Google map Geocoder And MoveToRegion not working

Question

I' have a very strange issue with Xamarin.Forms.Maps. I'm trying to implement a page with a map that get current location and move to region at page start.

All is working fine in IOS, but in Android, Geocoder & MoveToRegion are not working at all. Only the map is displayed.

I retrieve the location correctly (Long & Lat ) in the emulators & device. MoveToRegion do nothing & GetAddressesForPositionAsync retrive nothing.

Here the information in my manifest :

<meta-data android:name="com.google.android.maps.v2.API_KEY" android:value="mykey" />
        <meta-data android:name="com.google.android.gms.version" android:value="@integer/google_play_services_version" />

<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="com.google.android.providers.gsf.permission.READ_GSERVICES" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_LOCATION_EXTRA_COMMANDS" />
<uses-permission android:name="android.permission.ACCESS_MOCK_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />

Here the code :

map.MoveToRegion(MapSpan.FromCenterAndRadius(
                new Xamarin.Forms.Maps.Position(coordinates.Lat.Value, coordinates.Lng.Value), Distance.FromMiles(1))
            );

        var possibleAddresses = await locator.GetAddressesForPositionAsync(position);

I tried in Genymotion, Emulator from AVD. I'm not able to test in real device ( The deployment fail in my tablet )

Edit :

global::Xamarin.Forms.Forms.Init(this, bundle);

Was correctly set but still not working.

I force geocoder usage and it thrown this error :

[MonoDroid] UNHANDLED EXCEPTION:
[MonoDroid] Java.IO.IOException: grpc failed
[MonoDroid]   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw () [0x0000c] in <896ad1d315ca4ba7b117efb8dacaedcf>:0 
[MonoDroid]   at Java.Interop.JniEnvironment+InstanceMethods.CallObjectMethod (Java.Interop.JniObjectReference instance, Java.Interop.JniMethodInfo method, Java.Interop.JniArgumentValue* args) [0x00069] in <6cd960837cc24c26bab2a0a29b597627>:0 
[MonoDroid]   at Java.Interop.JniPeerMembers+JniInstanceMethods.InvokeAbstractObjectMethod (System.String encodedMember, Java.Interop.IJavaPeerable self, Java.Interop.JniArgumentValue* parameters) [0x00014] in <6cd960837cc24c26bab2a0a29b597627>:0 
[MonoDroid]   at Android.Locations.Geocoder.GetFromLocationName (System.String locationName, System.Int32 maxResults) [0x0003c] in <d278c06ad5684d6882c743a94a93ebc2>:0 
[MonoDroid]   at Android.Locations.Geocoder+<>c__DisplayClass17_0.<GetFromLocationNameAsync>b__0 () [0x00000] in <d278c06ad5684d6882c743a94a93ebc2>:0 
[MonoDroid]   at System.Threading.Tasks.Task`1[TResult].InnerInvoke () [0x0000f] in <896ad1d315ca4ba7b117efb8dacaedcf>:0 
[MonoDroid]   at System.Threading.Tasks.Task.Execute () [0x00010] in <896ad1d315ca4ba7b117efb8dacaedcf>:0 
[MonoDroid] --- End of stack trace from previous location where exception was thrown ---
[MonoDroid]   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw () [0x0000c] in <896ad1d315ca4ba7b117efb8dacaedcf>:0 
[MonoDroid]   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess (System.Threading.Tasks.Task task) [0x0003e] in <896ad1d315ca4ba7b117efb8dacaedcf>:0 
[MonoDroid]   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification (System.Threading.Tasks.Task task) [0x00028] in <896ad1d315ca4ba7b117efb8dacaedcf>:0 
[MonoDroid]   at System.Runtime.CompilerServices.TaskAwaiter.ValidateEnd (System.Threading.Tasks.Task task) [0x00008] in <896ad1d315ca4ba7b117efb8dacaedcf>:0 
[MonoDroid]   at System.Runtime.CompilerServices.TaskAwaiter`1[TResult].GetResult () [0x00000] in <896ad1d315ca4ba7b117efb8dacaedcf>:0 
[MonoDroid]   at Xamarin.Forms.Maps.Android.GeocoderBackend+<GetPositionsForAddressAsync>d__1.MoveNext () [0x0006b] in <39c694c022be4f7b8a39897d372b2d00>:0 
[MonoDroid] --- End of stack trace from previous location where exception was thrown ---
[MonoDroid]   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw () [0x0000c] in <896ad1d315ca4ba7b117efb8dacaedcf>:0 
[MonoDroid]   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess (System.Threading.Tasks.Task task) [0x0003e] in <896ad1d315ca4ba7b117efb8dacaedcf>:0 
[MonoDroid]   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification (System.Threading.Tasks.Task task) [0x00028] in <896ad1d315ca4ba7b117efb8dacaedcf>:0 
[MonoDroid]   at System.Runtime.CompilerServices.TaskAwaiter.ValidateEnd (System.Threading.Tasks.Task task) [0x00008] in <896ad1d315ca4ba7b117efb8dacaedcf>:0 
[MonoDroid]   at System.Runtime.CompilerServices.TaskAwaiter`1[TResult].GetResult () [0x00000] in <896ad1d315ca4ba7b117efb8dacaedcf>:0 
[MonoDroid]   at Picaplant.Views.GeolocationPage+<HandleAdressCompleted>d__8.MoveNext () [0x00047] in /Users/OrcusZ/Documents/AutoEntrepreneur/Picaplant/Source/Picaplant/Views/GeolocationPage.xaml.cs:158 
[MonoDroid] --- End of stack trace from previous location where exception was thrown ---
[MonoDroid]   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw () [0x0000c] in <896ad1d315ca4ba7b117efb8dacaedcf>:0 
[MonoDroid]   at System.Runtime.CompilerServices.AsyncMethodBuilderCore+<>c.<ThrowAsync>b__6_0 (System.Object state) [0x00000] in <896ad1d315ca4ba7b117efb8dacaedcf>:0 
[MonoDroid]   at Android.App.SyncContext+<>c__DisplayClass2_0.<Post>b__0 () [0x00000] in <d278c06ad5684d6882c743a94a93ebc2>:0 
[MonoDroid]   at Java.Lang.Thread+RunnableImplementor.Run () [0x00008] in <d278c06ad5684d6882c743a94a93ebc2>:0 
[MonoDroid]   at Java.Lang.IRunnableInvoker.n_Run (System.IntPtr jnienv, System.IntPtr native__this) [0x00008] in <d278c06ad5684d6882c743a94a93ebc2>:0 
[MonoDroid]   at (wrapper dynamic-method) System.Object:6621ff63-14b8-4291-a222-45bff630bddc (intptr,intptr)
[MonoDroid]   --- End of managed Java.IO.IOException stack trace ---
[MonoDroid] java.io.IOException: grpc failed
[MonoDroid]     at android.location.Geocoder.getFromLocationName(Geocoder.java:178)
[MonoDroid] 

