Customize the MKAnnotationView callout

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南方客
南方客 2020-11-28 18:19

I want to create a custom MKAnnotationView callout as shown in this image. I have tested several solutions but they only allow customization of the left/right images and tit

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  • 2020-11-28 18:57

    I understand you want a pin with a custom callout.

    We can't create a custom callout, but we can create an annotation with a completely customized view. So the trick is to add a second annotation when the first is selected, and make the 2nd annotation view look like a callout bubble.

    This is the solution posted by users djibouti33 and jacob-jennings in the answer: MKAnnotationView - Lock custom annotation view to pin on location updates, which in turn is based in a blog post from Asynchrony Solutions. For explanation purposes, here is some UML from a forked project: Annotation with custom XIB

    This is a big hack, but also the cleanest way I've seen to implement custom annotations.

    Start with a NSObject "Content" class which has a coordinate, the class of the callout view to use (in the UML is AnnotationView, but you can create more and set them here), and a dictionary of random values with the title, photo url, etc. Use this class to initialize a MKAnnotation "Annotation" object.

    #import <MapKit/MapKit.h>
    @interface Content : NSObject
    @property (nonatomic,assign) CLLocationCoordinate2D coordinate;
    // ...
    
    @interface Annotation : NSObject <MKAnnotation, AnnotationProtocol>
    -(id) initWithContent:(Content*)content;
    // ...
    

    The Annotation implements AnnotationProtocol to announce it wants to handle the creation of its own MKAnnotationView. That is, your MKMapViewDelegate should have code like this:

    - (MKAnnotationView *)mapView:(MKMapView *)aMapView viewForAnnotation:(id<MKAnnotation>)annotation 
    {
        // if this is a custom annotation, delegate the implementation of the view
        if ([annotation conformsToProtocol:@protocol(AnnotationProtocol)]) {
            return [((NSObject<AnnotationProtocol>*)annotation) annotationViewInMap:mapView];
        } else {
            // else, return a standard annotation view
            // ...
        }
    } 
    

    The view returned will be of type AnnotationView, which implements AnnotationViewProtocol to announce that it wants to handle selection/deselection. Therefore, in your map view controller, the methods mapView:didSelectAnnotationView: and mapView:didDeselectAnnotationView: should delegate in a similar way to what we saw before.

    When the annotation is selected, a second annotation (CalloutAnnotation) is added, which follows the same behaviour, but this time the view returned (CalloutView) is initialized from a XIB, and contains Core Graphics code (in BaseCalloutView) to animate and replicate a callout.

    The initializer of the CalloutView class:

    - (id)initWithAnnotation:(CalloutAnnotation*)annotation
    {
        NSString *identifier = NSStringFromClass([self class]);
        self = [super initWithAnnotation:annotation reuseIdentifier:identifier];
        if (self!=nil){
            [[NSBundle mainBundle] loadNibNamed:identifier owner:self options:nil];
            // prevent the tap and double tap from reaching views underneath
            UITapGestureRecognizer *tapGestureRecognizer = ...
        }
        return self;
    }
    

    To be able to push another view controller from the callout view I used notifications.

    The SO answer I linked at the top contains two complete projects implementing this code (class names may differ). I have another project using the UML above at https://github.com/j4n0/callout.

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  • 2020-11-28 19:12

    I added custom UIButton in MKAnnotationView. And on click of that button I have shown popOver with rootViewController with the view similar as you have shown above.

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  • 2020-11-28 19:14

    I know this question is from 2011 but for people who still find it in a search: In iOS 9 you have MKAnnotationView.detailCalloutAccessoryView which entirely replaces the standard callout.

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