CODEWITHSUNDEEP
iphoneobjective-ccocoa-touchmodel-view-controllerparent-child
n.evermind
n.evermind

Reputation: 12004

iPhone: How can a child tell his parent to do something

OK, I have a RootViewController.m and defined a method in there:

-(void)doSomethingParent
{
    NSLog(@"Parent is doing something after child has asked");
}

I then added a childViewController.view like so:

if (self.child == nil) {

    ChildViewController *cvc = [[ChildViewController alloc]
                                initWithNibName:nil bundle:nil];
    self.child = cvc;
    [cvc release];

}    
[self.view insertSubview: child.view atIndex:0];

Now, I thought it would be very useful indeed if I could call my doSomethingParent method from the child. So I thought I would do it like this:

 @implementation ChildViewController
@class RootViewController;


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

    [super doSomethingParent];

}

But xCode tells me that "-doSomethingParent" not found... but I put @class in there?! Shouldn't it find it? I don't want to import the whole thing as I thought @class would be sufficient to let the child know that the parent has a method called doSomethingParent...

I'd be very grateful for any suggestions. Thanks in advance!

Upvotes: 1

Views: 1280

Answers (3)

hotpaw2
hotpaw2

Reputation: 70673

Easy way (perhaps not the best way):

self.child = cvc;
cvc.myParent = self;  // give the child a reference to its parent

Upvotes: 0

Bourne
Bourne

Reputation: 10302

Set rootViewController object as the delegate of an object of childViewController type. And use that delegate from ChildViewController to pass messages to RootViewController.

Inside RootViewController, when you create your ChildViewController object do:

childViewController.delegate = self;

And in ChildViewController, when you want to pass a message then pass it to RootViewController as:

[delegate doSomething];

In your ChildViewController.h interface, declare an ivar:

id delegate;

Then use @property (in .h) and @synthesize (in .m) for getter and setter.

Then do the above.

Upvotes: 4

Youssef
Youssef

Reputation: 3592

super is a reference to it's superclass, not the parent view controller. You will have to keep a reference to RootViewController and pass the message to it...

...Or code a protocol and set your RootViewController as delegate of the child, so the child would be able to pass messages to RootViewController.

I prefer the second way.

Upvotes: 3

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