That changes with Android 4.0, known by the code name "Ice Cream Sandwich." Devices that ship with the new version must bundle an unmodified version of Holo, Google's new default theme. Vendors are still free to include their own themes, but Holo must always be available. To coincide with the release, Google has issued a set of user experience guidelines to help developers make their apps play nice with the new standard UI.
Whose UI will be a winner?
These changes give mobile app developers much to ponder. For starters, will they be successful? Bold product design can sometimes backfire. The clearer the distinction between your product and those of your competitors, the more aggressively you steer your potential customers -- either toward your product or away from it.
Microsoft knows this as well as anyone. For example, the Zune was a perfectly serviceable portable audio player, but Microsoft's decision to wrap it in brown plastic mystifies analysts to this day. There's a chance history could repeat itself with Metro.
For its part, Microsoft claims to have based its recent UI decisions on extensive user research. Still, some critics complain that Metro seems to be a poor fit for the PC desktop -- myself among them. If Metro wears out its welcome on Windows PCs, that negative sentiment could harm sales of Windows smartphones and tablets.
Equally important for developers, the more the leading smartphone platform UIs differ from one another, the more effort is required to write apps that function comparably across all of them. Dialog boxes, screen transitions, and gestures that are appropriate for one platform might be all wrong for another. Coding the same app for three or four different sets of user interface guidelines adds yet another layer of cost and complexity to cross-platform app development -- as if it wasn't already hard enough.
Native apps trump the mobile Web
It's easy to see why. The Web has never presented anything even close to a consistent UI. Buttons, menus, preferences, dialogs, fonts, and icons all differ wildly. Each site is like a completely new platform unto itself.
It's very likely that this cacophony is a big part of why users have responded so well to native smartphone apps. Users crave consistency, particularly with lightweight, easy-access devices like smartphones and tablets. The more platform vendors encourage developers to code their app UIs to uniform standards, the more attractive those apps will become when compared to the Web.
For users this is undoubtedly a good thing, but for developers it's troubling. It's yet another way in which the mobile development market is becoming increasingly fragmented. The more distinctive the mobile platforms become, the more developers are forced to become specialists to deliver successful apps for them. Smartphones may still all function pretty much alike, but it's getting harder and harder to avoid falling into the vendors' walled-garden ecosystems.
This article, "Mobile UIs: It's developers vs. users," originally appeared at InfoWorld.com. Read more of Neil McAllister's Fatal Exception blog and follow the latest news in programming at InfoWorld.com. For the latest business technology news, follow InfoWorld.com on Twitter.