private async Task DrawMapAsync(bool moveMap = true)
{
if (GMap == null)
{
return;
}
if (_eventLocation == null && _currentUserLocation == null)
{
return;
}
// Set callback to detect when map has finished loading
RunOnUiThread(() => { GMap.SetOnMapLoadedCallback(new MapLoadedCallback(Map.Id)); });
await Task.Run(() =>
{
// Calculate the map position and zoom/size
CameraUpdate cameraUpdate = null;
if (moveMap)
{
if (_currentUserLocation == null)
{
// Only event location available
cameraUpdate = CameraUpdateFactory.NewLatLngZoom(_eventLocation, Constants.DefaultResponseMapZoom);
}
else if (_eventLocation == null)
{
// Only user location available
cameraUpdate = CameraUpdateFactory.NewLatLngZoom(_currentUserLocation, Constants.DefaultResponseMapZoom);
}
else
{
// Both locations available
// get deltas between those locations
var latDelta = Math.Abs(_eventLocation.Latitude - _currentUserLocation.Latitude);
var longDelta = Math.Abs(_eventLocation.Longitude - _currentUserLocation.Longitude);
// get the boundaries of the map
var minLat = Math.Min(_eventLocation.Latitude, _currentUserLocation.Latitude) - latDelta / 4;
var maxLat = Math.Max(_eventLocation.Latitude, _currentUserLocation.Latitude) + latDelta / 4;
var minLong = Math.Min(_eventLocation.Longitude, _currentUserLocation.Longitude) - longDelta / 4;
var maxLong = Math.Max(_eventLocation.Longitude, _currentUserLocation.Longitude) + longDelta / 4;
LatLngBounds.Builder builder = new LatLngBounds.Builder();
builder.Include(new LatLng(minLat, minLong));
builder.Include(new LatLng(maxLat, maxLong));
// shouldn't need to include these but we'll include them just in case
builder.Include(new LatLng(_eventLocation.Latitude, _eventLocation.Longitude));
builder.Include(new LatLng(_currentUserLocation.Latitude, _currentUserLocation.Longitude));
LatLngBounds bounds = builder.Build();
cameraUpdate = CameraUpdateFactory.NewLatLngBounds(bounds, 0);
}
// Set the map position
RunOnUiThread(() => { GMap.MoveCamera(cameraUpdate); });
}
// Add a markers
RunOnUiThread(() => {
if (_eventLocation != null)
{
if (EventLocationMarker == null)
{
var markerOptions = new MarkerOptions();
markerOptions.SetPosition(_eventLocation);
if (_colorHue > -1)
{
var bmDescriptor = BitmapDescriptorFactory.DefaultMarker(_colorHue);
markerOptions.SetIcon(bmDescriptor);
}
EventLocationMarker = GMap.AddMarker(markerOptions);
}
else
{
var bmDescriptor = BitmapDescriptorFactory.DefaultMarker(_colorHue);
EventLocationMarker.SetIcon(bmDescriptor);
EventLocationMarker.Position = _eventLocation;
}
}
if (_currentUserLocation != null)
{
if (UserLocationMarker == null)
{
var markerOptions0 = new MarkerOptions();
markerOptions0.SetPosition(_currentUserLocation);
markerOptions0.SetIcon(UserLocationIcon);
markerOptions0.Anchor(0.5f, 0.5f);
UserLocationMarker = GMap.AddMarker(markerOptions0);
}
else
{
UserLocationMarker.Position = _currentUserLocation;
}
}
});
Map.OnResume();
RunOnUiThread(() => { Map.OnEnterAmbient(null); });
});
// Set the map type back to normal.
this.RunOnUiThread(() => { GMap.MapType = GoogleMap.MapTypeNormal; });
}
