CODEWITHSUNDEEP
iosuiviewcontrollermkmapviewmkannotationappdelegate
Guilherme Miranda
Guilherme Miranda

Reputation: 1082

Add Annotation to map from another View

I'm trying to call plotParkingLots from my AppDelegate as I want it to be called first when the app starts (and then every x seconds which I will implement later).

plotParkingLots works fine if I call it through my MapViewController's viewDidLoad, but when I call it from AppDelegate, it doesn't work.

I know that it is called but when I switch to my map view, no annotation is shown!

MapViewController.h

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

#define METERS_PER_MILE 1609.344

@interface MapViewController : UIViewController <MKMapViewDelegate>

@property (strong, nonatomic) IBOutlet MKMapView *mapView;

- (void)plotParkingLots;

@end

MapViewController.m

- (void)plotParkingLots {
    NSString *url = [NSString stringWithFormat:@"http:/localhost/testes/parking.json"];
    NSData *jsonData = [NSData dataWithContentsOfURL: [NSURL URLWithString:url]];

    if (jsonData == nil) {
        UIAlertView *alertBox = [[UIAlertView alloc] initWithTitle: @"Erro de conexão" message: @"Não foi possível retornar os dados dos estacionamentos" delegate: self cancelButtonTitle: @"Ok" otherButtonTitles: nil];
        [alertBox show];
    }
    else {
        NSError *error;
        NSDictionary *json = [NSJSONSerialization JSONObjectWithData:jsonData options:NSJSONReadingMutableContainers error:&error];

        NSArray *parkings = [json objectForKey:@"parkings"];
        for (NSDictionary * p in parkings) {
            Parking *annotation = [[Parking alloc] initWithDictionary:p];
            [_mapView addAnnotation:annotation];
        }
    }
 }

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

    static NSString *identifier = @"Parking";
    if ([annotation isKindOfClass:[Parking class]]) {
        MKPinAnnotationView *annotationView = (MKPinAnnotationView *) [_mapView dequeueReusableAnnotationViewWithIdentifier:identifier];
        if (annotationView == nil) {
            annotationView = [[MKPinAnnotationView alloc] initWithAnnotation:annotation reuseIdentifier:identifier];
        } else {
            annotationView.annotation = annotation;
        }

        annotationView.enabled = YES;
        annotationView.canShowCallout = YES;
        annotationView.image=[UIImage imageNamed:@"car.png"];

        return annotationView;
    }

    return nil;    
}

AppDelegate.m

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    // Override point for customization after application launch.
    [[MapViewController alloc] plotParkingLots];

    return YES;
}

Upvotes: 0

Views: 377

Answers (1)

Craig
Craig

Reputation: 8294

You're not talking to the MapViewController that is displayed to the user. In your AppDelegate you momentarily allocation a MapViewController, plot the parking lots, then abandon that MapViewController and never use it again.

You'll need to keep a handle to that controller so that when the user presses something to make that viewcontroller get displayed it is the same one that has just plotted the parking lots.

Upvotes: 1

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