MGLMapViewDelegate

@protocol MGLMapViewDelegate <NSObject>

The MGLMapViewDelegate protocol defines a set of optional methods that you can use to receive map-related update messages. Because many map operations require the MGLMapView class to load data asynchronously, the map view calls these methods to notify your application when specific operations complete. The map view also uses these methods to request information about annotations displayed on the map, such as the styles and interaction modes to apply to individual annotations.

  • Tells the delegate that the viewpoint depicted by the map view is about to change.

    This method is called whenever the currently displayed map camera will start changing for any reason.

    Declaration

    Objective-C

    - (void)mapView:(nonnull MGLMapView *)mapView
        regionWillChangeAnimated:(BOOL)animated;

    Swift

    optional func mapView(_ mapView: Any!, regionWillChangeAnimated animated: Any!)

    Parameters

    mapView

    The map view whose viewpoint will change.

    animated

    Whether the change will cause an animated effect on the map.

  • Tells the delegate that the viewpoint depicted by the map view is changing.

    This method is called as the currently displayed map camera changes as part of an animation, whether due to a user gesture or due to a call to a method such as -[MGLMapView setCamera:animated:]. During the animation, this method may be called many times to report updates to the viewpoint. Therefore, your implementation of this method should be as lightweight as possible to avoid affecting performance.

    Declaration

    Objective-C

    - (void)mapViewRegionIsChanging:(nonnull MGLMapView *)mapView;

    Swift

    optional func mapViewRegionIsChanging(_ mapView: Any!)

    Parameters

    mapView

    The map view whose viewpoint is changing.

  • Tells the delegate that the viewpoint depicted by the map view has finished changing.

    This method is called whenever the currently displayed map camera has finished changing, after any calls to -mapViewRegionIsChanging: due to animation.

    Declaration

    Objective-C

    - (void)mapView:(nonnull MGLMapView *)mapView
        regionDidChangeAnimated:(BOOL)animated;

    Swift

    optional func mapView(_ mapView: Any!, regionDidChangeAnimated animated: Any!)

    Parameters

    mapView

    The map view whose viewpoint has changed.

    animated

    Whether the change caused an animated effect on the map.

  • Tells the delegate that the map view will begin to load.

    This method is called whenever the map view starts loading, including when a new style has been set and the map must reload.

    Declaration

    Objective-C

    - (void)mapViewWillStartLoadingMap:(nonnull MGLMapView *)mapView;

    Swift

    optional func mapViewWillStartLoadingMap(_ mapView: Any!)

    Parameters

    mapView

    The map view that is starting to load.

  • Tells the delegate that the map view has finished loading.

    This method is called whenever the map view finishes loading, either after the initial load or after a style change has forced a reload.

    Declaration

    Objective-C

    - (void)mapViewDidFinishLoadingMap:(nonnull MGLMapView *)mapView;

    Swift

    optional func mapViewDidFinishLoadingMap(_ mapView: Any!)

    Parameters

    mapView

    The map view that has finished loading.

  • Tells the delegate that the map view was unable to load data needed for displaying the map.

    This method may be called for a variety of reasons, including a network connection failure or a failure to fetch the style from the server. You can use the given error message to notify the user that map data is unavailable.

    Declaration

    Objective-C

    - (void)mapViewDidFailLoadingMap:(nonnull MGLMapView *)mapView
                           withError:(nonnull NSError *)error;

    Swift

    optional func mapViewDidFailLoadingMap(_ mapView: Any!, withError error: Any!)

    Parameters

    mapView

    The map view that is unable to load the data.

    error

    The reason the data could not be loaded.

  • Tells the delegate that the map view is about to redraw.

    This method is called any time the map view needs to redraw due to a change in the viewpoint or style property transition. This method may be called very frequently, even moreso than -mapViewRegionIsChanging:. Therefore, your implementation of this method should be as lightweight as possible to avoid affecting performance.

    Declaration

    Objective-C

    - (void)mapViewWillStartRenderingFrame:(nonnull MGLMapView *)mapView;

    Swift

    optional func mapViewWillStartRenderingFrame(_ mapView: Any!)

    Parameters

    mapView

    The map view that is about to redraw.

  • Tells the delegate that the map view has just redrawn.

    This method is called any time the map view needs to redraw due to a change in the viewpoint or style property transition. This method may be called very frequently, even moreso than -mapViewRegionIsChanging:. Therefore, your implementation of this method should be as lightweight as possible to avoid affecting performance.

