| Inherits from | |
| Conforms to | |
| Framework | /System/Library/Frameworks/MapKit.framework |
| Availability | Available in iOS 3.0 and later. |
| Declared in | MKMapView.h MKTypes.h |
An MKMapView object provides an embeddable map interface, similar to the one provided by the Maps application. You use this class as-is to display map information and to manipulate the map contents from your application. You can center the map on a given coordinate, specify the size of the area you want to display, and annotate the map with custom information.
Important: The MapKit framework uses Google services to provide map data. Use of this class and the associated interfaces binds you to the Google Maps/Google Earth API terms of service. You can find these terms of service at http://code.google.com/apis/maps/iphone/terms.html.
When you initialize a map view, you should specify the initial region for that map to display. You do this by setting the region property of the map. A region is defined by a center point and a horizontal and vertical distance, referred to as the span. The span defines how much of the map at the given point should be visible and is also how you set the zoom level. Specifying a large span results in the user seeing a wide geographical area and corresponds to a low zoom level. Specifying a small span results in the user seeing a more narrow geographical area and corresponds to a higher zoom level.
In addition to setting the span programmatically, the MKMapView class supports many standard interactions for changing the position and zoom level of the map. In particular, map views support flick and pinch gestures for scrolling around the map and zooming in and out. Support for these gestures is enabled by default but can also be disabled using the scrollEnabled and zoomEnabled properties.
In iOS 4.0 and later, you can also use projected map coordinates instead of regions to specify some values. When you project the curved surface of the globe onto a flat surface, you get a two-dimensional version of a map where longitude lines appear to be parallel. Locations and distances on this map are specified using the MKMapPoint, MKMapSize, and MKMapRect data types. You can use these data types to specify the map’s visible region and when specifying the location of overlays.
Although you should not subclass the MKMapView class itself, you can get information about the map view’s behavior by providing a delegate object. The map view calls the methods of your custom delegate to let it know about changes in the map status and to coordinate the display of custom annotations, which are described in more detail in “Annotating the Map.” The delegate object can be any object in your application as long as it conforms to the MKMapViewDelegate protocol. For more information about implementing the delegate object, see MKMapViewDelegate Protocol Reference.
The MKMapView class supports the ability to annotate the map with custom information. Because a map may have potentially large numbers of annotations, map views differentiate between the annotation objects used to manage the annotation data and the view objects for presenting that data on the map.
An annotation object is any object that conforms to the MKAnnotation protocol. Annotation objects are typically implemented using existing classes in your application’s data model. This allows you to manipulate the annotation data directly but still make it available to the map view. Each annotation object contains information about the annotation’s location on the map along with descriptive information that can be displayed in a callout.
The presentation of annotation objects on the screen is handled by an annotation view, which is an instance of the MKAnnotationView class. An annotation view is responsible for presenting the annotation data in a way that makes sense. For example, the Maps application uses a pin icon to denote specific points of interest on a map. (The MapKit framework offers the MKPinAnnotationView class for similar annotations in your own applications.) You could also create annotation views that cover larger portions of the map.
Because annotation views are needed only when they are onscreen, the MKMapView class provides a mechanism for queueing annotation views that are not in use. Annotation views with a reuse identifier can be detached and queued internally by the map view when they move off screen. This feature improves memory use by keeping only a small number of annotation views in memory at once and by recycling the views you do have. It also improves scrolling performance by alleviating the need to create new views while the map is scrolling.
When configuring your map interface, you should add all of your annotation objects right away. The map view uses the coordinate data in each annotation object to determine when the corresponding annotation view needs to appear on screen. When an annotation moves on screen, the map view asks its delegate to create a corresponding annotation view. If your application has different types of annotations, it can define different annotation view classes to represent each type.
In iOS 4.0 and later, you can use overlays to display content over a wide portion of the map. An overlay is any object that conforms to the MKOverlay protocol. An overlay object is a data object that contains the points needed to specify the shape and size of the overlay and its location on the map. Overlays can represent shapes such as circles, rectangles, multi-segment lines, and simple or complex polygons. You can also define your own custom overlays to represent other shapes.
The presentation of an overlay on screen is handled by an overlay view, which is an instance of the MKOverlayView class. The job of an overlay view is to draw the shape representing the overlay on top of the map content. For example, an overlay that represents a bus route might have an overlay view that draws the path of the route along with icons showing the stops along that route. The Map Kit framework defines overlay views for the standard types of overlay objects and you can define additional overlay views as needed.
