Read GeoPackage

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// 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 ArcGISRuntime.Samples.Managers;
using Esri.ArcGISRuntime.Data;
using Esri.ArcGISRuntime.Mapping;
using Esri.ArcGISRuntime.Rasters;
using Esri.ArcGISRuntime.UI.Controls;
using Foundation;
using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Linq;
using UIKit;

namespace ArcGISRuntime.Samples.ReadGeoPackage
{
    [Register("ReadGeoPackage")]
    [Shared.Attributes.OfflineData("68ec42517cdd439e81b036210483e8e7")]
    [ArcGISRuntime.Samples.Shared.Attributes.Sample(
        name: "Read GeoPackage",
        category: "Data",
        description: "Add rasters and feature tables from a GeoPackage to a map.",
        instructions: "When the sample loads, the feature tables and rasters from the GeoPackage will be shown on the map.",
        tags: new[] { "GeoPackage", "OGC", "container", "layer", "map", "package", "raster", "table" })]
    public class ReadGeoPackage : UIViewController
    {
        // Hold references to UI controls.
        private MapView _myMapView;
        private UIBarButtonItem _addLayerButton;
        private UIBarButtonItem _removeLayerButton;

        // Dictionary associates names with layers.
        private readonly Dictionary<string, Layer> _nameToLayerDictionary = new Dictionary<string, Layer>();

        // Names of layers not being displayed.
        private readonly ObservableCollection<string> _layersNotInMap = new ObservableCollection<string>();

        // Names of layers being displayed.
        private readonly ObservableCollection<string> _layersInMap = new ObservableCollection<string>();

        public ReadGeoPackage()
        {
            Title = "Read a GeoPackage";
        }

        private async void Initialize()
        {
            // Create a new map centered on Aurora Colorado.
            _myMapView.Map = new Map(BasemapStyle.ArcGISStreets);
            _myMapView.Map.InitialViewpoint = new Viewpoint(39.7294, -104.70, 175000);

            // Get the full path to the GeoPackage on the device.
            string geoPackagePath = DataManager.GetDataFolder("68ec42517cdd439e81b036210483e8e7", "AuroraCO.gpkg");

            try
            {
                // Open the GeoPackage.
                GeoPackage geoPackage = await GeoPackage.OpenAsync(geoPackagePath);

                // Loop through each GeoPackageRaster.
                foreach (GeoPackageRaster oneGeoPackageRaster in geoPackage.GeoPackageRasters)
                {
                    // Create a RasterLayer from the GeoPackageRaster.
                    RasterLayer rasterLayer = new RasterLayer(oneGeoPackageRaster)
                    {
                        // Set the opacity on the RasterLayer to partially visible.
                        Opacity = 0.55
                    };

                    // Load the RasterLayer - that way we can get to its properties.
                    await rasterLayer.LoadAsync();

                    // Create a string variable to hold the human-readable name of the RasterLayer for display.
                    string rasterLayerName = "";

                    if (rasterLayer.Name != "")
                    {
                        // We have a good human-readable name for the RasterLayer that came from the RasterLayer.Name property.
                        rasterLayerName = rasterLayer.Name;
                    }
                    else if (oneGeoPackageRaster.Path.Split('/').Last() != "")
                    {
                        // We did not get a good human-readable name from the RasterLayer from the .Name
                        // property, get the good human-readable name from the GeoPackageRaster.Path instead.
                        rasterLayerName = oneGeoPackageRaster.Path.Split('/').Last();
                    }

                    // Append the 'type of layer' to the raster layer name string to display in the ListBox and as the key for the dictionary.
                    rasterLayerName = $"{rasterLayerName} - RasterLayer";

                    // Check if a layer has already been added from the geopackage.
                    if (_nameToLayerDictionary.ContainsKey(rasterLayerName)) continue;

                    // Add the name of the RasterLayer and the RasterLayer itself into the dictionary.
                    _nameToLayerDictionary[rasterLayerName] = rasterLayer;

                    // Add the name of the RasterLayer to the layers not in the map collection
                    // which displays the human-readable layer names used by the UISegmentedControl.
                    _layersNotInMap.Add(rasterLayerName);
                }