    Declaration

    Objective-C

    - (void)mapViewDidFinishRenderingFrame:(nonnull MGLMapView *)mapView
                             fullyRendered:(BOOL)fullyRendered;

    Swift

    optional func mapViewDidFinishRenderingFrame(_ mapView: Any!, fullyRendered: Any!)

    Parameters

    mapView

    The map view that has just redrawn.

  • Tells the delegate that the map view will begin tracking the user’s location.

    This method is called when the value of the showsUserLocation property changes to YES.

    Declaration

    Objective-C

    - (void)mapViewWillStartLocatingUser:(nonnull MGLMapView *)mapView;

    Swift

    optional func mapViewWillStartLocatingUser(_ mapView: Any!)

    Parameters

    mapView

    The map view that is tracking the user’s location.

  • Tells the delegate that the map view has stopped tracking the user’s location.

    This method is called when the value of the showsUserLocation property changes to NO.

    Declaration

    Objective-C

    - (void)mapViewDidStopLocatingUser:(nonnull MGLMapView *)mapView;

    Swift

    optional func mapViewDidStopLocatingUser(_ mapView: Any!)

    Parameters

    mapView

    The map view that is tracking the user’s location.

  • Tells the delegate that the location of the user was updated.

    While the showsUserLocation property is set to YES, this method is called whenever a new location update is received by the map view. This method is also called if the map view’s user tracking mode is set to MGLUserTrackingModeFollowWithHeading and the heading changes, or if it is set to MGLUserTrackingModeFollowWithCourse and the course changes.

    This method is not called if the application is currently running in the background. If you want to receive location updates while running in the background, you must use the Core Location framework.

    Declaration

    Objective-C

    - (void)mapView:(nonnull MGLMapView *)mapView
        didUpdateUserLocation:(nullable MGLUserLocation *)userLocation;

    Swift

    optional func mapView(_ mapView: Any!, didUpdateUserLocation userLocation: Any!)

    Parameters

    mapView

    The map view that is tracking the user’s location.

    userLocation

    The location object representing the user’s latest location. This property may be nil.

  • Tells the delegate that an attempt to locate the user’s position failed.

    Declaration

    Objective-C

    - (void)mapView:(nonnull MGLMapView *)mapView
        didFailToLocateUserWithError:(nonnull NSError *)error;

    Swift

    optional func mapView(_ mapView: Any!, didFailToLocateUserWithError error: Any!)

    Parameters

    mapView

    The map view that is tracking the user’s location.

    error

    An error object containing the reason why location tracking failed.

  • Tells the delegate that the map view’s user tracking mode has changed.

    This method is called after the map view asynchronously changes to reflect the new user tracking mode, for example by beginning to zoom or rotate.

    Declaration

    Objective-C

    - (void)mapView:(nonnull MGLMapView *)mapView
        didChangeUserTrackingMode:(MGLUserTrackingMode)mode
                         animated:(BOOL)animated;

    Swift

    optional func mapView(_ mapView: Any!, didChangeUserTrackingMode mode: Any!, animated: Any!)

    Parameters

    mapView

    The map view that changed its tracking mode.

    mode

    The new tracking mode.

    animated

    Whether the change caused an animated effect on the map.

  • Returns an annotation image object to mark the given point annotation object on the map.

    Implement this method to mark a point annotation with a static image. If you want to mark a particular point annotation with an annotation view instead, omit this method or have it return nil for that annotation, then implement -mapView:viewForAnnotation:.

    Static annotation images use less memory and draw more quickly than annotation views. On the other hand, annotation views are compatible with UIKit, Core Animation, and other Cocoa Touch frameworks.

    Declaration

    Objective-C

    - (nullable MGLAnnotationImage *)mapView:(nonnull MGLMapView *)mapView
                          imageForAnnotation:(nonnull id<MGLAnnotation>)annotation;

    Swift

    optional func mapView(_ mapView: Any!, imageForAnnotation annotation: Any!) -> Any!

    Parameters

    mapView

    The map view that requested the annotation image.

    annotation

    The object representing the annotation that is about to be displayed.

    Return Value

    The annotation image object to display for the given annotation or nil if you want to display the default marker image or an annotation view.

  • Returns the alpha value to use when rendering a shape annotation.

    A value of 0.0 results in a completely transparent shape. A value of 1.0, the default, results in a completely opaque shape.

