delegate is not respond

Question

I am trying to use delegation between two Viewcontrollers, but unfortunately my delegate doesn´t get fired. I hope somebody can help me fix the problem. I have a ViewContoller called MapBackgroundViewController and one called MapsViewController. The MapsViewController should be informed if the SegmentedControl of the MapsBackgroundViewController changes. (I actually try to implement something like the maps app on iPhone with patrial curl)

Here is part of my code:

MapBackgroundViewController.h

@protocol ChangeMapTyp <NSObject>
@required
- (void)segmentedControllChangedMapType:(MKMapType) type ;
@end


@interface MapBackgroundViewController : UIViewController{
IBOutlet UISegmentedControl *segmentedControl;
MKMapType mapType;
id < ChangeMapTyp> delegate;

}


@property IBOutlet UISegmentedControl *segmentedControl;

@property MKMapType mapType;

@property(strong)id delegate;

- (IBAction)segmentedControllChanged:(id)sender;

MapBackgroundViewController.m

@interface MapBackgroundViewController ()

@end

@implementation MapBackgroundViewController
@synthesize segmentedControl, mapType, delegate;


- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view.

[self setDelegate:self];

NSLog(@"%@",self.delegate);

}


- (IBAction)segmentedControllChanged:(id)sender {

if (segmentedControl.selectedSegmentIndex == 0) {
    mapType = MKMapTypeStandard;
}else if (segmentedControl.selectedSegmentIndex == 1) {
    mapType = MKMapTypeSatellite;
} else if (segmentedControl.selectedSegmentIndex == 2) {
 //   [self.delegate setMapType:MKMapTypeHybrid];
    mapType = MKMapTypeHybrid;
}


//Is anyone listening

NSLog(@"%@",self.delegate);

if([self.delegate respondsToSelector:@selector(segmentedControllChangedMapType:)])
{
    //send the delegate function with the amount entered by the user
    [self.delegate segmentedControllChangedMapType:mapType];
}

[self dismissModalViewControllerAnimated:YES];

}

MapsViewController.h

#import "MapBackgroundViewController.h"

@class MapBackgroundViewController;

@interface MapsViewController : UIViewController<MKMapViewDelegate,
UISearchBarDelegate,  ChangeMapTyp >{
 IBOutlet MKMapView *map;
}


@property (nonatomic, retain) IBOutlet MKMapView *map;


@end

MapsViewController.m (the below method for some reason gets never called)

 - (void)segmentedControllChangedMapType: (MKMapType) type{
    map.mapType = type;
 }

Answer 1

In MapBackgroundViewController you have set the delegate property to self, so the delegate is self - (MapBackgroundViewController) so when you perform the check if([self.delegate respondsToSelector:@selector(segmentedControllChangedMapType:)]) it returns NO, because self.delegate (which is self, which is MapBackgroundViewController), does not implement this method. If you want your MapsViewController to be the delegate, in your MapBackgroundViewController you must have an instance of MapsViewController (called myMapsViewController for example) and then set the self.delegate = myMapsViewController.