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Jonathan.
Jonathan.

Reputation: 55534

Storyboard relationship in iOS

I'm attempting to use the new Storyboard feature, however I am confused about Storyboard Relationships? How are they different to IBOutlets?

Also how can I add my own relationship, to my own UIViewController subclass?

I have tried looking in the documentation but can't find much about them.

Upvotes: 8

Views: 11836

Answers (3)

Simon
Simon

Reputation: 9021

I wrote a few tutorials on how to use storyboards over on my site...

Part 1 of tutorial

Part 2 of tutorial

Perhaps that will help a little bit? In essence, the Segue relationships provides an identifier for the link between two items on your storyboard. You can use these identifiers to manage how things work.

Upvotes: -1

James Snook
James Snook

Reputation: 4093

Create a subclass of the UIStoryboardSegue like this:

@implementation JTARelationshipSegue

- (void)perform
{
  return;
}

@end

Make a custom segue between your two objects and set the class as JTARelationshipSegue. In your view controller make the view controller perform the segue like this:

- (void)viewDidLoad
{
  ...
  [self performSegueWithIdentifier:@"addChild" sender:self];
}

You need to have set the segues identifier in interface builder to addChild.

Impement prepareForSegue:sender so that it adds the segues destination view controller as a child of the current view controller, like this:

- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
  UIViewController *destination = [segue destinationViewController];
  [self addChildViewController:destination];
  ...
}

You will need to have a different segue identifier for each child that you want to create (or another way of identifying the specific view controller.

This will make your storyboard file look prettier, and more readable, however you may do better to just load your other view controllers and add them as children in your view did load method:

- (void)viewDidLoad
{
   [self addChildViewController:
         [[self storyboard] 
          initiateViewControllerWithIdentifier:@"myIdent"]];
...
}

Upvotes: 1

lol
lol

Reputation: 4200

The way I understand it is: relationships are iOS's way of representing a 'parent-child' relationship and while that does seem quite recursive, an example of parent-child relationship is a UIViewController Container containing a UIViewController.

That's the theory anyway -- it's better understood using the UINavigationController. It is called a 'container' because it contains as many regular UIViewControllers in a 'stack' metaphor so you can do your normal UITableView drill downs and pop offs.

The key point is that the segue between UINavigationController and the first UIViewController in your stack, there is a 'relationship' while the segue between all the rest of the UIViewControllers is just a regular push segue.

The same thing is evident in the UISplitViewController -- it needs two view controllers (sometimes called content view controllers) from launch and these are connected up between the parent UISplitViewController (the container) and two regular (content) view controllers

(thus relationships are not like IBOutlets, but more like segues -- they are even in the 'segues' category of the standard view controller containers)

Now - we aren't allowed to subclass the standard view controller containers, but we are allowed to create custom view controller containers, but I can't for the life of me define a relationship in my custom view controller container!!!!!!!!!!!

so: "can I use them in my own controllers?" the answer is yet unknown (to me at least, and the documentation is thin at best)

Upvotes: 9

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