    Declaration

    Objective-C

    - (CGFloat)mapView:(nonnull MGLMapView *)mapView
        alphaForShapeAnnotation:(nonnull MGLShape *)annotation;

    Swift

    optional func mapView(_ mapView: Any!, alphaForShapeAnnotation annotation: Any!) -> Any!

    Parameters

    mapView

    The map view rendering the shape annotation.

    annotation

    The annotation being rendered.

    Return Value

    An alpha value between 0 and 1.0.

  • Returns the color to use when rendering the outline of a shape annotation.

    The default stroke color is the map view’s tint color. If a pattern color is specified, the result is undefined.

    Declaration

    Objective-C

    - (nonnull UIColor *)mapView:(nonnull MGLMapView *)mapView
        strokeColorForShapeAnnotation:(nonnull MGLShape *)annotation;

    Swift

    optional func mapView(_ mapView: Any!, strokeColorForShapeAnnotation annotation: Any!) -> Any!

    Parameters

    mapView

    The map view rendering the shape annotation.

    annotation

    The annotation being rendered.

    Return Value

    A color to use for the shape outline.

  • Returns the color to use when rendering the fill of a polygon annotation.

    The default fill color is the map view’s tint color. If a pattern color is specified, the result is undefined.

    Declaration

    Objective-C

    - (nonnull UIColor *)mapView:(nonnull MGLMapView *)mapView
        fillColorForPolygonAnnotation:(nonnull MGLPolygon *)annotation;

    Swift

    optional func mapView(_ mapView: Any!, fillColorForPolygonAnnotation annotation: Any!) -> Any!

    Parameters

    mapView

    The map view rendering the polygon annotation.

    annotation

    The annotation being rendered.

    Return Value

    The polygon’s interior fill color.

  • Returns the line width in points to use when rendering the outline of a polyline annotation.

    By default, the polyline is outlined with a line 3.0 points wide.

    Declaration

    Objective-C

    - (CGFloat)mapView:(nonnull MGLMapView *)mapView
        lineWidthForPolylineAnnotation:(nonnull MGLPolyline *)annotation;

    Swift

    optional func mapView(_ mapView: Any!, lineWidthForPolylineAnnotation annotation: Any!) -> Any!

    Parameters

    mapView

    The map view rendering the polygon annotation.

    annotation

    The annotation being rendered.

    Return Value

    A line width for the polyline, measured in points.

  • Returns a view object to mark the given point annotation object on the map.

    Implement this method to mark a point annotation with a view object. If you want to mark a particular point annotation with a static image instead, omit this method or have it return nil for that annotation, then implement -mapView:imageForAnnotation: instead.

    Annotation views are compatible with UIKit, Core Animation, and other Cocoa Touch frameworks. On the other hand, static annotation images use less memory and draw more quickly than annotation views.

    The user location annotation view can also be customized via this method. When annotation is an instance of MGLUserLocation (or equal to the map view’s userLocation property), return an instance of MGLUserLocationAnnotationView (or a subclass thereof).

    Declaration

    Objective-C

    - (nullable MGLAnnotationView *)mapView:(nonnull MGLMapView *)mapView
                          viewForAnnotation:(nonnull id<MGLAnnotation>)annotation;

    Swift

    optional func mapView(_ mapView: Any!, viewForAnnotation annotation: Any!) -> Any!

    Parameters

    mapView

    The map view that requested the annotation view.

    annotation

    The object representing the annotation that is about to be displayed.

    Return Value

    The view object to display for the given annotation or nil if you want to display an annotation image instead.

  • Tells the delegate that one or more annotation views have been added and positioned on the map.

    This method is called just after the views are added to the map. You can implement this method to animate the addition of the annotation views.

    Declaration

    Objective-C

    - (void)mapView:(nonnull MGLMapView *)mapView
        didAddAnnotationViews:
            (nonnull NSArray<MGLAnnotationView *> *)annotationViews;

    Swift

    optional func mapView(_ mapView: Any!, didAddAnnotationViews annotationViews: Any!)

    Parameters

    mapView

    The map view to which the annotation views were added.

    annotationViews

    An array of MGLAnnotationView objects representing the views that were added.

  • Tells the delegate that one of its annotations was selected.

    You can use this method to track changes in the selection state of annotations.

    If the annotation is associated with an annotation view, you can also implement -mapView:didSelectAnnotationView:, which is called immediately after this method is called.

