters parameters = await takeMapOfflineTask.CreateDefaultGenerateOfflineMapParametersAsync(_areaOfInterest);

                // Create the job with the parameters and output location.
                _generateOfflineMapJob = takeMapOfflineTask.GenerateOfflineMap(parameters, packagePath);

                // Handle the progress changed event for the job.
                _generateOfflineMapJob.ProgressChanged += OfflineMapJob_ProgressChanged;

                // Await the job to generate geodatabases, export tile packages, and create the mobile map package.
                GenerateOfflineMapResult results = await _generateOfflineMapJob.GetResultAsync();

                // Check for job failure (writing the output was denied, e.g.).
                if (_generateOfflineMapJob.Status != JobStatus.Succeeded)
                {
                    await Application.Current.MainPage.DisplayAlert("Alert", "Generate offline map package failed.", "OK");
                    busyIndicator.IsVisible = false;
                }

                // Check for errors with individual layers.
                if (results.LayerErrors.Any())
                {
                    // Build a string to show all layer errors.
                    System.Text.StringBuilder errorBuilder = new System.Text.StringBuilder();
                    foreach (KeyValuePair<Layer, Exception> layerError in results.LayerErrors)
                    {
                        errorBuilder.AppendLine(string.Format("{0} : {1}", layerError.Key.Id, layerError.Value.Message));
                    }

                    // Show layer errors.
                    string errorText = errorBuilder.ToString();
                    await Application.Current.MainPage.DisplayAlert("Alert", errorText, "OK");
                }

                // Display the offline map.
                MyMapView.Map = results.OfflineMap;

                // Apply the original viewpoint for the offline map.
                MyMapView.SetViewpoint(new Viewpoint(_areaOfInterest));

                // Enable map interaction so the user can explore the offline data.
                MyMapView.InteractionOptions.IsEnabled = true;

                // Hide the "Take map offline" button.
                takeOfflineArea.IsVisible = false;

                // Show a message that the map is offline.
                messageArea.IsVisible = true;
            }
            catch (TaskCanceledException)
            {
                // Generate offline map task was canceled.
                await Application.Current.MainPage.DisplayAlert("Alert", "Taking map offline was canceled", "OK");
            }
            catch (Exception ex)
            {
                // Exception while taking the map offline.
                await Application.Current.MainPage.DisplayAlert("Alert", ex.Message, "OK");
            }
            finally
            {
                // Hide the activity indicator when the job is done.
                busyIndicator.IsVisible = false;
            }
        }

        // Show changes in job progress.
        private void OfflineMapJob_ProgressChanged(object sender, EventArgs e)
        {
            // Get the job.
            GenerateOfflineMapJob job = sender as GenerateOfflineMapJob;

            // Dispatch to the UI thread.
            Device.BeginInvokeOnMainThread(() =>
            { 
                // Show the percent complete and update the progress bar.
                Percentage.Text = job.Progress > 0 ? job.Progress.ToString() + " %" : string.Empty;
                progressBar.Progress = job.Progress / 100.0;
            });
        }

        private void CancelJobButton_Click(object sender, EventArgs e)
        {
            // The user canceled the job.
            _generateOfflineMapJob.Cancel();
        }

        #region Authentication
        // Constants for OAuth-related values.
        // - The URL of the portal to authenticate with (ArcGIS Online).
        private const string ServerUrl = "https://www.arcgis.com/sharing/rest";
        // - The Client ID for an app registered with the server (the ID below is for a public app created by the ArcGIS Runtime team).
        private const string AppClientId = @"6wMAmbUEX1rvsOb4";
        // - A URL for redirecting after a successful authorization (this must be a URL configured with the app).
        private const string OAuthRedirectUrl = @"forms-samples-app://auth";

        private void SetOAuthInfo()
        {
            // Register the server information with the AuthenticationManager.
            ServerInfo serverInfo = new ServerInfo
            {
                ServerUri = new Uri(ServerUrl),
                TokenAuthenticationType = TokenAuthenticationType.OAuthImplicit,
                OAuthClientInfo = new OAuthClientInfo
                {
                    ClientId = AppClientId,
                    RedirectUri = new Uri(OAuthRedirectUrl)
                }
            };

            // Register this server with AuthenticationManager.
            AuthenticationManager.Current.RegisterServer(serverInfo);

