Update attributes (feature service)

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Update feature attributes in an online feature service.

Image of update attributes feature service

Use case

Online feature services can be updated with new data. This is useful for updating existing data in real time while working in the field.

How to use the sample

To change the feature's damage property, tap the feature to select it, and update the damage type using the drop down.

How it works

  1. Create a ServiceFeatureTable object from a URL.

    • When the table loads, you can get the domain to determine which options to present in your UI.
  2. Create a FeatureLayer object from the ServiceFeatureTable.
  3. Select features from the FeatureLayer.
  4. To update the feature's attribute, first load it, then use the SetAttributeValue.
  5. Update the table with UpdateFeatureAsync.
  6. After a change, apply the changes on the server using ApplyEditsAsync.

Relevant API

  • ArcGISFeature
  • FeatureLayer
  • ServiceFeatureTable

Tags

amend, attribute, details, edit, editing, information, value

Sample Code

UpdateAttributes.cs
                                                                                                                                                                                                                                        
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// Copyright 2019 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 Android.App;
using Android.OS;
using Android.Views;
using Android.Widget;
using Esri.ArcGISRuntime.Data;
using Esri.ArcGISRuntime.Geometry;
using Esri.ArcGISRuntime.Mapping;
using Esri.ArcGISRuntime.UI.Controls;
using System;
using System.Linq;

namespace ArcGISRuntimeXamarin.Samples.UpdateAttributes
{
    [Activity (ConfigurationChanges=Android.Content.PM.ConfigChanges.Orientation | Android.Content.PM.ConfigChanges.ScreenSize)]
    [ArcGISRuntime.Samples.Shared.Attributes.Sample(
        name: "Update attributes (feature service)",
        category: "Data",
        description: "Update feature attributes in an online feature service.",
        instructions: "To change the feature's damage property, tap the feature to select it, and update the damage type using the drop down.",
        tags: new[] { "amend", "attribute", "details", "edit", "editing", "information", "value" })]
    public class UpdateAttributes : Activity
    {
        // Hold a reference to the MapView.
        private MapView _myMapView;

        // URL to the feature service.
        private const string FeatureServiceUrl = "https://sampleserver6.arcgisonline.com/arcgis/rest/services/DamageAssessment/FeatureServer/0";

        // Name of the field that will be updated.
        private const string AttributeFieldName = "typdamage";

        // Hold a reference to the feature layer.
        private FeatureLayer _damageLayer;

        // Hold a reference to the selected feature.
        private ArcGISFeature _selectedFeature;

        // Hold a reference to the domain.
        private CodedValueDomain _domain;

        protected override void OnCreate(Bundle bundle)
        {
            base.OnCreate(bundle);

            Title = "Update attributes (feature service)";

            CreateLayout();
            Initialize();
        }

        private void Initialize()
        {
            // Create the map with streets basemap.
            _myMapView.Map = new Map(BasemapStyle.ArcGISStreets);

            // Create the feature table, referring to the Damage Assessment feature service.
            ServiceFeatureTable damageTable = new ServiceFeatureTable(new Uri(FeatureServiceUrl));

            // When the table loads, use it to discover the domain of the typdamage field.
            damageTable.Loaded += DamageTable_Loaded;

            // Create a feature layer to visualize the features in the table.
            _damageLayer = new FeatureLayer(damageTable);

            // Add the layer to the map.
            _myMapView.Map.OperationalLayers.Add(_damageLayer);

            // Zoom to the United States.
            _myMapView.SetViewpointCenterAsync(new MapPoint(-10800000, 4500000, SpatialReferences.WebMercator), 3e7);
        }

        private void DamageTable_Loaded(object sender, EventArgs e)
        {
            // This code needs to work with the UI, so it needs to run on the UI thread.
            RunOnUiThread(() =>
            {
                // Get the relevant field from the table.
                ServiceFeatureTable table = (ServiceFeatureTable) sender;
                Field typeDamageField = table.Fields.First(field => field.Name == AttributeFieldName);

                // Get the domain for the field.
                _domain = (CodedValueDomain) typeDamageField.Domain;