    Declaration

    Objective-C

    - (void)mapView:(nonnull MGLMapView *)mapView
        didSelectAnnotation:(nonnull id<MGLAnnotation>)annotation;

    Swift

    optional func mapView(_ mapView: Any!, didSelectAnnotation annotation: Any!)

    Parameters

    mapView

    The map view containing the annotation.

    annotation

    The annotation that was selected.

  • Tells the delegate that one of its annotations was deselected.

    You can use this method to track changes in the selection state of annotations.

    If the annotation is associated with an annotation view, you can also implement -mapView:didDeselectAnnotationView:, which is called immediately after this method is called.

    Declaration

    Objective-C

    - (void)mapView:(nonnull MGLMapView *)mapView
        didDeselectAnnotation:(nonnull id<MGLAnnotation>)annotation;

    Swift

    optional func mapView(_ mapView: Any!, didDeselectAnnotation annotation: Any!)

    Parameters

    mapView

    The map view containing the annotation.

    annotation

    The annotation that was deselected.

  • Tells the delegate that one of its annotation views was selected.

    You can use this method to track changes in the selection state of annotation views.

    This method is only called for annotation views. To track changes in the selection state of all annotations, including those associated with static annotation images, implement -mapView:didSelectAnnotation:, which is called immediately before this method is called.

    Declaration

    Objective-C

    - (void)mapView:(nonnull MGLMapView *)mapView
        didSelectAnnotationView:(nonnull MGLAnnotationView *)annotationView;

    Swift

    optional func mapView(_ mapView: Any!, didSelectAnnotationView annotationView: Any!)

    Parameters

    mapView

    The map view containing the annotation.

    annotationView

    The annotation view that was selected.

  • Tells the delegate that one of its annotation views was deselected.

    You can use this method to track changes in the selection state of annotation views.

    This method is only called for annotation views. To track changes in the selection state of all annotations, including those associated with static annotation images, implement -mapView:didDeselectAnnotation:, which is called immediately before this method is called.

    Declaration

    Objective-C

    - (void)mapView:(nonnull MGLMapView *)mapView
        didDeselectAnnotationView:(nonnull MGLAnnotationView *)annotationView;

    Swift

    optional func mapView(_ mapView: Any!, didDeselectAnnotationView annotationView: Any!)

    Parameters

    mapView

    The map view containing the annotation.

    annotationView

    The annotation view that was deselected.

  • Returns a Boolean value indicating whether the annotation is able to display extra information in a callout bubble.

    This method is called after an annotation is selected, before any callout is displayed for the annotation.

    If the return value is YES, a callout view is shown when the user taps on an annotation, selecting it. The default callout displays the annotation’s title and subtitle. You can add accessory views to either end of the callout by implementing the -mapView:leftCalloutAccessoryViewForAnnotation: and -mapView:rightCalloutAccessoryViewForAnnotation: methods. You can further customize the callout’s contents by implementing the -mapView:calloutViewForAnnotation: method.

    If the return value is NO, or if this method is absent from the delegate, or if the annotation lacks a title, the annotation will not show a callout even when selected.

    Declaration

    Objective-C

    - (BOOL)mapView:(nonnull MGLMapView *)mapView
        annotationCanShowCallout:(nonnull id<MGLAnnotation>)annotation;

    Swift

    optional func mapView(_ mapView: Any!, annotationCanShowCallout annotation: Any!) -> Any!

    Parameters

    mapView

    The map view that has selected the annotation.

    annotation

    The object representing the annotation.

    Return Value

    A Boolean value indicating whether the annotation should show a callout.

  • Returns a callout view to display for the given annotation.

    If this method is present in the delegate, it must return a new instance of a view dedicated to display the callout. The returned view will be configured by the map view.

    If this method is absent from the delegate, or if it returns nil, a standard, two-line, bubble-like callout view is displayed by default.

    Declaration

    Objective-C

    - (nullable UIView<MGLCalloutView> *)mapView:(nonnull MGLMapView *)mapView
                        calloutViewForAnnotation:
                            (nonnull id<MGLAnnotation>)annotation;

    Swift

    optional func mapView(_ mapView: Any!, calloutViewForAnnotation annotation: Any!) -> Any!

    Parameters

    mapView

    The map view that requested the callout view.

    annotation

    The object representing the annotation.

    Return Value

    A view conforming to the MGLCalloutView protocol, or nil to use the default callout view.

  • Returns the view to display on the left side of the standard callout bubble.

    The left callout view is typically used to convey information about the annotation or to link to custom information provided by your application.

