GMSPolygon doesn't work in iOS Google Maps app - ios

Question

I have this code below for my new iOS Google Maps app. I can create dynamic markers on the map as the user taps on the screen but the polygon shape between the markers does not gets drawn. Any ideas why is this happening?
- (void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view.
//Controls whether the My Location dot and accuracy circle is enabled.
CGFloat currentZoom = 14.0f;
self.mapView.myLocationEnabled = YES;
//adds type of map: kGMSTypeSatellite, kGMSTypeTerrain, kGMSTypeHybrid, kGMSTypeNormal
self.mapView.mapType = kGMSTypeHybrid;
//Shows the compass button on the map
self.mapView.settings.compassButton = YES;
//Shows the my location button on the map
self.mapView.settings.myLocationButton = YES;
//Sets the view controller to be the GMSMapView delegate
self.mapView.delegate = self;
GMSCameraPosition *manhattan = [GMSCameraPosition cameraWithLatitude:40.790278
longitude:-73.959722
zoom:14];
self.mapView.camera = manhattan;
}
//setting up zoom
-(void)ZoominOutMap:(CGFloat)level
{
self.mapView.delegate = self;
GMSCameraPosition *camera = [GMSCameraPosition cameraWithLatitude:40.790218 longitude:-73.959722
zoom:level];
self.mapView.camera = camera;
}
-(void)zoomInMapView:(id)sender
{
CGFloat currentZoom;
currentZoom = currentZoom + 1;
[self ZoominOutMap:currentZoom];
}
-(void) zoomOutMapView:(id)sender
{
CGFloat currentZoom;
currentZoom = currentZoom - 1;
[self ZoominOutMap:currentZoom];
}
- (void)mapView:(GMSMapView *)mapView didTapAtCoordinate:(CLLocationCoordinate2D)coordinate
{
NSLog(#"You tapped at %f,%f", coordinate.latitude, coordinate.longitude);
GMSMarker *marker = [[GMSMarker alloc] init];
//adds animation for adding marker
marker.appearAnimation = kGMSMarkerAnimationPop;
//draw marker on tapped position
marker.position = CLLocationCoordinate2DMake(coordinate.latitude,coordinate.longitude);
marker.map = _mapView;
//set color of marker and make them draggable
marker.icon = [GMSMarker markerImageWithColor:[UIColor blueColor]];
[marker setDraggable: YES];
// Create a rectangular path
GMSMutablePath *rect = [GMSMutablePath path];
[rect addCoordinate:CLLocationCoordinate2DMake(coordinate.latitude,coordinate.longitude)];
// Create the polygon, and assign it to the map.
GMSPolygon *polygon = [GMSPolygon polygonWithPath:rect];
polygon.fillColor = [UIColor colorWithRed:0.25 green:0 blue:0 alpha:0.05];
polygon.strokeColor = [UIColor blackColor];
polygon.strokeWidth = 2;
polygon.map = _mapView;
}

Answer 1

In your code you are not providing rectangular path. Add proper polygon coordinates to draw GMSPolygon
// Create a rectangular path
GMSMutablePath *rect = [GMSMutablePath path];
[rect addCoordinate:CLLocationCoordinate2DMake(37.36, -122.0)];
[rect addCoordinate:CLLocationCoordinate2DMake(37.45, -122.0)];
[rect addCoordinate:CLLocationCoordinate2DMake(37.45, -122.2)];
[rect addCoordinate:CLLocationCoordinate2DMake(37.36, -122.2)];
// Create the polygon, and assign it to the map.
GMSPolygon *polygon = [GMSPolygon polygonWithPath:rect];
polygon.fillColor = [UIColor colorWithRed:0.25 green:0 blue:0 alpha:0.05];
polygon.strokeColor = [UIColor blackColor];
polygon.strokeWidth = 2;
polygon.map = mapView;
Update:
Answer How to insert array values to draw polygon based on long/lat values - Google Maps iOS?

Answer 2

You have to cut this line from 'didTapAtCoordinate' of code and paste it in viewDidLoad
#GMSMutablePath *rect = [GMSMutablePath path];#
Then it will work