When configuring your map interface, you can add overlay objects at any time. The map view uses the data in each overlay object to determine when the corresponding overlay view needs to appear on screen. When an overlay moves on screen, the map view asks its delegate to create a corresponding overlay view.
mapType property
zoomEnabled property
scrollEnabled property
delegate property
region property
– setRegion:animated:
centerCoordinate property
– setCenterCoordinate:animated:
visibleMapRect property
– setVisibleMapRect:animated:
– setVisibleMapRect:edgePadding:animated:
showsUserLocation property
userLocationVisible property
userLocation property
annotations property
– addAnnotation:
– addAnnotations:
– removeAnnotation:
– removeAnnotations:
– viewForAnnotation:
annotationVisibleRect property
– dequeueReusableAnnotationViewWithIdentifier:
overlays property
– addOverlay:
– addOverlays:
– removeOverlay:
– removeOverlays:
– insertOverlay:atIndex:
– exchangeOverlayAtIndex:withOverlayAtIndex:
– insertOverlay:aboveOverlay:
– insertOverlay:belowOverlay:
– viewForOverlay:
– convertCoordinate:toPointToView:
– convertPoint:toCoordinateFromView:
– convertRegion:toRectToView:
– convertRect:toRegionFromView:
For more about Objective-C properties, see “Properties” in The Objective-C Programming Language.
The complete list of annotations associated with the receiver. (read-only)
@property(nonatomic, readonly) NSArray *annotations
The objects in this array must adopt the MKAnnotation protocol. If no annotations are associated with the map view, the value of this property is nil.
MKMapView.hThe visible rectangle of the map view. (read-only)
@property(nonatomic, readonly) CGRect annotationVisibleRect
MKMapView.hThe map coordinate at the center of the map view.
@property(nonatomic) CLLocationCoordinate2D centerCoordinate
Changing the value in this property centers the map on the new coordinate without changing the current zoom level. It also updates the values in the region property to reflect the new center coordinate and the new span values needed to maintain the current zoom level.
Changing the value of this property updates the map view immediately. If you want to animate the change, use the setCenterCoordinate:animated: method instead.
MKMapView.hThe receiver’s delegate.
@property(nonatomic, assign) id<MKMapViewDelegate> delegate
A map view sends messages to its delegate regarding the loading of map data and changes in the portion of the map being displayed. The delegate also manages the annotation views used to highlight points of interest on the map.
The delegate should implement the methods of the MKMapViewDelegate protocol.
MKMapView.hThe type of data displayed by the map view.
@property(nonatomic) MKMapType mapType
Changing the value in this property may cause the receiver to begin loading new map content. For example, changing from MKMapTypeStandard to MKMapTypeSatellite might cause it to begin loading the satellite imagery needed for the map. If new data is needed, however, it is loaded asynchronously and appropriate messages are sent to the receiver’s delegate indicating the status of the operation.
MKMapView.hThe overlays currently associated with the map view. (read-only)
@property(nonatomic, readonly) NSArray *overlays
The objects in this array must adopt the MKOverlay protocol. If no overlays are associated with the map view, the value of this property is an empty array.
If the regions defined by two overlays intersect one another, the order of the objects in this array determines the z-order of the corresponding overlay views that are displayed in the map. Overlay objects at the beginning of the array are placed behind those that come later in the array. Thus, the view for an overlay at index 0 is displayed behind the view for the overlay at index 1.
MKMapView.hThe area currently displayed by the map view.
@property(nonatomic) MKCoordinateRegion region
The region encompasses both the latitude and longitude point on which the map is centered and the span of coordinates to display. The span values provide an implicit zoom value for the map. The larger the displayed area, the lower the amount of zoom. Similarly, the smaller the displayed area, the greater the amount of zoom.
Changing only the center coordinate of the region can still cause the span to change implicitly. This is due to the fact that the distances represented by a span change at different latitudes and longitudes and the map view may need to adjust the span to account for the new location. If you want to change the center coordinate without changing the zoom level, use the centerCoordinate instead.
Changing the value of this property updates the map view immediately. If you want to animate the change in region, use the setRegion:animated: method instead.
MKMapView.hA Boolean value that determines whether the user may scroll around the map.
@property(nonatomic, getter=isScrollEnabled) BOOL scrollEnabled
This property controls only user interactions with the map. If you set the value of this property to NO, you may still change the map location programmatically by changing the value in the region property.
The default value of this property is YES.
MKMapView.hThe annotations that are currently selected.
@property(nonatomic, copy) NSArray *selectedAnnotations
Assigning a new array to this property selects the first annotation in the array only.
MKMapView.hA Boolean value indicating whether the map may display the user location.
@property(nonatomic) BOOL showsUserLocation
This property does not indicate whether the user’s position is actually visible on the map, only whether the map view is allowed to display it. To determine whether the user’s position is visible, use the userLocationVisible property. The default value of this property is NO.