    If the view you specify is a descendant of the UIControl class, you can use the map view’s delegate to receive notifications when your control is tapped, by implementing the -mapView:annotation:calloutAccessoryControlTapped: method. If the view you specify does not descend from UIControl, your view is responsible for handling any touch events within its bounds.

    If this method is absent from the delegate, or if it returns nil, the standard callout view has no accessory view on its left side. The return value of this method is ignored if -mapView:calloutViewForAnnotation: is present in the delegate.

    To display a view on the callout’s right side, implement the -mapView:rightCalloutAccessoryViewForAnnotation: method.

    Declaration

    Objective-C

    - (nullable UIView *)mapView:(nonnull MGLMapView *)mapView
        leftCalloutAccessoryViewForAnnotation:(nonnull id<MGLAnnotation>)annotation;

    Swift

    optional func mapView(_ mapView: Any!, leftCalloutAccessoryViewForAnnotation annotation: Any!) -> Any!

    Parameters

    mapView

    The map view presenting the annotation callout.

    annotation

    The object representing the annotation with the callout.

    Return Value

    The accessory view to display.

  • Returns the view to display on the right side of the standard callout bubble.

    The right callout view is typically used to convey information about the annotation or to link to custom information provided by your application.

    If the view you specify is a descendant of the UIControl class, you can use the map view’s delegate to receive notifications when your control is tapped, by implementing the -mapView:annotation:calloutAccessoryControlTapped: method. If the view you specify does not descend from UIControl, your view is responsible for handling any touch events within its bounds.

    If this method is absent from the delegate, or if it returns nil, the standard callout view has no accessory view on its right side. The return value of this method is ignored if -mapView:calloutViewForAnnotation: is present in the delegate.

    To display a view on the callout’s left side, implement the -mapView:leftCalloutAccessoryViewForAnnotation: method.

    Declaration

    Objective-C

    - (nullable UIView *)mapView:(nonnull MGLMapView *)mapView
        rightCalloutAccessoryViewForAnnotation:
            (nonnull id<MGLAnnotation>)annotation;

    Swift

    optional func mapView(_ mapView: Any!, rightCalloutAccessoryViewForAnnotation annotation: Any!) -> Any!

    Parameters

    mapView

    The map view presenting the annotation callout.

    annotation

    The object representing the annotation with the callout.

    Return Value

    The accessory view to display.

  • Tells the delegate that the user tapped one of the accessory controls in the annotation’s callout view.

    In a standard callout view, accessory views contain custom content and are positioned on either side of the annotation title text. If an accessory view you specify is a descendant of the UIControl class, the map view calls this method as a convenience whenever the user taps your view. You can use this method to respond to taps and perform any actions associated with that control. For example, if your control displays additional information about the annotation, you could use this method to present a modal panel with that information.

    If your custom accessory views are not descendants of the UIControl class, the map view does not call this method. If the annotation has a custom callout view via the -mapView:calloutViewForAnnotation: method, you can specify the custom accessory views using the MGLCalloutView protocol’s leftAccessoryView and rightAccessoryView properties.

    Declaration

    Objective-C

    - (void)mapView:(nonnull MGLMapView *)mapView
                           annotation:(nonnull id<MGLAnnotation>)annotation
        calloutAccessoryControlTapped:(nonnull UIControl *)control;

    Swift

    optional func mapView(_ mapView: Any!, annotation: Any!, calloutAccessoryControlTapped control: Any!)

    Parameters

    mapView

    The map view containing the specified annotation.

    annotation

    The annotation whose accessory view was tapped.

    control

    The control that was tapped.

  • Tells the delegate that the user tapped on an annotation’s callout view.

    This method is called when the user taps on the body of the callout view, as opposed to the callout’s left or right accessory view. If the annotation has a custom callout view via the -mapView:calloutViewForAnnotation: method, this method is only called whenever the callout view calls its delegate’s -[MGLCalloutViewDelegate calloutViewTapped:] method.

    If this method is present on the delegate, the standard callout view’s body momentarily highlights when the user taps it, whether or not this method does anything in response to the tap.

    Declaration

    Objective-C

    - (void)mapView:(nonnull MGLMapView *)mapView
        tapOnCalloutForAnnotation:(nonnull id<MGLAnnotation>)annotation;

    Swift

    optional func mapView(_ mapView: Any!, tapOnCalloutForAnnotation annotation: Any!)

    Parameters

    mapView

    The map view containing the specified annotation.

    annotation

    The annotation whose callout was tapped.