            // Use a function in this class to challenge for credentials.
            AuthenticationManager.Current.ChallengeHandler = new ChallengeHandler(CreateCredentialAsync);

            // Set the OAuthAuthorizeHandler component (this class) for Android or iOS platforms.
#if __ANDROID__ || __IOS__
            AuthenticationManager.Current.OAuthAuthorizeHandler = this;
#endif
        }

        // ChallengeHandler function that will be called whenever access to a secured resource is attempted.
        public async Task<Credential> CreateCredentialAsync(CredentialRequestInfo info)
        {
            Credential credential = null;

            try
            {
                // IOAuthAuthorizeHandler will challenge the user for OAuth credentials.
                credential = await AuthenticationManager.Current.GenerateCredentialAsync(info.ServiceUri);
            }
            catch (TaskCanceledException) { return credential; }
            catch (Exception)
            {
                // Exception will be reported in calling function.
                throw;
            }

            return credential;
        }

        #region IOAuthAuthorizationHandler implementation
        // Use a TaskCompletionSource to track the completion of the authorization.
        private TaskCompletionSource<IDictionary<string, string>> _taskCompletionSource;

        // IOAuthAuthorizeHandler.AuthorizeAsync implementation.
        public Task<IDictionary<string, string>> AuthorizeAsync(Uri serviceUri, Uri authorizeUri, Uri callbackUri)
        {
            // If the TaskCompletionSource is not null, authorization may already be in progress and should be canceled.
            if (_taskCompletionSource != null)
            {
                // Try to cancel any existing authentication task.
                _taskCompletionSource.TrySetCanceled();
            }

            // Create a task completion source.
            _taskCompletionSource = new TaskCompletionSource<IDictionary<string, string>>();
#if __ANDROID__ || __IOS__

#if __ANDROID__
            // Get the current Android Activity.
            Activity activity = (Activity)ArcGISRuntime.Droid.MainActivity.Instance;
#endif
#if __IOS__
            // Get the current iOS ViewController.
            UIViewController viewController = null;
            Device.BeginInvokeOnMainThread(() =>
            {
                viewController = UIApplication.SharedApplication.KeyWindow.RootViewController;
            });
#endif
            // Create a new Xamarin.Auth.OAuth2Authenticator using the information passed in.
            OAuth2Authenticator authenticator = new OAuth2Authenticator(
                clientId: AppClientId,
                scope: "",
                authorizeUrl: authorizeUri,
                redirectUrl: callbackUri)
            {
                ShowErrors = false,
                // Allow the user to cancel the OAuth attempt.
                AllowCancel = true
            };

            // Define a handler for the OAuth2Authenticator.Completed event.
            authenticator.Completed += (sender, authArgs) =>
            {
                try
                {
#if __IOS__
                    // Dismiss the OAuth UI when complete.
                    viewController.DismissViewController(true, null);
#endif

                    // Check if the user is authenticated.
                    if (authArgs.IsAuthenticated)
                    {
                        // If authorization was successful, get the user's account.
                        Xamarin.Auth.Account authenticatedAccount = authArgs.Account;

                        // Set the result (Credential) for the TaskCompletionSource.
                        _taskCompletionSource.SetResult(authenticatedAccount.Properties);
                    }
                    else
                    {
                        throw new Exception("Unable to authenticate user.");
                    }
                }
                catch (Exception ex)
                {
                    // If authentication failed, set the exception on the TaskCompletionSource.
                    _taskCompletionSource.TrySetException(ex);

                    // Cancel authentication.
                    authenticator.OnCancelled();
                }
                finally
                {
                    // Dismiss the OAuth login.
#if __ANDROID__ 
                    activity.FinishActivity(99);
#endif
                }
            };

            // If an error was encountered when authenticating, set the exception on the TaskCompletionSource.
            authenticator.Error += (sndr, errArgs) =>
            {
                // If the user cancels, the Error event is raised but there is no exception ... best to check first.
                if (errArgs.Exception != null)
                {
                    _taskCompletionSource.TrySetException(errArgs.Exception);
                }
                else
                {
                    // Login canceled: dismiss the OAuth login.
                    if (_taskCompletionSource != null)
                    {
                        _taskCompletionSource.TrySetCanceled();
#if __ANDROID__ 
                        activity.FinishActivity(99);
#endif
                    }
                }

                // Cancel authentication.
                authenticator.OnCancelled();
            };

