MapView with multiple annotations with callouts, how to pass title to next view

问题

I have a mapView where users press to drop a pin. There may be multiple pins at one time, and each annotation view has a callout that pushes a new view to the stack when it is pressed. What I want to do is pass the title of the annotation view to the label in the second view.

Here is the code where I drop the pin:

-(void)press:(UILongPressGestureRecognizer *)recognizer
{
    CGPoint touchPoint = [recognizer locationInView:worldView];
    CLLocationCoordinate2D touchMapCoordinate = [worldView convertPoint:touchPoint toCoordinateFromView:worldView];

    geocoder = [[CLGeocoder alloc]init];
    CLLocation *location = [[CLLocation alloc]initWithCoordinate:touchMapCoordinate
                                                    altitude:CLLocationDistanceMax
                                          horizontalAccuracy:kCLLocationAccuracyBest
                                            verticalAccuracy:kCLLocationAccuracyBest
                                                   timestamp:[NSDate date]];
    [geocoder reverseGeocodeLocation:location
               completionHandler:^(NSArray *placemarks, NSError *error) {
                   NSLog(@"reverseGeocoder:completionHandler: called");
                   if (error) {
                       NSLog(@"Geocoder failed with error: %@", error);
                   } else {
                       CLPlacemark *place = [placemarks objectAtIndex:0];
                       address = [NSString stringWithFormat:@"%@ %@, %@ %@", [place subThoroughfare], [place thoroughfare], [place locality], [place administrativeArea]];

                       if (UIGestureRecognizerStateBegan == [recognizer state]) {
                           addressPin = [[MapPoint alloc]initWithCoordinate:touchMapCoordinate
                                                                        title:address];
                           [worldView addAnnotation:addressPin];
                       }
                   }
               }];
}

And here is the code where I call the second view:

-(void)mapView:(MKMapView *)mapView annotationView:(MKAnnotationView *)view calloutAccessoryControlTapped:(UIControl *)control
{
   PinViewController *pinViewController = [[PinViewController alloc]init];
    [self passValues];
    [[self navigationController]pushViewController:pinViewController animated:YES];
}

回答1:

You can override MKAnnotation (for example MyLocation)and declare in MyLocation.h file

#import <Foundation/Foundation.h>
#import <MapKit/MapKit.h>

@interface MyLocation : NSObject <MKAnnotation> {
    NSNumber *identyfier;
    NSString *_name;
    NSString *_address;
    CLLocationCoordinate2D _coordinate;
}

@property (copy) NSString *name;
@property (copy) NSString *address;
@property (copy) NSNumber *identyfier;
@property (nonatomic, readonly) CLLocationCoordinate2D coordinate;

- (id)initWithName:(NSString*)name address:(NSString*)address 
    coordinate:(CLLocationCoordinate2D)coordinate identyfier:(NSNumber *) identyfier;

@end

in MyLocation.m file:

#import "MyLocation.h"

@implementation MyLocation

@synthesize name = _name;
@synthesize address = _address;
@synthesize coordinate = _coordinate;
@synthesize identyfier = _identyfier;

- (id)initWithName:(NSString*)name address:(NSString*)address 
    coordinate:(CLLocationCoordinate2D)coordinate identyfier:(NSNumber *)identyfier {
    if ((self = [super init])) {
        _name = [name copy];
        _address = [address copy];
        _coordinate = coordinate;
        _identyfier = identyfier;
    }
    return self;
}

In your map view when you declare annotation use this methos:

MyLocation *pin = [[MyLocation alloc] initWithName:place.name address:place.address coordinate:coordinate2D identyfier:some_id];

So for example in your map delegate:

- (MKAnnotationView *) mapView:(MKMapView *)mapView viewForAnnotation:(id<MKAnnotation>)annotation {

you can use:

((MyLocation *)annotation).identyfier

to check selected annotation (of course you can use different variables in MyLocation class)

回答2:

Usually when i need to pass variables i just create a global variable that then can be read by both view.

There is the

extern (NSString *)some_variable_name, which you put in the .h file and in the .m file you globally put (NSString *)some_variable_name ;

Which the can be read by all views

Or the + sign in front of you variable, which then can be read by all views that includes the view (setting the global at the top in the .m file, and in the .h file by the comman

something = [someview that_variable] ;

来源：https://stackoverflow.com/questions/13058659/mapview-with-multiple-annotations-with-callouts-how-to-pass-title-to-next-view

标签

objective-c

annotations

callouts