Why is my delegate method not being called? - iphone

Question

In this code I'm attempting to pass an array from one tab view to another using protocols. The method itself is a simple get method with one line returning an a mutableArray. Within it's own class it works, within this class it is not even called.
- (void)viewDidLoad
{
[super viewDidLoad];
myLocationEntityArray = [[NSMutableArray alloc] initWithArray:[[self delegate] getMyLocationEntityArray]];
}
The header file for the class receiving the data:
#import <UIKit/UIKit.h>
#import <MapKit/MapKit.h>
#import <CoreLocation/CoreLocation.h>
#protocol CoreDataDelegate;
#interface ListTableViewController : UITableViewController
{
NSManagedObjectContext *managedObjectContext;
NSMutableArray *myLocationEntityArray;
id <CoreDataDelegate> delegate;
}
- (NSMutableArray *)fetchCoreData;
#property(nonatomic, retain) NSManagedObjectContext *managedObjectContext;
#property(nonatomic, assign) id <CoreDataDelegate> delegate;
#property(nonatomic, retain) NSMutableArray *myLocationEntityArray;
#end
#protocol CoreDataDelegate
//- (NSMutableArray *) fetchCoreData;
- (NSMutableArray *) getMyLocationEntityArray;
#end
The top of the header file sending the data:
#interface MapViewController : UIViewController <CLLocationManagerDelegate, CoreDataDelegate>

Answer 1

First you should change your procotol like this :
#protocol CoreDataDelegate
//- (NSMutableArray *) fetchCoreData;
- (void) getMyLocationEntityArray:(NSMutableArray *)entityArray;
#end
You set your MapViewController to responds to your protocol CoreDateDelegate. So, I suppose you alloc your ListTableViewController inside the MapViewController. If that is the case, you need to do this :
// MapViewController.m
...
ListTableViewController *listVC = [[ListTableViewController alloc] init];
listVC.delegate = self;
// display your listVC
...
// Somewhere in your code of MapViewController.m
- (void) getMyLocationEntityArray:(NSMutableArray *)entityArray {
// do something with entityArray
}
EDIT
Following your comments, here is a simpler way to do what you want. NSNotification. It does not require protocol, and is easier to implement.
// In ListTableViewController.m
// In Init or viewDidLoad function
[[NSNotificationCenter defaultCenter] addObserver:self
selector:#selector(getEntity:)
name:#"GetEntity"
object:nil];
- (void)getEntity:(NSNotification *)notif {
NSArray *entityArray = (NSArray *)[notif object];
// do something with entityArray
}
// In dealloc or viewDidUnLoad function
[[NSNotificationCenter defaultCenter] removeObserver:self
name:#"GetEntity"
object:nil];
// In MapViewController.m
// theEntityArray to be defined
[[NSNotificationCenter defaultCenter] postNotificationName:#"GetEntity"
object:theEntityArray
userInfo:nil];
In few words, when you will post the GetEntity notification in MapViewController, it will call undirectly the -(void)getEntity: function of ListTableViewController