Custom annotation view in Google Maps SDK

I don’t know about y’all, but I find Google’s rendered UIView info windows to be a bit restricting. Using SMCalloutView and Ryan Maxwell’s example project, it’s possible to present more interactive views.

This works on Google Maps SDK v1.8.1, as of 2014-June-10.

First, do some set up:

#import <SMCalloutView/SMCalloutView.h>

static const CGFloat CalloutYOffset = 10.0f;

@interface ViewController ()
@property (strong, nonatomic) SMCalloutView *calloutView;
@property (strong, nonatomic) UIView *emptyCalloutView;
@end

Initialize SMCalloutView, add a button to it, then create an empty UIView:

- (void)viewDidLoad
{
    /* all your other view init, settings, etc... */

    self.calloutView = [[SMCalloutView alloc] init];
    self.calloutView.hidden = YES;

    UIButton *button = [UIButton buttonWithType:UIButtonTypeDetailDisclosure];
    [button addTarget:self
               action:@selector(calloutAccessoryButtonTapped:)
     forControlEvents:UIControlEventTouchUpInside];
    self.calloutView.rightAccessoryView = button;

    self.emptyCalloutView = [[UIView alloc] initWithFrame:CGRectZero];
}

We have to draw that empty UIView to satisfy the Maps SDK, but the view we will display is SMCalloutView. I also set a reuseable vertical offset for the callout view.

Add delegate methods to handle info window calls:

#pragma mark - GMSMapViewDelegate

- (UIView *)mapView:(GMSMapView *)mapView markerInfoWindow:(GMSMarker *)marker {
    CLLocationCoordinate2D anchor = marker.position;

    CGPoint point = [mapView.projection pointForCoordinate:anchor];

    self.calloutView.title = marker.title;

    self.calloutView.calloutOffset = CGPointMake(0, -CalloutYOffset);

    self.calloutView.hidden = NO;

    CGRect calloutRect = CGRectZero;
    calloutRect.origin = point;
    calloutRect.size = CGSizeZero;

    [self.calloutView presentCalloutFromRect:calloutRect
                                      inView:mapView
                           constrainedToView:mapView
                                    animated:YES];

    return self.emptyCalloutView;
}

- (void)mapView:(GMSMapView *)pMapView didChangeCameraPosition:(GMSCameraPosition *)position {
    /* move callout with map drag */
    if (pMapView.selectedMarker != nil && !self.calloutView.hidden) {
        CLLocationCoordinate2D anchor = [pMapView.selectedMarker position];

        CGPoint arrowPt = self.calloutView.backgroundView.arrowPoint;

        CGPoint pt = [pMapView.projection pointForCoordinate:anchor];
        pt.x -= arrowPt.x;
        pt.y -= arrowPt.y + CalloutYOffset;

        self.calloutView.frame = (CGRect) {.origin = pt, .size = self.calloutView.frame.size };
    } else {
        self.calloutView.hidden = YES;
    }
}

- (void)mapView:(GMSMapView *)mapView didTapAtCoordinate:(CLLocationCoordinate2D)coordinate {
    self.calloutView.hidden = YES;
}

- (BOOL)mapView:(GMSMapView *)mapView didTapMarker:(GMSMarker *)marker {
    /* don't move map camera to center marker on tap */
    mapView.selectedMarker = marker;
    return YES;
}

Handle touches on the callout button, here using an alert view with marker title and snippet:

- (void)calloutAccessoryButtonTapped:(id)sender {
    if (mapView_.selectedMarker) {
        GMSMarker *marker = mapView_.selectedMarker;
        //NSDictionary *userData = marker.userData;

        UIAlertView *alertView = [[UIAlertView alloc] initWithTitle:marker.title
                                                            message:marker.snippet
                                                           delegate:nil
                                                  cancelButtonTitle:@"OK"
                                                  otherButtonTitles:nil];
        [alertView show];
    }
}

Obviously, make sure your ViewController(.h) listens to GMSMapViewDelegate:

@interface ViewController : UIViewController <GMSMapViewDelegate>

And that should basically work. For a complete xcode project, see the aforementioned example from Ryan Maxwell.