                // Loop through each GeoPackageFeatureTable from the GeoPackage.
                foreach (GeoPackageFeatureTable oneGeoPackageFeatureTable in geoPackage.GeoPackageFeatureTables)
                {
                    // Create a FeatureLayer from the GeoPackageFeatureLayer.
                    FeatureLayer featureLayer = new FeatureLayer(oneGeoPackageFeatureTable);

                    // Load the FeatureLayer - that way we can get to its properties.
                    await featureLayer.LoadAsync();

                    // Create a string variable to hold the human-readable name of the FeatureLayer for display in the UISegmentedControl and the dictionary.
                    string featureLayerName = featureLayer.Name;

                    // Append the 'type of layer' to the feature layer name string to display in the ListBox and as the key for the dictionary.
                    featureLayerName = $"{featureLayerName} - FeatureLayer";

                    // Check if a layer has already been added from the geopackage.
                    if (_nameToLayerDictionary.ContainsKey(featureLayerName)) continue;

                    // Add the name of the FeatureLayer and the FeatureLayer itself into the dictionary.
                    _nameToLayerDictionary[featureLayerName] = featureLayer;

                    // Add the name of the RasterLayer to the collection of layers not in the map which displays the human-readable layer names used by the UISegmentedControl.
                    _layersNotInMap.Add(featureLayerName);
                }

                // Enable the UI.
                _addLayerButton.Enabled = true;
                _removeLayerButton.Enabled = true;
            }
            catch (Exception e)
            {
                new UIAlertView("Error", e.ToString(), (IUIAlertViewDelegate)null, "OK", null).Show();
            }
        }

        private void AddLayerToMap_Clicked(object sender, EventArgs e)
        {
            // Create a new Alert Controller - this will show the layer names that can be added to the map.
            UIAlertController alertController = UIAlertController.Create(null, "Add a layer to the map", UIAlertControllerStyle.ActionSheet);

            // Add actions to add a layer to the map.
            foreach (string oneLayerName in _layersNotInMap)
            {
                alertController.AddAction(UIAlertAction.Create(oneLayerName, UIAlertActionStyle.Default, action => AddLayerToMap(oneLayerName)));
            }

            // Add a choice to cancel.
            alertController.AddAction(UIAlertAction.Create("Cancel", UIAlertActionStyle.Cancel, action => Console.WriteLine("Canceled")));

            // Required for iPad - You must specify a source for the Action Sheet since it is displayed as a popover.
            UIPopoverPresentationController presentationPopover = alertController.PopoverPresentationController;
            if (presentationPopover != null)
            {
                presentationPopover.BarButtonItem = (UIBarButtonItem)sender;
                presentationPopover.PermittedArrowDirections = UIPopoverArrowDirection.Down;
            }

            // Display the list of layers to add to the map.
            PresentViewController(alertController, true, null);
        }

        private void AddLayerToMap(string layerName)
        {
            // This function finds the actual layer in the dictionary based upon the user selection and add it to the map
            // Then the human-readable layer name is removed from the _layersNotInMap and added to the _layersInMap.

            // Ensure there is a valid selection.
            if (!String.IsNullOrWhiteSpace(layerName))
            {
                // Get the layer from the dictionary (it could be either a RasterLayer
                // or a FeatureLayer - both inherit from the abstract/base Layer class).
                Layer layer = _nameToLayerDictionary[layerName];

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

                // Remove the human-readable layer name from the collection of layers not in the map.
                _layersNotInMap.Remove(layerName);

                // Add the human-readable layer name to the collection of layers in the map.
                _layersInMap.Add(layerName);
            }
        }

        private void RemoveLayerFromMap_Clicked(object sender, EventArgs e)
        {
            // Create a new Alert Controller.
            UIAlertController layersActionSheet = UIAlertController.Create(null, "Remove a layer from the map", UIAlertControllerStyle.ActionSheet);

            // Add actions to remove a layer from the map.
            foreach (string oneLayerName in _layersInMap)
            {
                layersActionSheet.AddAction(UIAlertAction.Create(oneLayerName, UIAlertActionStyle.Default, action => RemoveLayerFromMap(oneLayerName)));
            }

