114 lines
3.5 KiB
C#
114 lines
3.5 KiB
C#
using System;
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using Xamarin.Forms;
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using Xamarin.Forms.Maps;
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using System.Diagnostics;
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namespace NightFlash
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{
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public class MapPage : ContentPage
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{
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Map map;
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public MapPage ()
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{
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map = new Map {
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IsShowingUser = true,
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HeightRequest = 100,
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WidthRequest = 960,
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VerticalOptions = LayoutOptions.FillAndExpand
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};
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// You can use MapSpan.FromCenterAndRadius
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// map.MoveToRegion (MapSpan.FromCenterAndRadius (
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// new Position (37, -122), Distance.FromMiles (0.3)));
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// or create a new MapSpan object directly
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map.MoveToRegion (new MapSpan (new Position (0,0), 360, 360) );
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// add the slider
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var slider = new Slider (1, 18, 1);
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slider.ValueChanged += (sender, e) => {
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var zoomLevel = e.NewValue; // between 1 and 18
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var latlongdegrees = 360 / (Math.Pow(2, zoomLevel));
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Debug.WriteLine(zoomLevel + " -> " + latlongdegrees);
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if (map.VisibleRegion != null)
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map.MoveToRegion(new MapSpan (map.VisibleRegion.Center, latlongdegrees, latlongdegrees));
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};
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// create map style buttons
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var street = new Button { Text = "Street" };
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var hybrid = new Button { Text = "Hybrid" };
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var satellite = new Button { Text = "Satellite" };
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street.Clicked += HandleClicked;
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hybrid.Clicked += HandleClicked;
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satellite.Clicked += HandleClicked;
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var segments = new StackLayout { Spacing = 30,
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HorizontalOptions = LayoutOptions.CenterAndExpand,
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Orientation = StackOrientation.Horizontal,
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Children = {street, hybrid, satellite}
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};
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// put the page together
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var stack = new StackLayout { Spacing = 0 };
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stack.Children.Add(map);
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stack.Children.Add (slider);
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stack.Children.Add (segments);
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Content = stack;
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// for debugging output only
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map.PropertyChanged += (sender, e) => {
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Debug.WriteLine(e.PropertyName + " just changed!");
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if (e.PropertyName == "VisibleRegion" && map.VisibleRegion != null)
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CalculateBoundingCoordinates (map.VisibleRegion);
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};
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}
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void HandleClicked (object sender, EventArgs e)
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{
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var b = sender as Button;
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switch (b.Text) {
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case "Street":
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map.MapType = MapType.Street;
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break;
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case "Hybrid":
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map.MapType = MapType.Hybrid;
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break;
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case "Satellite":
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map.MapType = MapType.Satellite;
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break;
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}
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}
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/// <summary>
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/// In response to this forum question http://forums.xamarin.com/discussion/22493/maps-visibleregion-bounds
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/// Useful if you need to send the bounds to a web service or otherwise calculate what
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/// pins might need to be drawn inside the currently visible viewport.
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/// </summary>
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static void CalculateBoundingCoordinates (MapSpan region)
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{
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// WARNING: I haven't tested the correctness of this exhaustively!
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var center = region.Center;
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var halfheightDegrees = region.LatitudeDegrees / 2;
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var halfwidthDegrees = region.LongitudeDegrees / 2;
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var left = center.Longitude - halfwidthDegrees;
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var right = center.Longitude + halfwidthDegrees;
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var top = center.Latitude + halfheightDegrees;
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var bottom = center.Latitude - halfheightDegrees;
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// Adjust for Internation Date Line (+/- 180 degrees longitude)
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if (left < -180) left = 180 + (180 + left);
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if (right > 180) right = (right - 180) - 180;
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// I don't wrap around north or south; I don't think the map control allows this anyway
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Debug.WriteLine ("Bounding box:");
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Debug.WriteLine (" " + top);
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Debug.WriteLine (" " + left + " " + right);
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Debug.WriteLine (" " + bottom);
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}
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}
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}
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