# 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.

### Responding to Map Position Changes

- `-mapView:shouldChangeFromCamera:toCamera:`

  Asks the delegate whether the map view should be allowed to change from the existing camera to the new camera in response to a user gesture.

  This method is called as soon as the user gesture is recognized. It is not called in response to a programmatic camera change, such as by setting the `centerCoordinate` property or calling `-flyToCamera:completionHandler:`.

  This method is called many times during gesturing, so you should avoid performing complex or performance-intensive tasks in your implementation.

  #### Related examples

  See the Restrict map panning to an area example to learn how to use this method and `MGLMapCamera` objects to restrict a users ability to pan your map.

  #### Declaration

  Objective-C

      - (BOOL)mapView:(nonnull MGLMapView *)mapView
          shouldChangeFromCamera:(nonnull MGLMapCamera *)oldCamera
                        toCamera:(nonnull MGLMapCamera *)newCamera;

  Swift

      optional func mapView(_ mapView: MGLMapView, shouldChangeFrom oldCamera: MGLMapCamera, to newCamera: MGLMapCamera) -> Bool

  #### Parameters

  `mapView` | The map view that the user is manipulating.
  `oldCamera` | The camera representing the viewpoint at the moment the gesture is recognized. If this method returns `NO`, the map view’s camera continues to be this camera.
  `newCamera` | The expected camera after the gesture completes. If this method returns `YES`, this camera becomes the map view’s camera.

  #### Return Value

  A Boolean value indicating whether the map view should stay at `oldCamera` or change to `newCamera`.

  View Source on GitHub
- `-mapView:regionWillChangeAnimated:`

  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: MGLMapView, regionWillChangeAnimated animated: Bool)

  #### Parameters

  `mapView` | The map view whose viewpoint will change.
  `animated` | Whether the change will cause an animated effect on the map.

  View Source on GitHub
- `-mapViewRegionIsChanging:`

  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:]`. This method can be called before `-mapViewDidFinishLoadingMap:` is called.

  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.

  #### Related examples

  See the Cluster point data example to learn how to trigger an action whenever the map region changes.

  #### Declaration

  Objective-C

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

  Swift

      optional func mapViewRegionIsChanging(_ mapView: MGLMapView)

  #### Parameters

  `mapView` | The map view whose viewpoint is changing.

  View Source on GitHub
- `-mapView:regionDidChangeAnimated:`

  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. Therefore, this method can be called before `-mapViewDidFinishLoadingMap:` is called.

  #### Declaration

  Objective-C

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

  Swift

      optional func mapView(_ mapView: MGLMapView, regionDidChangeAnimated animated: Bool)

  #### Parameters

  `mapView` | The map view whose viewpoint has changed.
  `animated` | Whether the change caused an animated effect on the map.

  View Source on GitHub

### Loading the Map

- `-mapViewWillStartLoadingMap:`

  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: MGLMapView)

  #### Parameters

  `mapView` | The map view that is starting to load.

  View Source on GitHub
- `-mapViewDidFinishLoadingMap:`

  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: MGLMapView)

  #### Parameters

  `mapView` | The map view that has finished loading.

  View Source on GitHub
- `-mapViewDidFailLoadingMap:withError:`

  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: MGLMapView, withError error: Error)

  #### Parameters

  `mapView` | The map view that is unable to load the data.
  `error` | The reason the data could not be loaded.

  View Source on GitHub
- `-mapViewWillStartRenderingFrame:`

  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: MGLMapView)

  #### Parameters

  `mapView` | The map view that is about to redraw.

  View Source on GitHub
- `-mapViewDidFinishRenderingFrame:fullyRendered:`

  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: MGLMapView, fullyRendered: Bool)

  #### Parameters

  `mapView` | The map view that has just redrawn.

  View Source on GitHub
- `-mapViewDidBecomeIdle:`

  Tells the delegate that the map view is entering an idle state, and no more drawing will be necessary until new data is loaded or there is some interaction with the map.

