Comments on: How To Extend Objective-C Classes With Categories http://howtomakeiphoneapps.com/2009/11/how-to-extend-objective-c-classes-with-categories/ Get Started with Cocoa-Touch and iPhone Programming today! Thu, 26 Aug 2010 14:15:25 -0400 hourly 1 http://wordpress.org/?v=3.0.1 By: mattjdrake http://howtomakeiphoneapps.com/2009/11/how-to-extend-objective-c-classes-with-categories/#comment-396 mattjdrake Tue, 24 Nov 2009 20:12:27 +0000 http://howtomakeiphoneapps.com/?p=1614#comment-396 @webXL - you can use sub-classing and categories for similar problems and the difference is pretty subtle in a lot of ways. It is not really required and you could do a similar thing if you sub-classed NSString and used that object in place of a NSString object. Essentially though, the main thing is that when you are using categories you don't need to worry about replacing your NSString objects with a subclassed version of NSString. This way, when you already have objects in play (such as the text property of my UITextView) you can simply import the category and you have the functionality available to you automatically. @webXL – you can use sub-classing and categories for similar problems and the difference is pretty subtle in a lot of ways. It is not really required and you could do a similar thing if you sub-classed NSString and used that object in place of a NSString object.

Essentially though, the main thing is that when you are using categories you don’t need to worry about replacing your NSString objects with a subclassed version of NSString.

This way, when you already have objects in play (such as the text property of my UITextView) you can simply import the category and you have the functionality available to you automatically.

]]> By: webXL http://howtomakeiphoneapps.com/2009/11/how-to-extend-objective-c-classes-with-categories/#comment-395 webXL Tue, 24 Nov 2009 19:24:01 +0000 http://howtomakeiphoneapps.com/?p=1614#comment-395 Nice tutorial, but I'm not sure I understand the differences between subclassing and categories. Are categories used just so you don't have to instantiate a subclassed object to get added functionality? Or is it required in this instance because the text component can only work with an NSString? Nice tutorial, but I’m not sure I understand the differences between subclassing and categories. Are categories used just so you don’t have to instantiate a subclassed object to get added functionality? Or is it required in this instance because the text component can only work with an NSString?

]]> By: mattjdrake http://howtomakeiphoneapps.com/2009/11/how-to-extend-objective-c-classes-with-categories/#comment-392 mattjdrake Mon, 23 Nov 2009 19:47:48 +0000 http://howtomakeiphoneapps.com/?p=1614#comment-392 @hawk - awesome I'm glad that you liked it. BTW: Did you find Cocoa Design Patterns to be a good read? That one is on my list and I have a feeling that it would be really helpful... @hawk – awesome I’m glad that you liked it.

BTW: Did you find Cocoa Design Patterns to be a good read? That one is on my list and I have a feeling that it would be really helpful…

]]> By: hawk http://howtomakeiphoneapps.com/2009/11/how-to-extend-objective-c-classes-with-categories/#comment-391 hawk Mon, 23 Nov 2009 19:25:31 +0000 http://howtomakeiphoneapps.com/?p=1614#comment-391 This post came in very handy today. Why? Well because I finished reading about Categories in the Cocoa Design Patterns. So it was since to see it in action. Thanks again! This post came in very handy today. Why? Well because I finished reading about Categories in the Cocoa Design Patterns. So it was since to see it in action. Thanks again!

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