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 annotation marker symbology and to manage interactions with those markers.

  • Tells the delegate that the region displayed by the map view is about to change.

    This method is called whenever the currently displayed map region will start changing.

    Declaration

    Objective-C

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

    Parameters

    mapView

    The map view whose visible region will change.

    animated

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

  • Tells the delegate that the region displayed by the map view is changing.

    This method is called whenever the currently displayed map region changes. During movement, this method may be called many times to report updates to the map position. Therefore, your implementation of this method should be as lightweight as possible to avoid affecting performance.

    Declaration

    Objective-C

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

    Parameters

    mapView

    The map view whose visible region is changing.

  • Tells the delegate that the region displayed by the map view just changed.

    This method is called whenever the currently displayed map region has finished changing.

    Declaration

    Objective-C

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

    Parameters

    mapView

    The map view whose visible region 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;

    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;

    Parameters

    mapView

    The map view that has finished loading.

  • 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;

    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;

    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;

    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;

    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;

    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 image object to use for the marker for the specified point annotation object.

    Declaration

    Objective-C

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

    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 image object to display for the specified annotation or nil if you want to display the default marker image.

  • Returns the alpha value to use when rendering a shape annotation. Defaults to 1.0.

    Declaration

    Objective-C

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

    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 stroke color to use when rendering a shape annotation. Defaults to the map view’s tint color.

    Declaration

    Objective-C

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

    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 fill color to use when rendering a polygon annotation. Defaults to the map view’s tint color.

    Declaration

    Objective-C

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

    Parameters

    mapView

    The map view rendering the polygon annotation.

    annotation

    The annotation being rendered.

    Return Value

    A color to use for the polygon interior.

  • Returns the line width to use when rendering a polyline annotation. Defaults to 3.0.

    Declaration

    Objective-C

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

    Parameters

    mapView

    The map view rendering the polygon annotation.

    annotation

    The annotation being rendered.

    Return Value

    A line width for the polyline.

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

    If the value returned is YES, a standard callout bubble is shown when the user taps a selected annotation. The callout uses the title and subtitle text from the associated annotation object. If there is no title text, though, the annotation will not show a callout. The callout also displays any custom callout views returned by the delegate for the left and right callout accessory views.

    If the value returned is NO, the value of the title and subtitle strings are ignored.

    Declaration

    Objective-C

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

    Parameters

    mapView

    The map view that requested the annotation callout ability.

    annotation

    The object representing the annotation.

    Return Value

    A Boolean indicating whether the annotation should show a callout.

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

    If this method is present in the delegate, it must return a new instance of a view dedicated to display the callout bubble. It will be configured by the map view. If this method is not present, 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;

    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 default value is treated as if nil. The left callout view is typically used to display information about the annotation or to link to custom information provided by your application.

    If the view you specify is also a descendant of the UIControl class, you can use the map view’s delegate to receive notifications when your control is tapped. If it does not descend from UIControl, your view is responsible for handling any touch events within its bounds.

    Declaration

    Objective-C

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

    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 default value is treated is if nil. The right callout view is typically used to link to more detailed information about the annotation. A common view to specify for this property is UIButton object whose type is set to UIButtonTypeDetailDisclosure.

    If the view you specify is also a descendant of the UIControl class, you can use the map view’s delegate to receive notifications when your control is tapped. If it does not descend from UIControl, your view is responsible for handling any touch events within its bounds.

    Declaration

    Objective-C

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

    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 annotation’s accessory buttons.

    Accessory views contain custom content and are positioned on either side of the annotation title text. If a 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 displayed 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.

    Declaration

    Objective-C

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

    Parameters

    mapView

    The map view containing the specified annotation.

    annotation

    The annotation whose button was tapped.

    control

    The control that was tapped.

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

    Declaration

    Objective-C

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

    Parameters

    mapView

    The map view containing the specified annotation.

    annotation

    The annotation whose callout was tapped.

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

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

    Declaration

    Objective-C

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

    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.

    Declaration

    Objective-C

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

    Parameters

    mapView

    The map view containing the annotation.

    annotation

    The annotation that was deselected.