                // Listen for user taps on the map - this will select the feature.
                _myMapView.GeoViewTapped += MapView_Tapped;
            });
        }

        private async void MapView_Tapped(object sender, GeoViewInputEventArgs e)
        {
            // Clear any existing selection.
            _damageLayer.ClearSelection();

            // Dismiss any existing callouts.
            _myMapView.DismissCallout();

            try
            {
                // Perform an identify to determine if a user tapped on a feature.
                IdentifyLayerResult identifyResult = await _myMapView.IdentifyLayerAsync(_damageLayer, e.Position, 8, false);

                // Do nothing if there are no results.
                if (!identifyResult.GeoElements.Any())
                {
                    return;
                }

                // Get the tapped feature.
                _selectedFeature = (ArcGISFeature)identifyResult.GeoElements.First();

                // Select the feature.
                _damageLayer.SelectFeature(_selectedFeature);

                // Update the UI for the selection.
                ShowFeatureOptions();
            }
            catch (Exception ex)
            {
                ShowMessage("Error selecting feature.", ex.ToString());
            }
        }

        private void ShowFeatureOptions()
        {
            // Get the current value.
            string currentAttributeValue = _selectedFeature.Attributes[AttributeFieldName].ToString();

            // Set up the UI for the callout.
            Button changeValueButton = new Button(this);
            changeValueButton.Text = $"{currentAttributeValue} - Edit";
            changeValueButton.Click += ShowDamageTypeChoices;

            // Show the callout.
            _myMapView.ShowCalloutAt((MapPoint) _selectedFeature.Geometry, changeValueButton);
        }

        private void ShowDamageTypeChoices(object sender, EventArgs e)
        {
            // Create menu to show options.
            PopupMenu menu = new PopupMenu(this, (Button) sender);
            menu.MenuItemClick += (o, menuArgs) => { UpdateDamageType(menuArgs.Item.ToString()); };

            // Create menu options.
            foreach (CodedValue codeValue in _domain.CodedValues)
            {
                menu.Menu.Add(codeValue.Name);
            }

            // Show menu in the view.
            menu.Show();
        }

        private async void UpdateDamageType(string selectedAttributeValue)
        {
            try
            {
                // Load the feature.
                await _selectedFeature.LoadAsync();

                if (_selectedFeature.Attributes[AttributeFieldName].ToString() == selectedAttributeValue)
                {
                    throw new Exception("Old and new attribute values are the same.");
                }

                // Update the attribute value.
                _selectedFeature.SetAttributeValue(AttributeFieldName, selectedAttributeValue);

                // Update the table.
                await _selectedFeature.FeatureTable.UpdateFeatureAsync(_selectedFeature);

                // Update the service.
                ServiceFeatureTable table = (ServiceFeatureTable) _selectedFeature.FeatureTable;
                await table.ApplyEditsAsync();

                ShowMessage("Success!", $"Edited feature {_selectedFeature.Attributes["objectid"]}");
            }
            catch (Exception ex)
            {
                ShowMessage("Failed to edit feature", ex.Message);
            }
            finally
            {
                // Clear the selection.
                _damageLayer.ClearSelection();
                _selectedFeature = null;

                // Dismiss any callout.
                _myMapView.DismissCallout();
            }
        }

        private void ShowMessage(string title, string message)
        {
            // Display the message to the user.
            AlertDialog.Builder builder = new AlertDialog.Builder(this);
            builder.SetMessage(message).SetTitle(title).Show();
        }

        private void CreateLayout()
        {
            // Create a new vertical layout for the app.
            var layout = new LinearLayout(this) {Orientation = Orientation.Vertical};

            // Create the MapView.
            _myMapView = new MapView(this);

            // Create the help label.
            TextView helpLabel = new TextView(this);
            helpLabel.Text = "Tap to select a feature to edit.";
            helpLabel.TextAlignment = TextAlignment.Center;
            helpLabel.Gravity = GravityFlags.Center;

            // Add the help label to the layout.
            layout.AddView(helpLabel);

            // Add the map view to the layout.
            layout.AddView(_myMapView);

            // Show the layout in the app.
            SetContentView(layout);
        }
    }
}

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