如何在ViewDidLoad之前运行委托方法

Question

• 1. ViewControllerA sent ViewControllerB a key with delegate

• 2.When ViewControllerB been loaded the key value is correct, but I need to use the key for viewDidLoad

So the problem is:How can delegate method run first so i can use the key in viewDidLoad ?OR:is there a way to use this key while viewDidLoad if can't make delegate run before viewDidLoad ?

Answer 1

Write an initialiser method in ViewControllerB something like initWithNibName:bundle:key:delegate: Something like shown below

- (id) initWithNibName:(NSString *)nibNameOrNil
            bundle:(NSBundle *)nibBundleOrNil
               key:(NSString*)aKey
          delegate:(id) aDelegate
{
    self=[super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
    if(self) {
        // Save aDelegate and aKey as properties
    }
    return self;
}

After init the viewDidLoad will get called where you can use these property values.

Cheers!
Amar.

Answer 2

Why can't you do something like this:

lets say that your key is a String,

1) in your ViewControllerB.h add

@property (nonatomic, copy) NSString *keyFromParent;

- (id)initWithNibName:(NSString *)nibNameOrNil WithKey:(NSString *)key bundle:(NSBundle *)nibBundleOrNil;

2) in your ViewControllerB.m replace your initWithNibName method with

- (id)initWithNibName:(NSString *)nibNameOrNil WithKey:(NSString *)key bundle:(NSBundle *)nibBundleOrNil{
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
    if (self) {
        self.keyFromParent = key;
    }
    return self;
}

3) When you present the ViewControllerB from the ViewControllerA do it like this,

ViewControllerB *controller = [[ViewControllerB alloc] initWithNibName:@"ViewControllerB" WithKey:KEY_FROM_DELEGATE bundle:nil];
[self presentViewController:controller animated:YES completion:nil];

4) Now you can use the keyFromParent which is the value passed from the ViewControllerA in the viewDidLoad method of the ViewControllerB

Hope this answer would help you!!

Answer 3

If you just want to send a variable value to ViewControllerB from ViewControllerA, then create property of that Variable in ViewControllerB with readWrite authority and assign it in ViewControllerA just before navigating to ViewControllerB.

if it is string variable to pass write in viewControllerB.h

@property (nonatomic, retain) NSString *variableName;

and in ViewControllerA when you are navigating to viewControllerB

viewControllerB *obj = [[viewControllerB alloc] initWithNibName:@"viewControllerB" bundle:nil];

obj.variableName = @"Your Value";
[self.navigationController pushViewController:obj animated:YES];
[obj release];