Format coordinates

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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 Android.App;
using Android.OS;
using Android.Widget;
using Esri.ArcGISRuntime.Geometry;
using Esri.ArcGISRuntime.Mapping;
using Esri.ArcGISRuntime.Symbology;
using Esri.ArcGISRuntime.UI;
using Esri.ArcGISRuntime.UI.Controls;
using System;
using System.Drawing;

namespace ArcGISRuntime.Samples.FormatCoordinates
{
    [Activity (ConfigurationChanges=Android.Content.PM.ConfigChanges.Orientation | Android.Content.PM.ConfigChanges.ScreenSize)]
    [ArcGISRuntime.Samples.Shared.Attributes.Sample(
        name: "Format coordinates",
        category: "Geometry",
        description: "Format coordinates in a variety of common notations.",
        instructions: "Tap on the map to see a callout with the clicked location's coordinate formatted in 4 different ways. You can also put a coordinate string in any of these formats in the text field. Hit Enter and the coordinate string will be parsed to a map location which the callout will move to.",
        tags: new[] { "USNG", "UTM", "convert", "coordinate", "decimal degrees", "degree minutes seconds", "format", "latitude", "longitude" })]
    public class FormatCoordinates : Activity
    {
        // Hold a reference to the map view
        private MapView _myMapView;

        private EditText _DecimalDegreesEditText;
        private EditText _DmsEditText;
        private EditText _UtmEditText;
        private EditText _UsngEditText;

        // Hold last edited field
        private EditText _lastEdited;

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

            Title = "Format coordinates";

            // Create the UI, setup the control references and execute initialization
            CreateLayout();
            Initialize();
        }

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

            // Add the graphics overlay to the map
            _myMapView.GraphicsOverlays.Add(new GraphicsOverlay());

            // Create the starting point
            MapPoint startingPoint = new MapPoint(0, 0, SpatialReferences.WebMercator);

            // Update the UI with the initial point
            UpdateUIFromMapPoint(startingPoint);

            // Subscribe to map tap events to enable tapping on map to update coordinates
            _myMapView.GeoViewTapped += (sender, args) => { UpdateUIFromMapPoint(args.Location); };
        }

        private void InputTextChanged(object sender, EventArgs e)
        {
            // Keep track of the last edited field
            _lastEdited = (EditText)sender;
        }

        private void RecalculateFields(object sender, EventArgs e)
        {
            // Hold the entered point
            MapPoint enteredPoint = null;

            // Set a default last edited field to prevent NullReferenceException
            if (_lastEdited == null)
            {
                _lastEdited = _DecimalDegreesEditText;
            }

            // Update the point based on which text sent the event
            try
            {
                switch (_lastEdited.Hint)
                {
                    case "Decimal Degrees":
                    case "Degrees, Minutes, Seconds":
                        enteredPoint =
                            CoordinateFormatter.FromLatitudeLongitude(_lastEdited.Text, _myMapView.SpatialReference);
                        break;

                    case "UTM":
                        enteredPoint =
                            CoordinateFormatter.FromUtm(_lastEdited.Text, _myMapView.SpatialReference, UtmConversionMode.NorthSouthIndicators);
                        break;

                    case "USNG":
                        enteredPoint =
                            CoordinateFormatter.FromUsng(_lastEdited.Text, _myMapView.SpatialReference);
                        break;
                }
            }
            catch (Exception ex)
            {
                // The coordinate is malformed, warn and return
                // Display the message to the user
                AlertDialog.Builder builder = new AlertDialog.Builder(this);
                builder.SetMessage(ex.Message).SetTitle("Invalid Format").Show();
                return;
            }

            // Update the UI from the MapPoint
            UpdateUIFromMapPoint(enteredPoint);
        }

        private void UpdateUIFromMapPoint(MapPoint selectedPoint)
        {
            // Clear event subscriptions - prevents an infinite loop
            _UtmEditText.TextChanged -= InputTextChanged;
            _DmsEditText.TextChanged -= InputTextChanged;
            _DecimalDegreesEditText.TextChanged -= InputTextChanged;
            _UsngEditText.TextChanged -= InputTextChanged;

            try
            {
                // Check if the selected point can be formatted into coordinates.
                CoordinateFormatter.ToLatitudeLongitude(selectedPoint, LatitudeLongitudeFormat.DecimalDegrees, 0);
            }
            catch (Exception e)
            {
                // Check if the excpetion is because the coordinates are out of range.
                if (e.Message == "Invalid argument: coordinates are out of range")
                {
                    // Set all of the text fields to contain the error message.
                    _DecimalDegreesEditText.Text = "Coordinates are out of range";
                    _DmsEditText.Text = "Coordinates are out of range";
                    _UtmEditText.Text = "Coordinates are out of range";
                    _UsngEditText.Text = "Coordinates are out of range";

