Simple custom delegate not getting called - ios

Question

Let's see if you guys can find the error here... because I'm really stuck right now.
DBManager.h
#protocol DBManagerDelegate <NSObject>
#optional
- (void) managerDidFinishUpdating:(id)controller;
#end
#interface DBManager : NSObject
#property (strong, nonatomic) id <DBManagerDelegate> delegate;
- (id) init;
#end
DBManager.m
#import "DBManager.h"
#implementation DBManager
- (id)init {
self = [super init];
if (self) {
[[self delegate] managerDidFinishUpdating:self];
}
return self;
}
UIViewController.h
#import <UIKit/UIKit.h>
#import "DBManager.h"
#interface DBViewController : UIViewController <DBManagerDelegate>
#property (nonatomic, retain) DBManager *manager;
#end
UIViewController.m
#import "DBViewController.h"
#implementation DBViewController
- (void)viewDidLoad
{
[super viewDidLoad];
_manager = [[DBMataroManager alloc] init];
[_manager setDelegate:self];
}
- (void)managerDidFinishUpdating:(id)controller {
NSLog(#"Manager did finish");
}
#end

Answer 1

You should write like this,
- (id)initWithDelegate:(id)delegate {
self = [super init];
if (self) {
_delegate = delegate;
[_delegate managerDidFinishUpdating:self];
}
return self;
}
//Call it as follow
_manager = [[DBManager alloc] initWithDelegate:self];
[_manager setDelegate:self];

Answer 2

The delegate method managerDidFinishUpdating: is called within init. You set yourself as the delegate after calling init.
Maybe an initWithDelegate: method would help.
- (instancetype)initWithDelegate:(id< DBManagerDelegate>)delegate {
self = [super init];
if (self) {
self.delegate = delegate;
[self.delegate managerDidFinishUpdating:self];
}
return self;
}

Answer 3

You are trying to use the delegate in the init, but you have not set it until the next statement. The only way to do this would be to set the delegate as part of you init statement.
-(id)initWithDelegate:(id<DBManageDelegate>)delegate {
if ((self = [super init])) {
self.delegate = delegate;
if (delegate && [delegate respondsToSelector:#selector(managerDidFinishUpdating:)]) {
[delegate performSelector:#selector(managerDidFinishUpdating:) withObject:self];
}
}
return self;
}
But if you plan to do some additional things before the manager is updated I would suggest you move all of that outside of the init, perhaps into an updateManager function like this
-(void)updateManager {
// Do the stuff that updates your manager here
if (delegate && [delegate respondsToSelector:#selector(managerDidFinishUpdating:)]) {
[delegate performSelector:#selector(managerDidFinishUpdating:) withObject:self];
}
}
..later in your app
_manager = [[DBMataroManager alloc] init];
[_manager setDelegate:self];
[_manager updateManager];