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In my article on CoreText I mentioned that Apple left out some very useful methods from NSAttributedString, namely the ones that would allow you to create an attributed string from HTML. Now you would probably not want to create attributed strings from complex HTML documents, but use that for simple tasks like displaying one word in a different color or bold.

My first thought was that maybe I should make it a sellable component, but I dismissed this idea for two reasons:

1. there is a certain likelyhood that Apple will implement the missing functions in the next major SDK refresh
2. if I would get help from people who are more experienced in dealing with HTML parsing then this would benefit everybody involved

So I posted the question on Twitter as to where to put the shared code. The response was a resounding GitHub (one mention of Mercurial and Assembla each). So far I had put off dealing with GitHub, because – in contrast with many other iOS developers – I happen to very much like Subversion integration in Xcode.

Read on to learn how to get started.

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I am building a category for NSAttributedString that will allow me to make attributed strings from HTML code. For coloring the text there are two methods in HTML, via the deprecated font tag and via style. Both use color names or hex to describe the color.

The W3C knows 147 color names, clearly too many to type in manually. So I used a bit of shell script magic to hammer this into Objective-C. Then I also needed an elegant method to make regular UIColor objects from a hex string.

Both I am sharing in this article. These methods are invaluable if you are dealing with web people who are used to specifying colors this way. Also it might be more intuitive if you can specify colors in hex format yourself. That is, if you are a geek who is used to thinking in the hexadecimal system.

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Before the iPad was released you had basically two ways how to get text on screen. Either you would stick with UILabel or UITextView provided by UIKit or if you felt hard-core you would draw the text yourself on the Quartz level incurring all the headaches induced by having to mentally switch between Objective-C and C API functions.

As of iOS 3.2 we gained a third alternative in Core Text promising full control over styles, thread safety and performance. However for most of my apps I did not want to break 3.x compatibility and so I procrastinated looking at this powerful new API. Apps running only on iPads could have made use of Core Text from day 1, but to me it made more sense supporting iPad via hybrid apps where the iPhone part would still be backwards compatible.

Now as the year has turned the adoption of 4.x on all iOS platforms is ever more accelerating. Many new iPads where found under the Christmas tree and by now even the most stubborn people (read needing 3.x for jailbreaking and sim-unlocking) have little reason to stick with 3.x. Thus we have almost no incentive left to stick with 3.x compatibility. Yay!

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