EDIT 2 :

Same error with Xamarin Form Working with maps sample

Any idea ?

Answer 1

Here's a working cross-platform sample app. It runs in a KitKat 4.4 API Level 19 emulator and also in a Samsung Android device. We also present a custom Geocoder implementation using HTTP requests given that the standard one works fine for an actual Android device but returns an empty response for the emulator.

XAML:

<?xml version="1.0" encoding="utf-8" ?>
<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             xmlns:Maps="clr-namespace:Xamarin.Forms.Maps;assembly=Xamarin.Forms.Maps.dll"
             xmlns:local="clr-namespace:App20"
             x:Class="App20.MainPage">
    <ContentPage.Content>
        <Grid>
            <Grid.RowDefinitions>
                <RowDefinition Height="8*"></RowDefinition>
                <RowDefinition Height="4*"></RowDefinition>
                <RowDefinition Height="*"></RowDefinition>
                <RowDefinition Height="*"></RowDefinition>
            </Grid.RowDefinitions>

            <Maps:Map x:Name="map1" Grid.Row="0"></Maps:Map>
            <ListView ItemsSource="{Binding AddressList}" Grid.Row="1" />
            <Button Text="Move To Region" Grid.Row="2" Clicked="Button_Clicked_Move"></Button>
            <Button Text="Get Address" Grid.Row="3" Clicked="Button_Clicked_Address"></Button>
        </Grid>
    </ContentPage.Content>
</ContentPage>

CS:

public partial class MainPage : ContentPage
{
    MyViewModel vm;

    public MainPage()
    {
        InitializeComponent();

        vm = new MyViewModel();
        BindingContext = vm;
    }

    private void Button_Clicked_Move(object sender, EventArgs e)
    {
        map1.MoveToRegion(MapSpan.FromCenterAndRadius(
            new Position(vm.Lat, vm.Lon), Distance.FromMiles(vm.Distance)));
    }

    private async void Button_Clicked_Address(object sender, EventArgs e)
    {
        Geocoder gc = new Geocoder();

        var list = await gc.GetAddressesForPositionAsync(new Position(vm.Lat, vm.Lon));

        if (list.Count() > 0)
        {
            foreach (string s in list)
                vm.AddressList.Add(s);
        }
        else
        {
            MyGeocoder mgc = new MyGeocoder();

            var mylist = await mgc.GetAddressesForPositionAsync(vm.Lat, vm.Lon, vm.Key);

            foreach (string s in mylist)
                vm.AddressList.Add(s);
        }
    }
}

View Model:

public class MyViewModel
{
    public string Key { get; }
    public double Lat { get; set; }
    public double Lon { get; set; }
    public double Distance { get; set; }
    public ObservableCollection<string> AddressList { get; set; }

    public MyViewModel()
    {
        Lat = 40.706501;
        Lon = -74.011340;
        Distance = 0.5;
        Key = "YOUR_API_KEY";
        AddressList = new ObservableCollection<string>();
    }
}

Custom Geocoder:

public class MyGeocoder
{
    public async Task<IEnumerable<string>> GetAddressesForPositionAsync(double lat, double lon, string key)
    {
        HttpClient client = new HttpClient();

        var request = string.Format(@"https://maps.googleapis.com/maps/api/geocode/json?latlng={0},{1}&key={2}", lat, lon, key);

        var json = await client.GetStringAsync(request);

        var result = JObject.Parse(json)["results"];

        List<string> list = new List<string>();

        foreach (JToken jt in result)
            list.Add((string)jt["formatted_address"]);

        return list.AsEnumerable<string>();
    }
}