            // Add a choice to cancel.
            layersActionSheet.AddAction(UIAlertAction.Create("Cancel", UIAlertActionStyle.Cancel, action => Console.WriteLine("Canceled")));

            // Required for iPad - You must specify a source for the Action Sheet since it is displayed as a popover.
            UIPopoverPresentationController presentationPopover = layersActionSheet.PopoverPresentationController;
            if (presentationPopover != null)
            {
                presentationPopover.BarButtonItem = (UIBarButtonItem)sender;
                presentationPopover.PermittedArrowDirections = UIPopoverArrowDirection.Down;
            }

            // Display the list of layers to add/remove.
            PresentViewController(layersActionSheet, true, null);
        }

        private void RemoveLayerFromMap(string layerName)
        {
            // This function finds the actual layer in the dictionary based upon the user selection and add it to the map
            // Then the human-readable layer name is removed from the _layersInMap andadded to the _layersNotInMap.

            // Ensure there is a valid selection.
            if (!String.IsNullOrEmpty(layerName))
            {
                // Get the layer from the dictionary (it could be either a RasterLayer
                // or a FeatureLayer - both inherit from the abstract/base Layer class).
                Layer layer = _nameToLayerDictionary[layerName];

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

                // Remove the human-readable layer name from the collection of layers in the map.
                _layersInMap.Remove(layerName);

                // Add the human-readable layer name to the collection of layers not in the map.
                _layersNotInMap.Add(layerName);
            }
        }

        public override void ViewDidLoad()
        {
            base.ViewDidLoad();
            Initialize();
        }

        public override void LoadView()
        {
            // Create the views.
            View = new UIView() { BackgroundColor = ApplicationTheme.BackgroundColor };

            _myMapView = new MapView();
            _myMapView.TranslatesAutoresizingMaskIntoConstraints = false;

            // Add buttons.
            _addLayerButton = new UIBarButtonItem();
            _addLayerButton.Title = "Add layer";
            _addLayerButton.Enabled = false;

            _removeLayerButton = new UIBarButtonItem();
            _removeLayerButton.Title = "Remove layer";
            _removeLayerButton.Enabled = false;

            // Add the buttons to a toolbar.
            UIToolbar toolbar = new UIToolbar();
            toolbar.TranslatesAutoresizingMaskIntoConstraints = false;
            toolbar.Items = new[]
            {
                _addLayerButton,
                new UIBarButtonItem(UIBarButtonSystemItem.FlexibleSpace),
                _removeLayerButton
            };

            // Add the views.
            View.AddSubviews(_myMapView, toolbar);

            // Lay out the views.
            NSLayoutConstraint.ActivateConstraints(new[]
            {
                _myMapView.TopAnchor.ConstraintEqualTo(View.SafeAreaLayoutGuide.TopAnchor),
                _myMapView.LeadingAnchor.ConstraintEqualTo(View.LeadingAnchor),
                _myMapView.TrailingAnchor.ConstraintEqualTo(View.TrailingAnchor),
                _myMapView.BottomAnchor.ConstraintEqualTo(toolbar.TopAnchor),

                toolbar.LeadingAnchor.ConstraintEqualTo(View.LeadingAnchor),
                toolbar.TrailingAnchor.ConstraintEqualTo(View.TrailingAnchor),
                toolbar.BottomAnchor.ConstraintEqualTo(View.SafeAreaLayoutGuide.BottomAnchor)
            });
        }

        public override void ViewWillAppear(bool animated)
        {
            base.ViewWillAppear(animated);

            // Subscribe to events.
            _addLayerButton.Clicked += AddLayerToMap_Clicked;
            _removeLayerButton.Clicked += RemoveLayerFromMap_Clicked;
        }

        public override void ViewDidDisappear(bool animated)
        {
            base.ViewDidDisappear(animated);

            // Unsubscribe from events, per best practice.
            _addLayerButton.Clicked -= AddLayerToMap_Clicked;
            _removeLayerButton.Clicked -= RemoveLayerFromMap_Clicked;
        }
    }
}