GoogleMaps Framework Reference

AI-generated Key Takeaways

• GMSOverlay is an abstract class representing an overlay on a GMSMapView, and concrete types like GMSMarker, GMSPolyline, and GMSPolygon should be used instead of direct instantiation.

• It has properties like title for a short description, map to link with the map view, and tappable to enable tap notifications.

• zIndex controls the drawing order of overlays, with markers always drawn above non-marker overlays regardless of zIndex value.

• The userData property allows attaching arbitrary data to the overlay, but avoid strong references to Maps objects to prevent retain cycles.

GMSOverlay

@interface GMSOverlay : NSObject <NSCopying>

GMSOverlay is an abstract class that represents some overlay that may be attached to a specific GMSMapView. It may not be instantiated directly; instead, instances of concrete overlay types should be created directly (such as GMSMarker, GMSPolyline, and GMSPolygon).

This supports the NSCopying protocol; [overlay_ copy] will return a copy of the overlay type, but with map set to nil.

• title

  Title, a short description of the overlay. Some overlays, such as markers, will display the title on the map. The title is also the default accessibility text.

  Declaration

  Swift

  var title: String? { get set }

  Objective-C

  @property (nonatomic, copy, nullable) NSString *title;

• map

  The map this overlay is on. Setting this property will add the overlay to the map. Setting it to nil removes this overlay from the map. An overlay may be active on at most one map at any given time.

  Declaration

  Swift

  weak var map: GMSMapView? { get set }

  Objective-C

  @property (nonatomic, weak, nullable) GMSMapView *map;

• tappable

  If this overlay should cause tap notifications. Some overlays, such as markers, will default to being tappable.

  Declaration

  Swift

  var isTappable: Bool { get set }

  Objective-C

  @property (nonatomic, getter=isTappable) BOOL tappable;

• zIndex

  Higher zIndex value overlays will be drawn on top of lower zIndex value tile layers and overlays. Equal values result in undefined draw ordering. Markers are an exception that regardless of zIndex, they will always be drawn above tile layers and other non-marker overlays; they are effectively considered to be in a separate z-index group compared to other overlays.

  Declaration

  Swift

  var zIndex: Int32 { get set }

  Objective-C

  @property (nonatomic) int zIndex;

• userData

  Overlay data. You can use this property to associate an arbitrary object with this overlay. Google Maps SDK for iOS neither reads nor writes this property.

  Note that userData should not hold any strong references to any Maps objects, otherwise a retain cycle may be created (preventing objects from being released).

  Declaration

  Swift

  var userData: Any? { get set }

  Objective-C

  @property (nonatomic, nullable) id userData;