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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: 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.Symbology;
using Esri.ArcGISRuntime.UI.Controls;
using System;
using Color = System.Drawing.Color;
namespaceArcGISRuntimeXamarin.Samples.DisplayOACollection{
[Activity(ConfigurationChanges = Android.Content.PM.ConfigChanges.Orientation | Android.Content.PM.ConfigChanges.ScreenSize)]
[ArcGISRuntime.Samples.Shared.Attributes.Sample(
name: "Display OGC API collection",
category: "Layers",
description: "Display an OGC API feature collection and query features while navigating the map view.",
instructions: "Pan the map and observe how new features are loaded from the OGC API feature service.",
tags: new[] { "OGC", "OGC API", "feature", "feature layer", "feature table", "service", "table", "web" })]
publicclassDisplayOACollection : Activity {
// Hold references to the UI controls.private MapView _myMapView;
private ProgressBar _loadingProgressBar;
// Hold a reference to the OGC feature collection table.private OgcFeatureCollectionTable _featureTable;
// Constants for the service URL and collection id.privateconststring ServiceUrl = "https://demo.ldproxy.net/daraa";
// Note that the service defines the collection id which can be accessed via OgcFeatureCollectionInfo.CollectionId.privateconststring CollectionId = "TransportationGroundCrv";
protectedoverridevoidOnCreate(Bundle bundle) {
base.OnCreate(bundle);
Title = "Display OGC API collection";
CreateLayout();
Initialize();
}
privateasyncvoidInitialize() {
// Create the map with topographic basemap. _myMapView.Map = new Map(BasemapStyle.ArcGISTopographic);
try {
// Create the feature table from URI and collection id. _featureTable = new OgcFeatureCollectionTable(new Uri(ServiceUrl), CollectionId);
// Set the feature request mode to manual (only manual is currently supported).// In this mode, you must manually populate the table - panning and zooming won't request features automatically. _featureTable.FeatureRequestMode = FeatureRequestMode.ManualCache;
// Load the table.await _featureTable.LoadAsync();
// Create a feature layer to visualize the OAFeat features. FeatureLayer ogcFeatureLayer = new FeatureLayer(_featureTable);
// Apply a renderer. ogcFeatureLayer.Renderer = new SimpleRenderer(new SimpleLineSymbol(SimpleLineSymbolStyle.Solid, Color.Blue, 3));
// Add the layer to the map. _myMapView.Map.OperationalLayers.Add(ogcFeatureLayer);
// Use the navigation completed event to populate the table with the features needed for the current extent. _myMapView.NavigationCompleted += MapView_NavigationCompleted;
// Zoom to a small area within the dataset by default. Envelope datasetExtent = _featureTable.Extent;
if (datasetExtent != null && !datasetExtent.IsEmpty)
{
await _myMapView.SetViewpointGeometryAsync(new Envelope(datasetExtent.GetCenter(), datasetExtent.Width / 3, datasetExtent.Height / 3));
}
}
catch (Exception ex)
{
new AlertDialog.Builder(this).SetMessage(ex.Message).SetTitle("Error").Show();
}
}
privateasyncvoidMapView_NavigationCompleted(object sender, EventArgs e) {
// Show the loading bar. _loadingProgressBar.Visibility = ViewStates.Visible;
// Get the current extent. Envelope currentExtent = _myMapView.VisibleArea.Extent;
// Create a query based on the current visible extent. QueryParameters visibleExtentQuery = new QueryParameters();
visibleExtentQuery.Geometry = currentExtent;
visibleExtentQuery.SpatialRelationship = SpatialRelationship.Intersects;
// Set a limit of 5000 on the number of returned features per request,// because the default on some services could be as low as 10. visibleExtentQuery.MaxFeatures = 5000;
try {
// Populate the table with the query, leaving existing table entries intact.// Setting outFields to null requests all fields.await _featureTable.PopulateFromServiceAsync(visibleExtentQuery, false, null);
}
catch (Exception ex)
{
new AlertDialog.Builder(this).SetMessage(ex.Message).SetTitle("Couldn't populate table.").Show();
}
finally {
// Hide the loading bar. _loadingProgressBar.Visibility = ViewStates.Gone;
}
}
privatevoidCreateLayout() {
// Create a new vertical layout for the app.var layout = new LinearLayout(this) { Orientation = Orientation.Vertical };
// Add a help label. TextView helpLabel = new TextView(this);
helpLabel.Gravity = GravityFlags.Center;
helpLabel.Text = "Pan and zoom to see features.";
layout.AddView(helpLabel);
// Add a progress bar. _loadingProgressBar = new ProgressBar(this);
_loadingProgressBar.Indeterminate = true;
_loadingProgressBar.Visibility = ViewStates.Gone;
layout.AddView(_loadingProgressBar);
// Add the map view to the layout. _myMapView = new MapView(this);
layout.AddView(_myMapView);
// Show the layout in the app. SetContentView(layout);
}
}
}