R – Possible to initialize an entire UITableViewController (or subclass) from a secondary NIB… not just a UIView

interface-builderiphonenibuinavigationcontrolleruitableview

Nearly all the UINavigationController examples out there show the use of initWithNibName:bundle: to load a NIB containing NOT an entire UIViewController (or subclass) but just a UIView, with the NIB's File's Owner Class property set to UIViewController (or the appropriate subclass) and its view outlet pointed at the UIView.

Why is this? Why can you not instantiate a full UIViewController (in particular, a UITableViewController) from a secondary NIB? And why do you even need to set the view outlet in IB? I don't understand the point of creating a blank white view which is going to be entirely ignored by a UITableViewController anyway.

In the MainWindow NIB, you can do both of the things that you seemingly can't do from a secondary NIB. You can setup a UINavigationController, and then within that you can setup a UITableViewController (or subclass). And you don't need to create an entirely superflous UIView object – rather helpful, since the whole point (I thought!) of a UITableViewController is that it creates and manages an associated table view for you using its delegate methods.

What is going on here? Am I being stupid? Is there some other way of doing what I want to? Or is there some logical reason for things being the way they are?

Best Answer

In IB create a new "Empty" nib and drag a "Table View Controller" into it from the Library.

Or am I misunderstanding the question?

Related Solutions

Iphone – UINavigationController NIB requires File’s Owner to have a view

I think you might not be understanding how the File's Owner is meant to be used in a NIB file. I've written up a response describing the file's owner under another question.

When you invoke this line:

[[MyNavCtrlrSubClass alloc] initWithNibName:@"MenuController" bundle:nil]

You create an instance of MyNavCtrlrSubClass, and tell it to load @"MenuController". Then in the MenuController.xib file, there is a second unrelated UINavigationController with things inside of it. When MenuController.nib is loaded at runtime, that second navigation controller will be created.

A second problem is that telling a UINavigationController to load a NIB file isn't really sensible because navigation controllers create and manage their own views. You really want to create the root view controller, and tell that view controller to load a NIB file.

Try this:

MyRootViewController *rootController = [[[MyRootViewController alloc] initWithNibName:@"AnotherViewController" bundle:nil] autorelease];
MyNavCtrlrSubClass *menu = [[MyNavCtrlrSubClass alloc] initWithRootViewController:rootController];

Where your XIB File looks like this:

File's Owner (Class set to MyRootViewController, view outlet connected to subsequent UIView)
UIView
- Subview A
- Subview B

After you're confortable with how all of this is working, you might also consider instantiating the navigation controller and root view controller in one XIB file like you were starting to do in the code you posted.

R – How does Interface Builder know about UIViewController’s view

The IBOutlet keyword is used to indicate that a property should show up in Interface Builder for classes that you write. Interface Builder internally has additional knowledge about system provided classes.

If you are working with Interface Builder on the desktop, rather than iPhone, you can write Interface Builder Plug-Ins to integrate your custom classes into the Interface Builder Library (This is not supported in Interface Builder for the iPhone). In writing a plug-in, the plug-in author provides "class description" files that declare this same actions/outlets information to Interface Builder as one achieves with the IBAction/IBOutlet keywords. You can read more about it in the Interface Builder Plug-In Programming Guide.

It works essentially the same way for system provided classes as it does for plug-ins.

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