Setting this property to YES causes the map view to use the Core Location framework to find the current location. As long as this property is YES, the map view continues to track the user’s location and update it periodically.
MKMapView.hThe annotation object representing the user’s current location. (read-only)
@property(nonatomic, readonly) MKUserLocation *userLocation
MKMapView.hA Boolean value indicating whether the device’s current location is visible in the map view. (read-only)
@property(nonatomic, readonly, getter=isUserLocationVisible) BOOL userLocationVisible
This property uses the horizontal accuracy of the current location to determine whether the user’s location is visible. Thus, this property is YES if the specific coordinate is offscreen but the rectangle surrounding that coordinate (and defined by the horizontal accuracy value) is partially onscreen.
If the user’s location cannot be determined, this property contains the value NO.
MKMapView.hThe area currently displayed by the map view.
@property(nonatomic) MKMapRect visibleMapRect
This property represents the same basic information in the region property but specified as a map rectangle instead of a region.
Changing the value of this property updates the map view immediately. If you want to animate the change, use the setVisibleMapRect:animated: method instead.
MKMapView.hA Boolean value that determines whether the user may use pinch gestures to zoom in and out of the map.
@property(nonatomic, getter=isZoomEnabled) BOOL zoomEnabled
This property controls only user interactions with the map. If you set the value of this property to NO, you may still change the zoom level programmatically by changing the value in the region property.
The default value of this property is YES.
MKMapView.hAdds the specified annotation to the map view.
- (void)addAnnotation:(id < MKAnnotation >)annotation
The annotation object to add to the receiver. This object must conform to the MKAnnotation protocol. The map view retains the specified object.
MKMapView.hAdds an array of annotations to the map view.
- (void)addAnnotations:(NSArray *)annotations
An array of annotation objects. Each object in the array must conform to the MKAnnotation protocol. The map view retains the individual annotation objects.
MKMapView.hAdds a single overlay object to the map.
- (void)addOverlay:(id < MKOverlay >)overlay
The overlay object to add. This object must conform to the MKOverlay protocol.
The specified overlay is added to the end of the list of overlay objects. Adding an overlay causes the map view to begin monitoring the area represented by that overlay. As soon as the bounding rectangle of the overlay intersects the visible portion of the map, the map view adds a corresponding overlay view to the map. The overlay view is provided by the mapView:viewForOverlay: method of the map view’s delegate object.
To remove an overlay from a map, you must remove the overlay object using the removeOverlay: method.
MKMapView.hAdds an array of overlay objects to the map.
- (void)addOverlays:(NSArray *)overlays
An array of objects, each of which must conform to the MKOverlay protocol.
The specified objects are added to the end of the list of overlay objects. Adding an overlay causes the map view to begin monitoring the area represented by that overlay. As soon as the bounding rectangle of the overlay intersects the visible portion of the map, the map view adds a corresponding overlay view to the map. The overlay view is provided by the mapView:viewForOverlay: method of the map view’s delegate object.
To remove an overlay from a map, you must remove the overlay object using the removeOverlay: method.
MKMapView.hConverts a map coordinate to a point in the specified view.
- (CGPoint)convertCoordinate:(CLLocationCoordinate2D)coordinate toPointToView:(UIView *)view
The map coordinate for which you want to find the corresponding point.
The view in whose coordinate system you want to locate the specified map coordinate. If this parameter is nil, the returned point is specified in the window’s coordinate system. If view is not nil, it must belong to the same window as the map view.
The point (in the appropriate view or window coordinate system) corresponding to the specified latitude and longitude value.
MKMapView.hConverts a point in the specified view’s coordinate system to a map coordinate.
- (CLLocationCoordinate2D)convertPoint:(CGPoint)point toCoordinateFromView:(UIView *)view
The point you want to convert.
The view that serves as the reference coordinate system for the point parameter.
The map coordinate at the specified point.
MKMapView.hConverts a rectangle in the specified view’s coordinate system to a map region.
- (MKCoordinateRegion)convertRect:(CGRect)rect toRegionFromView:(UIView *)view
The rectangle you want to convert.
The view that serves as the reference coordinate system for the rect parameter.
The map region corresponding to the specified view rectangle.
MKMapView.hConverts a map region to a rectangle in the specified view.
- (CGRect)convertRegion:(MKCoordinateRegion)region toRectToView:(UIView *)view
The map region for which you want to find the corresponding view rectangle.
The view in whose coordinate system you want to locate the specified map region. If this parameter is nil, the returned rectangle is specified in the window’s coordinate system. If view is not nil, it must belong to the same window as the map view.
