HTML5 mobile apps with RhoMobile
It seems that every customer I talk with these days are chasing the elusive write once run anywhere. Typically, the best answer is to go with HTML5/JavaScript because it is the most ubiquitous option across devices. One recent customer that I was working with has a fleet of Windows Mobile 6.5 devices with native applications that they are looking to upgrade to a more modern hardware device. Unfortunately, the browser on the Windows Mobile 6.5 devices do not support HTML5, or the necessary app packaging mechanism to keep their employees from using the device browser to access non-company web solutions.
Initially, we looked at using the popular PhoneGap solution for packaging applications built with HTML. While PhoneGap does have wide support for a number of platforms, they do not support the older Windows Mobile operating system.
Motorola does offer a solution that does work with Windows Mobile as well as newer platforms, including iOS, Android, and Windows Phone 7+. Their RhoElements suite provides the ability to build mobile applications either using Ruby or even plain HTML5. They offer a descent tutorial for getting started including a sample which can access the native barcode scanner on the Motorola devices.
So how are they able to support HTML5 on a device based on an OS with IE6? They have essentially ported WebKit to Windows compact allowing them to render HTML5 reasonably well. This appears to work fairly well for relatively simple layout options and does appear to support relatively complex JavaScript frameworks, including jQuery, backbone, underscore, require.
One issue that I did run into is the performance can leave a bit to be desired. Don’t expect to see V8 level performance from their JavaScript interpreter. They are still restricted by the memory and operating system limitations that come with an OS and hardware that are over 5 years old. For example, I tried to implement the iScroll plug-in to allow for flick and finger drag support over a list of items. Just adding 100 items to the demos that come with iScroll brought the UI to a screaming halt (actually, the UI paused briefly and then would immediately scroll to the bottom of the list regardless of how far I swiped with my finger). This caused the list to become utterly unusable.
I did find the RhoMobile platform to be an interesting option for Windows Mobile and beyond, you do have to be careful what you try to get it to do. If you’re not careful, your result may still lead you down the road of write once, suck everywhere.