                    // Clear the selectionss symbol.
                    _myMapView.GraphicsOverlays[0].Graphics.Clear();
                }
                // Restore event subscriptions.
                _UtmEditText.TextChanged += InputTextChanged;
                _DmsEditText.TextChanged += InputTextChanged;
                _DecimalDegreesEditText.TextChanged += InputTextChanged;
                _UsngEditText.TextChanged += InputTextChanged;
                return;
            }

            // Update the decimal degrees text
            _DecimalDegreesEditText.Text =
                CoordinateFormatter.ToLatitudeLongitude(selectedPoint, LatitudeLongitudeFormat.DecimalDegrees, 4);

            // Update the degrees, minutes, seconds text
            _DmsEditText.Text = CoordinateFormatter.ToLatitudeLongitude(selectedPoint,
                LatitudeLongitudeFormat.DegreesMinutesSeconds, 1);

            // Update the UTM text
            _UtmEditText.Text = CoordinateFormatter.ToUtm(selectedPoint, UtmConversionMode.NorthSouthIndicators, true);

            // Update the USNG text
            _UsngEditText.Text = CoordinateFormatter.ToUsng(selectedPoint, 4, true);

            // Clear existing graphics overlays
            _myMapView.GraphicsOverlays[0].Graphics.Clear();

            // Create a symbol to symbolize the point
            SimpleMarkerSymbol symbol = new SimpleMarkerSymbol(SimpleMarkerSymbolStyle.X, Color.Yellow, 20);

            // Create the graphic
            Graphic symbolGraphic = new Graphic(selectedPoint, symbol);

            // Add the graphic to the graphics overlay
            _myMapView.GraphicsOverlays[0].Graphics.Add(symbolGraphic);

            // Restore event subscriptions
            _UtmEditText.TextChanged += InputTextChanged;
            _DmsEditText.TextChanged += InputTextChanged;
            _DecimalDegreesEditText.TextChanged += InputTextChanged;
            _UsngEditText.TextChanged += InputTextChanged;
        }

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

            // Help Label
            TextView helpLabel = new TextView(this) { Text = "Edit the coordinates or tap the map to see conversions.\n\n" };
            layout.AddView(helpLabel);

            // Decimal Degrees
            _DecimalDegreesEditText = new EditText(this) { Hint = "Decimal Degrees" };
            TextView ddTextLabel = new TextView(this) { Text = "Decimal Degrees:" };
            layout.AddView(ddTextLabel);
            layout.AddView(_DecimalDegreesEditText);

            // Degrees, Minutes, Seconds
            _DmsEditText = new EditText(this) { Hint = "Degrees, Minutes, Seconds" };
            TextView dmsTextLabel = new TextView(this) { Text = "Degrees, Minutes, Seconds: " };
            layout.AddView(dmsTextLabel);
            layout.AddView(_DmsEditText);

            // UTM
            _UtmEditText = new EditText(this) { Hint = "UTM" };
            TextView utmTextLabel = new TextView(this) { Text = "UTM:" };
            layout.AddView(utmTextLabel);
            layout.AddView(_UtmEditText);

            // USNG
            _UsngEditText = new EditText(this) { Hint = "USNG" };
            TextView usngTextLabel = new TextView(this) { Text = "USNG" };
            layout.AddView(usngTextLabel);
            layout.AddView(_UsngEditText);

            // Button to allow for recalculating
            Button recalculateButton = new Button(this) { Text = "Recalculate" };
            recalculateButton.Click += RecalculateFields;
            layout.AddView(recalculateButton);

            // Add the map view to the layout
            _myMapView = new MapView(this);
            layout.AddView(_myMapView);

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