Feature layer events

Select platform: Android iOS JavaScript

This example shows map boundaries for GMSFeatureTypeLocality, and implements the delegate function that styles the clicked polygon. The result displays an info alert window with the event data.

A diagram showing a clicked boundary polygon map

Swift

class SampleViewController: UIViewController {

  private lazy var mapView: GMSMapView = GMSMapView(frame: .zero, mapID: GMSMapID(identifier: "YOUR_MAP_ID"), camera: GMSCameraPosition(latitude: 40, longitude: -80, zoom: 12))

  override func loadView() {
    view = mapView
    let style = FeatureStyle(fill: .orange.withAlphaComponent(0.5), stroke: .orange, strokeWidth: 2)
    mapView.featureLayer(of: .locality).style = { _ in style }
    mapView.delegate = self
  }
}

extension SampleViewController: GMSMapViewDelegate {
  func mapView(_ mapView: GMSMapView, didTap features: [Feature], in featureLayer: FeatureLayer<Feature>, atLocation: CLLocationCoordinate2D) {
    let toast = UIAlertController(title: "Clicked places", message: (features.compactMap { ($0 as? PlaceFeature)?.placeID }).joined(separator: ", "), preferredStyle: .alert)
    present(toast, animated: true, completion: nil)
  }
}

Objective-C

@interface SampleViewController: UIViewController <GMSMapViewDelegate>
@end

@implementation SampleViewController
- (void)loadView {
    GMSMapView *mapView = [GMSMapView mapWithFrame:CGRectZero mapID:[GMSMapID mapIDWithIdentifier:@"YOUR_MAP_ID"] camera:[GMSCameraPosition cameraWithLatitude:40 longitude:-80 zoom:12]];
    mapView.delegete = self;

    GMSFeatureStyle *style = [GMSFeatureStyle styleWithFillColor:[[UIColor orangeColor] colorWithAlphaComponent:0.5] strokeColor:[UIColor orangeColor] strokeWidth:2.0];
    [mapView featureLayerOfFeatureType:GMSFeatureTypeLocality].style = ^(GMSPlaceFeature *feature) { return style; };

    self.view = mapView;
}

- (void)mapView:(GMSMapView *)mapView didTapFeatures:(NSArray<id<GMSFeature>> *)features inFeatureLayer:(GMSFeatureLayer *)featureLayer atLocation:(CLLocationCoordinate2D)location {
  NSMutableArray<NSString *> *places = [NSMutableArray array];

  for (id<GMSFeature> feature in features) {
    if (![feature isKindOfClass:[GMSPlaceFeature class]]) { continue; }
    NSString *placeID = ((GMSPlaceFeature *)feature).placeID;
    [places addObject:placeID];
  }

  UIAlertController *toast = [UIAlertController alertControllerWithTitle:@"Clicked places" message:[places componentsJoinedByString:@", "] preferredStyle:UIAlertControllerStyleAlert];
  [self presentViewController:toast animated:YES completion:nil];
}