Question

In Monodroid, I am trying to access GPS services. All I need is a location object.

this line thorws an error:

• _locationManager.RequestLocationUpdates(LocationManager.GpsProvider, 1000, 10, this);

Java.Lang.SecurityException

The stack trace says at Android.Runtime.JNIEnv.CallVoidMethod(IntPtr jobject, IntPtr jmethod, Android.Runtime.jValue[] params) [0x00000] in :0

I have the latest version of monodroid and I am running it on a Samsung Galaxy S II physical device.

I think it has something to do with the Manifest file – I suspect there is an attribute I am missing so that Monodroid can generate a manifest that tells the device I am using GPS services.

I know from http://docs.xamarin.com/android/advanced_topics/working_with_androidmanifest.xml that Monodroid generates it’s own AndroidManifest file using mandroid.exe. Now either I must modify the AndroidManifest.xml file myself or I must get mandroid to insert GPS things for me. Here’s the kicker: there is no ‘merge’ file as described by the link above – so I am left with doing it through mandroid.

So do I create and add a new file for mandroid to merge with?

Here is what I am doing:

...
using Android.App;
using Android.Content;
using Android.OS;
using Android.Runtime;
using Android.Views;
using Android.Widget;
using Android.Locations;
...

namespace mynamespace
{
    [Activity(Label = "My Activity")]  
    public class MainActivity : Activity, ILocationListener
    {
        ...
        #region Location Variables
        LocationManager _locationManager;
        #endregion

        protected override void OnCreate(Bundle bundle)
        {
            base.OnCreate(bundle);
            SetContentView(Resource.Layout.MainPage);

            ...
            #region Location Setup
            try
            {
                _locationManager = null;

                if (/*user says to use location services*/)
                {

                    _locationManager = (LocationManager)GetSystemService(Context.LocationService);
                    _locationManager.RequestLocationUpdates(LocationManager.GpsProvider, 1000, 10, this);
                }
            }
            catch (Exception ex)
            {
                _debug.Text = string.Format("{0} -- {1}",ex.Message,ex.StackTrace);
            }

            #endregion

            ...
        }

        #region Common Methods
        ...
        #endregion

        #region Events
        ...
        #endregion

        #region Location Services
        public void OnLocationChanged(Location location)
        {
            _debug.Text = string.Format("long: {0}, lat: {1}", location.Longitude, location.Latitude);
        }

        public void OnProviderDisabled(string provider)
        {
            //throw new NotImplementedException();
        }

        public void OnProviderEnabled(string provider)
        {            
            //throw new NotImplementedException();
        }

        public void OnStatusChanged(string provider, int status, Bundle extras)
        {
            //throw new NotImplementedException();
        }
        #endregion
    }
}

Answer 1

You app does not have permissions to access GPS. To solve this open context menu on project, select Properties-> Android Manifest. If there is no nothing click on the link “No AndroidMaifest.xml found. Click to add one.” Check permission to access GPS data – ACCESS_FINE_LOCATION. Save, rebuild, enjoy.