In other words, the interface code for an entire application, apart from a few dialog windows here and there, is expected to go into one single class. This code quickly becomes unmanageable and unmaintainable as the feature set changes and grows. It is natural to start to break this code up into logical groups of subcontrollers and to develop a system to manage and maintain these groups.

Very well written. If you aren't reading Cathy's blog yet, I think you should.

I haven't looked at the code in detail yet, but the results are impressive.

As you can see, it provides a spreadsheet control for Cocoa [...] provides column and row reordering, drag selection, and drag and drop functionality. The only feature that seems glaringly lacking right now is column resizing. I plan to add that in soon, but with classes gearing up for the quarter, I wanted to go ahead and get this out so it doesn't get lost in the dusty corners of my free time.

Whereas the basic animation does a simple linear interpolation the keyframe allows you to specify values at intermediate times so that you can fully control the value during the whole animation.

Yes, you read that right. Even "last Tuesday at dinner" works here

And there are some additional details:

In the end if you need to set the default value of a date attribute to the current date and time you'll need to subclass NSManagedObject. It's an easy thing to do so here it is...

...version 1.4 of the GData Objective-C Client Library adds support for [Google Contacts Data API and the YouTube API]. Any Mac program that creates video can easily let users upload the video to a YouTube account. Mac software can also now enable users to access or edit their Google account contacts.

And, as Greg Says "one more thing":

GData Objective-C Client Library is now compatible with the iPhone SDK as well. Perhaps you want your iPhone software to send photos to a Picasa Web Albums account, or keep a journal of phone calls automatically in Blogger. Maybe your iPhone application accesses a database of information from a Google Spreadsheet or from Google Base.

Very, very cool.

I've been working on this preference pane app and ran into the question - how do I build and run with the debugger attached?

This is a brand new blog, and already looks interesting. There are also posts on NSBundle, NSXMLDocument, and Network Reachability with the System Configuration framework.

Despite what you may have learned at one point, not all Foundation/Cocoa objects derive from NSObject. As an example, NSProxy is not derived from NSObject, so the foo2 pointer above would not be able to hold an NSProxy subclass, even though NSProxy does implement common methods like retain and release

ObjectiveYouTube is an Objective-C library written for uploading videos to YouTube licensed under the BSD license.

I don't think this a real replacement for model migrations, but it might help in certain situations, such as if you don't know the keys at compile time:

On the surface KSExtensibleManagedObject operates just like a normal managed object. But, if you call -valueForKey: or -setValue:forKey: it will happily return/store the value, rather than raise an exception as NSManagedObject would. For example, to support an extra property in your model named "foobar," without having to change the actual model in any way, you can just start calling [setValue:x forKey:@"foobar"] without worry.

(via Dan Wood)

Core Animation is obviously an enormous boon for user interface developers, but it has other uses too, such as visualization. There are many scientific applications for which Core Animation could be very useful. In the next few tutorials, I want to introduce Core Animation, and show its potential for scientific visualization. I won't be showing you how to create the CoverFlow effect, or reprogram the Front Row application, but will hopefully introduce you to a whole new way of looking at Core Animation.

Bill explains about using animated layers in 3D space, how Cocoa and Interface Builder avoid the trap of generated code stubs, the growing opportunities of internal fat-client apps on the iPhone platform, and opportunities in consulting for new rich user interfaces.

The default effect isn't too flashy. Make sure to try these via the "Effect" dropdown at the top right:

TransformWidgetProto
CatmullRom
EditableCurve
SummoningCircle
Paint
SkewTest
Polaroids
ImageTest

Somebody needs get on an authoring tool for this.

(via Gus Mueller)

This sample illustrates how to use the Scripting Bridge Framework to tell the Mail application to send an email message with optional attachments. The included readme file provides detailed discussion of the steps involved in creating this sample.

(thanks to Jeff De Luca)

This tutorial is about implementing a custom control class. The goal is not to explain how to subclass NSControl or NSCell, but how to think more generally about controls, what they are and how to implement one with an NSView subclass.