The rectangle corresponding to the specified map region.
MKMapView.hReturns a reusable annotation view located by its identifier.
- (MKAnnotationView *)dequeueReusableAnnotationViewWithIdentifier:(NSString *)identifier
A string identifying the annotation view to be reused. This is the same string that you specify when initializing the annotation view using the initWithAnnotation:reuseIdentifier: method.
An annotation view with the specified identifier, or nil if no such object exists in the reuse queue.
For performance reasons, you should generally reuse MKAnnotationView objects in your map views. As annotation views move offscreen, the map view moves them to an internally managed reuse queue. As new annotations move onscreen, and your code is prompted to provide a corresponding annotation view, you should always attempt to dequeue an existing view before creating a new one. Dequeueing saves time and memory during performance critical operations such as scrolling.
MKMapView.hDeselects the specified annotation and hides its callout view.
- (void)deselectAnnotation:(id < MKAnnotation >)annotation animated:(BOOL)animated
The annotation object to deselect.
If YES, the callout view is animated off screen.
MKMapView.hExchanges the position of two overlay objects.
- (void)exchangeOverlayAtIndex:(NSUInteger)index1 withOverlayAtIndex:(NSUInteger)index2
If either overlay object has an associated view, the position of that view is updated as well. Thus, exchanging views also affects the z-order of overlay views as they appear on the map view.
MKMapView.hInserts one overlay on top of another.
- (void)insertOverlay:(id < MKOverlay >)overlay aboveOverlay:(id < MKOverlay >)sibling
The overlay object to insert.
An existing object in the overlays array. This object must exist in the array and must not be nil.
This method adds the object in overlay to the map view and positions it relative to the specified sibling object in the overlays array. This position causes the view associated with overlay to be displayed on top of the view associated with sibling.
MKMapView.hInserts an overlay into the list of overlay objects associated with the map.
- (void)insertOverlay:(id < MKOverlay >)overlay atIndex:(NSUInteger)index
The overlay object to insert.
The index at which to insert the overlay object. If this value is greater than the number of objects in the overlays property, this method appends the object to the end of the array.
MKMapView.hPara
- (void)insertOverlay:(id < MKOverlay >)overlay belowOverlay:(id < MKOverlay >)sibling
The overlay object to insert.
An existing object in the overlays array. This object must exist in the array and must not be nil.
This method adds the object in overlay to the map view and positions it relative to the specified sibling object in the overlays array. This position causes the view associated with overlay to be displayed behind the view associated with sibling.
MKMapView.hAdjusts the aspect ratio of the specified map rectangle to ensure that it fits in the map view’s frame.
- (MKMapRect)mapRectThatFits:(MKMapRect)mapRect
The initial map rectangle whose width and height you want to adjust.
A map rectangle that is still centered on the same point of the map but whose width and height are adjusted to fit in the map view’s frame.
You can use this method to normalize map rectangle values before displaying the corresponding area. This method returns a new map rectangle that both contains the specified rectangle and fits neatly inside the map view’s frame.
MKMapView.hAdjusts the aspect ratio of the specified map rectangle, incorporating the specified inset values.
- (MKMapRect)mapRectThatFits:(MKMapRect)mapRect edgePadding:(UIEdgeInsets)insets
The initial map rectangle whose width and height you want to adjust.
The distance (measured in screen points) by which to inset the returned rectangle from the actual boundaries of the map view’s frame.
A map rectangle that is still centered on the same point of the map but whose width and height are adjusted to fit in the map view’s frame minus the inset values.
MKMapView.hAdjusts the aspect ratio of the specified region to ensure that it fits in the map view’s frame.
- (MKCoordinateRegion)regionThatFits:(MKCoordinateRegion)region
The initial region whose span you want to adjust.
A region that is still centered on the same point of the map but whose span values are adjusted to fit in the map view’s frame.
You can use this method to normalize the region values before displaying them in the map. This method returns a new region that both contains the specified region and fits neatly inside the map view’s frame.
MKMapView.hRemoves the specified annotation object from the map view.
- (void)removeAnnotation:(id < MKAnnotation >)annotation
The annotation object to remove. This object must conform to the MKAnnotation protocol.
If the annotation is currently associated with an annotation view, and that view has a reuse identifier, this method removes the annotation view and queues it internally for later reuse. You can retrieve queued annotation views (and associate them with new annotations) using the dequeueReusableAnnotationViewWithIdentifier: method.
Removing an annotation object disassociates it from the map view entirely, preventing it from being displayed on the map. Thus, you would typically call this method only when you want to hide or delete a given annotation.
MKMapView.hRemoves the specified annotation objects from the map view.
