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c# openstreetmap xamarin mapsui

OpenStreetMap is not showing anymore using OsmSharp and Mapsui

发布于 2020-04-20 11:01:37

I'm still fairly new to Visual Studio/Xamarin but I had a simple OpenStreetMap sample running awhile ago for Android that did display a map but that doesn't seem to display map anymore though I haven't changed the code for this sample in awhile as far as I recall. I'm not sure if some Visual Studio/Xamarin or MacOS update might have caused it to not work anymore.

I'm using Visual Studio for Mac community 8.4.4 (build 91) on macOS Mojava 10.14.6 and the following Packages:

  • Mapsui 1.4.8
  • OsmSharp 6.2.0
  • Xamarin.Android.Support.Core.Utils 28.0.0.1
  • Xamarin.Android.Support.CustomTabs 28.0.0.1
  • Xamarin.Android.Support.Design 28.0.0.1
  • Xamarin.Essentials 1.2.0

My MainActivity.cs file contains the following code:

using System;
using Android.App;
using Android.OS;
using Android.Runtime;
using Android.Support.Design.Widget;
using Android.Support.V7.App;
using Android.Views;
using Android.Widget;
using Mapsui;
using Mapsui.Geometries;
using Mapsui.Projection;
using Mapsui.Styles;
using Mapsui.Utilities;
using Mapsui.UI.Android;
using Mapsui.Widgets.ScaleBar;
using Mapsui.Widgets.Zoom;
using Xamarin.Essentials;

namespace mvp_android
{
    [Activity(Label = "@string/app_name", Theme = "@style/AppTheme.NoActionBar", MainLauncher = true)]
    public class MainActivity : AppCompatActivity
    {
        protected override void OnCreate(Bundle savedInstanceState)
        {
            base.OnCreate(savedInstanceState);
            Xamarin.Essentials.Platform.Init(this, savedInstanceState);
            SetContentView(Resource.Layout.Main);

            var mapControl = FindViewById<MapControl>(Resource.Id.mapcontrol);
            var map = new Mapsui.Map();
            map.Layers.Add(OpenStreetMap.CreateTileLayer());
            map.Widgets.Add(
                new ZoomInOutWidget(map) {
                    HorizontalAlignment = Mapsui.Widgets.HorizontalAlignment.Left,
                    VerticalAlignment = Mapsui.Widgets.VerticalAlignment.Top,
                    Orientation = Mapsui.Widgets.Zoom.Orientation.Horizontal,
                }
            );
            var centerOfLondonOntario = new Point(-81.2497, 42.9837);
            map.NavigateTo(SphericalMercator.FromLonLat(centerOfLondonOntario.X, centerOfLondonOntario.Y));
            map.NavigateTo(map.Resolutions[9]);
            mapControl.Map = map;
        }

        public override bool OnCreateOptionsMenu(IMenu menu)
        {
            MenuInflater.Inflate(Resource.Menu.menu_main, menu);
            return true;
        }

        public override bool OnOptionsItemSelected(IMenuItem item)
        {
            int id = item.ItemId;
            if (id == Resource.Id.action_settings)
            {
                return true;
            }

            return base.OnOptionsItemSelected(item);
        }

        private void FabOnClick(object sender, EventArgs eventArgs)
        {
            View view = (View)sender;
            Snackbar.Make(view, "Replace with your own action", Snackbar.LengthLong)
                .SetAction("Action", (Android.Views.View.IOnClickListener)null).Show();
        }

        public override void OnRequestPermissionsResult(int requestCode, string[] permissions, [GeneratedEnum] Android.Content.PM.Permission[] grantResults)
        {
            Xamarin.Essentials.Platform.OnRequestPermissionsResult(requestCode, permissions, grantResults);

            base.OnRequestPermissionsResult(requestCode, permissions, grantResults);
        }
    }
}

And my Main.xml contains the following code:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent">
  <Mapsui.UI.Android.MapControl
           android:id="@+id/mapcontrol"
           android:layout_width="match_parent"
           android:layout_height="match_parent" />
</LinearLayout>

Originally, this sample showed the OpenStreetMap's map centering on the London, Ontario location with zoom in/out buttons, but now it just shows a white where the map should be, still shows the zoom in/out buttons and does display the (c)OpenStreetMap watermark.

What am I missing here?

Questioner
oosie
Viewed
54
pauldendulk 2020-02-13 21:18

The version of BruTile used in Mapsui 1.4.8 did not send the user-agent as part of it's request and at some point the openstreetmap server started blocking requests for this reason.

As a workaround you could create a custom ITileSource as described here by Matt Schneeberger: https://github.com/Mapsui/Mapsui/issues/668#issuecomment-497947690