  - No camera transitions are in progress
  - All currently requested tiles have loaded

  - All fade/transition animations have completed

  #### Declaration

  Objective-C

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

  Swift

      optional func mapViewDidBecomeIdle(_ mapView: MGLMapView)

  #### Parameters

  `mapView` | The map view that has just entered the idle state.

  View Source on GitHub
- `-mapView:didFinishLoadingStyle:`

  Tells the delegate that the map has just finished loading a style.

  This method is called during the initialization of the map view and after any subsequent loading of a new style. This method is called between the `-mapViewWillStartRenderingMap:` and `-mapViewDidFinishRenderingMap:` delegate methods. Changes to sources or layers of the current style do not cause this method to be called.

  This method is the earliest opportunity to modify the layout or appearance of the current style before the map view is displayed to the user.

  #### Related examples

  See the Dynamically style interactive points and Add multiple shapes from a single shape source examples to learn how to ensure a map’s style has loaded before modifying it at runtime.

  #### Declaration

  Objective-C

      - (void)mapView:(nonnull MGLMapView *)mapView
          didFinishLoadingStyle:(nonnull MGLStyle *)style;

  Swift

      optional func mapView(_ mapView: MGLMapView, didFinishLoading style: MGLStyle)

  #### Parameters

  `mapView` | The map view that has just loaded a style.
  `style` | The style that was loaded.

  View Source on GitHub

### Tracking User Location

- `-mapViewWillStartLocatingUser:`

  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: MGLMapView)

  #### Parameters

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

  View Source on GitHub
- `-mapViewDidStopLocatingUser:`

  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: MGLMapView)

  #### Parameters

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

  View Source on GitHub
- `-mapView:didUpdateUserLocation:`

  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: MGLMapView, didUpdate userLocation: MGLUserLocation?)

  #### 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`.

  View Source on GitHub
- `-mapView:didFailToLocateUserWithError:`

  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: MGLMapView, didFailToLocateUserWithError error: Error)

  #### Parameters

  `mapView` | The map view that is tracking the user’s location.
  `error` | An error object containing the reason why location tracking failed.

  View Source on GitHub
- `-mapView:didChangeUserTrackingMode:animated:`

  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: MGLMapView, didChange mode: MGLUserTrackingMode, animated: Bool)

  #### 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.

  View Source on GitHub
- `-mapViewUserLocationAnchorPoint:`

  Returns a screen coordinate at which to position the user location annotation. This coordinate is relative to the map view’s origin after applying the map view’s content insets.

  When unimplemented, the user location annotation is aligned within the center of the map view with respect to the content insets.

  This method will override any values set by `MGLMapView.userLocationVerticalAlignment` or `-[MGLMapView setUserLocationVerticalAlignment:animated:]`.

  #### Declaration

  Objective-C

      - (CGPoint)mapViewUserLocationAnchorPoint:(nonnull MGLMapView *)mapView;

  Swift

      optional func mapViewUserLocationAnchorPoint(_ mapView: MGLMapView) -> CGPoint

  #### Parameters

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

  View Source on GitHub

### Managing the Appearance of Annotations

- `-mapView:imageForAnnotation:`

  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.

  #### Related examples

  See the Annotation models, Add annotation views and images, and Mark a place on the map with an image examples to learn to specify which image should be used for `MGLAnnotation` objects that have been added to your map.

  #### Declaration

  Objective-C

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

  Swift

      optional func mapView(_ mapView: MGLMapView, imageFor annotation: MGLAnnotation) -> MGLAnnotationImage?

  #### 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.

  View Source on GitHub
- `-mapView:alphaForShapeAnnotation:`

  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.

  This method sets the opacity of an entire shape, inclusive of its stroke and fill. To independently set the values for stroke or fill, specify an alpha component in the color returned by `-mapView:strokeColorForShapeAnnotation:` or `-mapView:fillColorForPolygonAnnotation:`.

