AppDelegate.h

@protocol NavBarDelegate <NSObject>
@optional
- (void)changeDashboardButton :(NSString*)fromSegue;
@end
 
@property (nonatomic,strong) id<NavBarDelegate> navbarDelegate;

NavigationBar.h

@interface NavigationBar : UIView <NavBarDelegate> {
    
    AppDelegate* appDelegate;
 
}

NavigationBar.m

-(id) initWithFrame:(CGRect)frame{
    if (self = [super initWithFrame:frame])
    {
        appDelegate = (AppDelegate *)[[UIApplication sharedApplication] delegate];
        appDelegate.navbarDelegate = self;
    }
    self.frame = frame;
    return self;
}
 
- (void)changeDashboardButton :(NSString*)data{
    NSLog(@" data %@",  data);
}

NavigationViewController.m

- (void)viewDidLoad {
    [super viewDidLoad];
    
    appDelegate = (AppDelegate *)[[UIApplication sharedApplication] delegate];
    
    [self setUpView:@"Yo"]; //Totally works
    [self test];//Totally breaks unrecognized selector sent to instance 0x7869d8d0
}
 
- (void) setUpView:(NSString*)sData{
  [appDelegate.navbarDelegate changeDashboardButton:sData];
}
 
-(void)test {
    [appDelegate.navbarDelegate changeDashboardButton:@"Hello"];
}