Question

i am developing an iOS application. I have a controller : iPhonePopUpController, in this controller i have a xib like this image :

My question is, can i add an other xib to this Controller and loaded it when i need it or should i create a second controller to load my second xib ?

Answer 1

You can load anything from a XIB using:

[[NSBundle mainBundle] loadNibNamed:@"YourOtherXIB.xib" owner:someObjectThatWillTakeThePlaceOfFilesOwner options:0]

This line unarchive the XIB named YourOtherXIB.xib by creating the instances of the objects you have in your XIB, and then connect all the outlets and actions you defined in the XIB, and return the list of top-level objects.

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When you create a XIB whose File’s Owner is an UIViewController, typically you then initialize your UIViewController using code like this:

UIViewController* vc = [[[UIViewController alloc] initWithNibName:nibName bundle:bundle] autorelease];

What this code basically do internally is that it stores the nibName and bundle you provide in some internal property, and when it needs to load its view (especially the first time it needs to display it onscreen), it loads the view from the XIB using something like the line quoted above:

[bundle loadNibNamed:nibName owner:self options:0];

As you connected the view in your XIB to the view IBOutlet of the File's Owner‘s (which in that case is the self passed as an argument, namely the UIViewController itself), then the view property of your UIViewController will be populated with the view that has just been unarchived from the XIB. And that’s how UIViewController loads its view from a XIB file.

But of course you can do the same for your own classes and do not need your File’s Owner to be an UIViewController. Simply make your File’s Owner be whatever class fits your need, expose a custom IBOutlet from this class and connect it to your objects in your XIB.

• For example you can have a MyCustomClass class that declares an IBOutlet UIView* myOtherView;. Define the class of your File's Owner in your XIB to be of the class MyCustomClass, then bind the myOtherView outlet to the view to load from your XIB. Then in the code, create an instance of MyCustomClass and use the above loadNibNamed:owner:options: method by passing this MyCustomClass instance as the owner parameter
• Or you can reuse your UIViewController that loaded your primary XIB to load your other view from your secondary XIB too: simply add an IBOutlet UIView* otherView in your UIViewController subclass. In your first XIB, you will connect the view IBOutlet to your primary view but keep the otherView IBOutlet unconnected. In your second XIB, you will connect the otherView IBOutlet to your other view but keep view IBOutlet unconnected. When loading your UIViewController with the first XIB, the view property will be set to the view loaded from your XIB. Then if you want to lazy-load the otherView from the other XIB at a later time, simply call loadNibNamed:owner:options with OtherXIB.xib as the nib name and self as the owner. The OtherXIB will be unarchived and otherView property will be filled with that loaded view.