  #### Declaration

  Objective-C

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

  Swift

      optional func mapView(_ mapView: MGLMapView, alphaForShapeAnnotation annotation: MGLShape) -> CGFloat

  #### Parameters

  `mapView` | The map view rendering the shape annotation.
  `annotation` | The annotation being rendered.

  #### Return Value

  An alpha value between `0` and `1.0`.

  View Source on GitHub
- `-mapView:strokeColorForShapeAnnotation:`

  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.

  Opacity may be set by specifying an alpha component. The default alpha value is `1.0` and results in a completely opaque stroke.

  #### Related examples

  See the Annotation models example to learn how to modify the outline color of an `MGLShape` object that has been added to your map as an annotation.

  #### Declaration

  Objective-C

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

  Swift

      optional func mapView(_ mapView: MGLMapView, strokeColorForShapeAnnotation annotation: MGLShape) -> UIColor

  #### Parameters

  `mapView` | The map view rendering the shape annotation.
  `annotation` | The annotation being rendered.

  #### Return Value

  A color to use for the shape outline.

  View Source on GitHub
- `-mapView:fillColorForPolygonAnnotation:`

  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.

  Opacity may be set by specifying an alpha component. The default alpha value is `1.0` and results in a completely opaque shape.

  #### Related examples

  See the Add a polygon annotation example to learn how to modify the color of a an `MGLPolygon` at runtime.

  #### Declaration

  Objective-C

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

  Swift

      optional func mapView(_ mapView: MGLMapView, fillColorForPolygonAnnotation annotation: MGLPolygon) -> UIColor

  #### Parameters

  `mapView` | The map view rendering the polygon annotation.
  `annotation` | The annotation being rendered.

  #### Return Value

  The polygon’s interior fill color.

  View Source on GitHub
- `-mapView:lineWidthForPolylineAnnotation:`

  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.

  #### Related examples

  See the Add a line annotation from GeoJSON example to learn how to modify the line width of an `MGLPolylineFeature` on your map.

  #### Declaration

  Objective-C

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

  Swift

      optional func mapView(_ mapView: MGLMapView, lineWidthForPolylineAnnotation annotation: MGLPolyline) -> CGFloat

  #### 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.

  View Source on GitHub

### Managing Annotation Views

- `-mapView:viewForAnnotation:`

  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).

  #### Related examples

  See the Add annotation views and images example to learn how to specify what `MGLViewAnnotation` to use for a given `MGLPointAnnotation` object on your map.

  #### Declaration

  Objective-C

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

  Swift

      optional func mapView(_ mapView: MGLMapView, viewFor annotation: MGLAnnotation) -> MGLAnnotationView?

  #### 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.

  View Source on GitHub
- `-mapView:didAddAnnotationViews:`

  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: MGLMapView, didAdd annotationViews: [MGLAnnotationView])

  #### Parameters

  `mapView` | The map view to which the annotation views were added.
  `annotationViews` | An array of `MGLAnnotationView` objects representing the views that were added.

  View Source on GitHub

### Selecting Annotations

- `-mapView:shapeAnnotationIsEnabled:`

  Returns a Boolean value indicating whether the shape annotation can be selected.

  If the return value is `YES`, the user can select the annotation by tapping on it. If the delegate does not implement this method, the default value is `YES`.

  #### Declaration

  Objective-C

      - (BOOL)mapView:(nonnull MGLMapView *)mapView
          shapeAnnotationIsEnabled:(nonnull MGLShape *)annotation;

  Swift

      optional func mapView(_ mapView: MGLMapView, shapeAnnotationIsEnabled annotation: MGLShape) -> Bool

  #### Parameters

  `mapView` | The map view that has selected the annotation.
  `annotation` | The object representing the shape annotation.

  #### Return Value

  A Boolean value indicating whether the annotation can be selected.

  View Source on GitHub
- `-mapView:didSelectAnnotation:`

  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.

  #### Related examples

  See the Dynamically style interactive points example to learn how to remove an annotation view if it has already been selected.