- (void)removeAnnotations:(NSArray *)annotations
The array of annotations to remove. Objects in the array must conform to the MKAnnotation protocol.
If any annotation object in the array has an associated annotation view, and if that view has a reuse identifier, this method removes the annotation view and queues it internally for later reuse. You can retrieve queued annotation views (and associate them with new annotations) using the dequeueReusableAnnotationViewWithIdentifier: method.
Removing annotation objects disassociates them from the map view entirely, preventing them from being displayed on the map. Thus, you would typically call this method only when you want to hide or delete the specified annotations.
MKMapView.hRemoves a single overlays from the map.
- (void)removeOverlay:(id < MKOverlay >)overlay
The overlay object to remove.
Removing an overlay object removes the corresponding overlay view, if one is currently displayed. If the specified object is not currently associated with the map view, this method does nothing.
MKMapView.hRemoves one or more overlays from the map.
- (void)removeOverlays:(NSArray *)overlays
An array of objects, each of which conforms to the MKOverlay protocol.
Removing an overlay object removes the corresponding overlay view, if one is currently displayed. If one or more of the overlay objects are not currently associated with the map view, this method removes the objects that are associated with the map and ignores the rest.
MKMapView.hSelects the specified annotation and displays a callout view for it.
- (void)selectAnnotation:(id < MKAnnotation >)annotation animated:(BOOL)animated
The annotation object to select.
If YES, the callout view is animated into position.
If the specified annotation is not onscreen, and therefore does not have an associated annotation view, this method has no effect.
MKMapView.hChanges the center coordinate of the map and optionally animates the change.
- (void)setCenterCoordinate:(CLLocationCoordinate2D)coordinate animated:(BOOL)animated
The new center coordinate for the map.
Specify YES if you want the map view to scroll to the new location or NO if you want the map to display the new location immediately.
Changing the center coordinate centers the map on the new coordinate without changing the current zoom level. It also updates the values in the region property to reflect the new center coordinate and the new span values needed to maintain the current zoom level.
MKMapView.hChanges the currently visible region and optionally animates the change.
- (void)setRegion:(MKCoordinateRegion)region animated:(BOOL)animated
The new region to display in the map view.
Specify YES if you want the map view to animate the transition to the new region or NO if you want the map to center on the specified region immediately.
Changing just the center coordinate of the region can still cause the span values to change implicitly. This is due to the fact that the distances represented by a span change at different latitudes and longitudes and the map view may need to adjust the span to account for the new location. If you want to change the center coordinate without changing the zoom level, use the setCenterCoordinate:animated: instead.
MKMapView.hChanges the currently visible portion of the map and optionally animates the change.
- (void)setVisibleMapRect:(MKMapRect)mapRect animated:(BOOL)animate
The map rectangle to make visible in the map view.
Specify YES if you want the map view to animate the transition to the new map rectangle or NO if you want the map to center on the specified rectangle immediately.
MKMapView.hChanges the currently visible portion of the map, allowing you to specify additional space around the edges.
- (void)setVisibleMapRect:(MKMapRect)mapRect edgePadding:(UIEdgeInsets)insets animated:(BOOL)animate
The map rectangle to make visible in the map view.
The amount of additional space (measured in screen points) to make visible around the specified rectangle.
Specify YES if you want the map view to animate the transition to the new map rectangle or NO if you want the map to center on the specified rectangle immediately.
MKMapView.hReturns the annotation view associated with the specified annotation object, if any.
- (MKAnnotationView *)viewForAnnotation:(id < MKAnnotation >)annotation
The annotation object whose view you want.
The annotation view or nil if the view has not yet been created. This method may also return nil if the annotation is not in the visible map region and therefore does not have an associated annotation view.
MKMapView.hReturns the view (if any) associated with the overlay object.
- (MKOverlayView *)viewForOverlay:(id < MKOverlay >)overlay
The overlay object whose view you want.
The view associated with the overlay object or nil if the overlay is not on screen.
MKMapView.hThe type of map to display.
enum {
MKMapTypeStandard,
MKMapTypeSatellite,
MKMapTypeHybrid
};
typedef NSUInteger MKMapType;
MKMapTypeStandardDisplays a street map that shows the position of all roads and some road names.
Available in iOS 3.0 and later.
Declared in MKTypes.h.
MKMapTypeSatelliteDisplays satellite imagery of the area.
Available in iOS 3.0 and later.
Declared in MKTypes.h.
MKMapTypeHybridDisplays a satellite image of the area with road and road name information layered on top.
Available in iOS 3.0 and later.
Declared in MKTypes.h.
Last updated: 2010-05-11