            // Present the OAuth UI so the user can enter user name and password.
#if __ANDROID__
            Android.Content.Intent intent = authenticator.GetUI(activity);
            activity.StartActivityForResult(intent, 99);
#endif
#if __IOS__
            // Present the OAuth UI (on the app's UI thread) so the user can enter user name and password.
            Device.BeginInvokeOnMainThread(() =>
            {
                viewController.PresentViewController(authenticator.GetUI(), true, null);
            });
#endif

#endif // (If Android or iOS)
            // Return completion source task so the caller can await completion.
            return _taskCompletionSource.Task;
        }
        #endregion

        #endregion
    }
}
XAML
<?xml version="1.0" encoding="utf-8" ?>
<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"             
             xmlns:esriUI="clr-namespace:Esri.ArcGISRuntime.Xamarin.Forms;assembly=Esri.ArcGISRuntime.Xamarin.Forms"
             x:Class="ArcGISRuntime.Samples.GenerateOfflineMap.GenerateOfflineMap">
    <Grid>
        <esriUI:MapView x:Name="MyMapView"/>

        <Frame x:Name="takeOfflineArea" 
               BackgroundColor="White" BorderColor="Black"
               HorizontalOptions="End" VerticalOptions="Start"
               Margin="30" Padding="20" WidthRequest="375">
            <StackLayout HorizontalOptions="Center" VerticalOptions="Center">
                <Button x:Name="TakeMapOfflineButton" 
                        WidthRequest="250"
                        Clicked="TakeMapOfflineButton_Click" 
                        IsEnabled="True" 
                        Text="Take map offline"/>
            </StackLayout>
        </Frame>

        <Frame x:Name="messageArea" 
               IsVisible="False"
               BackgroundColor="White" BorderColor="Black"
               HorizontalOptions="End" VerticalOptions="Start"
               Margin="30" Padding="5" WidthRequest="450">
            <StackLayout>
                <Label HorizontalOptions="Center" VerticalOptions="Center" Margin="10"
                       Text="Map is offline!"/>
            </StackLayout>
        </Frame>

        <Grid x:Name="busyIndicator" BackgroundColor="#807f7f7f" IsVisible="False">
            <Grid HorizontalOptions="Center" VerticalOptions="Center">
                <Grid.RowDefinitions>
                    <RowDefinition Height="auto"/>
                    <RowDefinition Height="auto"/>
                    <RowDefinition Height="auto"/>
                </Grid.RowDefinitions>
                <Label HorizontalOptions="Center" VerticalOptions="Center" Margin="10"
                       TextColor="White" FontSize="18">
                    <Label.FormattedText>
                        <FormattedString>
                            <Span Text="Generating offline map... "/>
                            <Span x:Name="Percentage" Text=""/>
                        </FormattedString>
                    </Label.FormattedText>
                </Label>
                <ProgressBar x:Name="progressBar"
                             Grid.Row="1"
                             IsEnabled="True"
                             HorizontalOptions="Center" VerticalOptions="Center" 
                             WidthRequest="100" HeightRequest="10" Margin="0,0,0,10"/>
                <Button x:Name="CancelJobButton" 
                        Grid.Row="3"
                        Text="Cancel" 
                        Clicked="CancelJobButton_Click" 
                        HorizontalOptions="Center" 
                        WidthRequest="100"/>
            </Grid>
        </Grid>
        <Grid x:Name="loadingIndicator" 
              BackgroundColor="#807f7f7f" 
              IsVisible="True">
            <Grid HorizontalOptions="Center" VerticalOptions="Center">
                <Grid.RowDefinitions>
                    <RowDefinition Height="auto"/>
                    <RowDefinition Height="auto"/>
                </Grid.RowDefinitions>
                <Label Text="Loading online map..." 
                           TextColor="White" FontSize="18"
                           Margin="10"/>
                <ProgressBar Grid.Row="1"
                             IsEnabled="True"
                             WidthRequest="100" HeightRequest="10" 
                             HorizontalOptions="Center" VerticalOptions="Center"/>
            </Grid>
        </Grid>
    </Grid>
</ContentPage>
See Also
Additional Examples
Hyperlink to ExampleDescription
GenerateOfflineMapTake a web map offline.
GenerateOfflineMapWithOverridesTake a web map offline with additional options for each layer.
OfflineBasemapByReferenceUse the `OfflineMapTask` to take a web map offline, but instead of downloading an online basemap, use one which is already on the device.