  #### Declaration

  Objective-C

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

  Swift

      optional func mapView(_ mapView: MGLMapView, didSelect annotation: MGLAnnotation)

  #### Parameters

  `mapView` | The map view containing the annotation.
  `annotation` | The annotation that was selected.

  View Source on GitHub
- `-mapView:didDeselectAnnotation:`

  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: MGLMapView, didDeselect annotation: MGLAnnotation)

  #### Parameters

  `mapView` | The map view containing the annotation.
  `annotation` | The annotation that was deselected.

  View Source on GitHub
- `-mapView:didSelectAnnotationView:`

  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: MGLMapView, didSelect annotationView: MGLAnnotationView)

  #### Parameters

  `mapView` | The map view containing the annotation.
  `annotationView` | The annotation view that was selected.

  View Source on GitHub
- `-mapView:didDeselectAnnotationView:`

  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: MGLMapView, didDeselect annotationView: MGLAnnotationView)

  #### Parameters

  `mapView` | The map view containing the annotation.
  `annotationView` | The annotation view that was deselected.

  View Source on GitHub

### Managing Callout Views

- `-mapView:annotationCanShowCallout:`

  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.

  #### Related examples

  See the Add annotation views and images, Display custom views as callouts, and Default callout usage examples to learn how to show callouts for `MGLAnnotation` objects.

  #### Declaration

  Objective-C

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

  Swift

      optional func mapView(_ mapView: MGLMapView, annotationCanShowCallout annotation: MGLAnnotation) -> Bool

  #### 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.

  View Source on GitHub
- `-mapView:calloutViewForAnnotation:`

  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.

  #### Related examples

  See the Display custom views as callouts example to learn how to customize an `MGLAnnotation` object’s `MGLCalloutView`.

  #### Declaration

  Objective-C

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

  Swift

      optional func mapView(_ mapView: MGLMapView, calloutViewFor annotation: MGLAnnotation) -> MGLCalloutView?

  #### 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.

  View Source on GitHub
- `-mapView:leftCalloutAccessoryViewForAnnotation:`

  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.

  #### Related examples

  See the Default callout usage example to learn how to modify the view that is displayed on the left side of the standard callout bubble.

  #### Declaration

  Objective-C

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

  Swift

      optional func mapView(_ mapView: MGLMapView, leftCalloutAccessoryViewFor annotation: MGLAnnotation) -> UIView?

  #### 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.

  View Source on GitHub
- `-mapView:rightCalloutAccessoryViewForAnnotation:`

  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.

  #### Related examples

  See the Default callout usage example to learn how to modify the view that is displayed on the right side of the standard callout bubble.

  #### Declaration

  Objective-C

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

  Swift

      optional func mapView(_ mapView: MGLMapView, rightCalloutAccessoryViewFor annotation: MGLAnnotation) -> UIView?

  #### 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.

  View Source on GitHub
- `-mapView:annotation:calloutAccessoryControlTapped:`

  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.

  #### Related examples

  See the Default callout usage example to learn how to trigger an action when the standard callout bubble’s accessory control is tapped.

  #### Declaration

  Objective-C

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

  Swift

      optional func mapView(_ mapView: MGLMapView, annotation: MGLAnnotation, calloutAccessoryControlTapped control: UIControl)

  #### Parameters

  `mapView` | The map view containing the specified annotation.
  `annotation` | The annotation whose accessory view was tapped.
  `control` | The control that was tapped.

  View Source on GitHub
- `-mapView:tapOnCalloutForAnnotation:`

  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.

  #### Related examples

  See the Display custom views as callouts example to learn how to trigger an action when an `MGLAnnotation`s `MGLCalloutView` is tapped.

  #### Declaration

  Objective-C

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

  Swift

      optional func mapView(_ mapView: MGLMapView, tapOnCalloutFor annotation: MGLAnnotation)

  #### Parameters

  `mapView` | The map view containing the specified annotation.
  `annotation` | The annotation whose callout was tapped.

  View Source on GitHub