While Google doesn’t have to worry about app developers fleeing Android en masse, they might be concerned that developer interest appears headed in the wrong direction.

A new survey of more than 2,100 app developers released jointly by IDC and mobile development platform vendor Appcelerator Tuesday found that 78.6% of developers were interested in creating apps for Android smartphones during the first quarter of 2012, down from the 83.3% in Q4 of 2011 and down from around 87% in Q1 of 2011.

“Massive platform fragmentation is a big reason that we’re seeing this decline in interest,” says Mike King, a former Gartner analyst who now works as Appcelerator’s principal mobile strategist.  “If you look at all the other numbers such as Android smartphone market share it’s on the upswing, but for app developers it’s a real challenge.”

Even so, Android still easily generates the second-greatest level of interest among mobile developers, as only Apple generated more with 89% of developers saying they wanted to make apps for iOS.  And Android is nowhere near seeing the dramatic free fall in developer interest currently plaguing Research in Motion’s BlackBerry OS, which saw its developer interest plunge to 15.5% in the first quarter of 2012, down from 20.7% in the fourth quarter of 2011 and down from around 37% in the first quarter of 2011.

The key for Android shoring up developer interest will be whether it’s successful in unifying Android smartphones and tablets under the same version of its mobile operating system, thus creating far fewer uncertainties for developers.  Android 4.0 (“Ice Cream Sandwich”) was an important step in this direction as it was the first version of Android to be optimized for both tablets and smartphones.  All the same, King says that app developers aren’t yet embracing Ice Cream Sandwich with open arms.

“They’re somewhat lukewarm to Ice Cream Sandwich, they’re taking a wait-and-see approach,” he says.  “Whereas with Apple, they’re saying, ‘We know iOS and it’s relatively easy for us to build an application and deploy it.”

IDC and Appcelerator also found that Microsoft has been making progress in attracting mobile developers as 37% said they were interested in developing apps for Windows Phone 7 and Windows 8 tablets. 

In addition to its findings on developer interest in mobile operating systems, the IDC/Appcelerator survey found that HTML5, the programming langue pushed by Apple as an alternative to Adobe Flash for online video, has been making major inroads with app developers.  IDC and Appcelerator report that 78% of app developers surveyed say they “will integrate HTML5 in their apps” this year.  The firms say that this number is “much higher than industry observers had anticipated” even late last year.  The migration to HTML5 may have been accelerated by Adobe’s announcementlate last year that it planned to start using HTML5 for mobile going forward, relegating Flash to being a desktop video platform.

“HTML 5 is now universally supported on major mobile devices, in some cases exclusively,” Adobe said last year when it made its decision to adopt the standard.  “This makes HTML 5 the best solution for creating and deploying content in the browser across mobile platforms.”