Touch Screen Edge Cases

While fiddling with the Nexus One last week, I was incredibly annoyed at how many times I accidentally tapped the Home button while trying to tap the space bar on the software keyboard. I posted this little note on Twitter about the issue: “DON’T EVER PUT BUTTONS FLUSH WITH THE BOTTOM OF A SOFTWARE KEYBOARD. PEOPLE WILL ACCIDENTALLY TAP THEM AND BE PISSED” (http://bit.ly/8MUQL2).

At the time, I felt something was fundamentally wrong with the “hardware buttons” (really just an extension of the touch sensitive area) being flush with the edge of the screen, but it didn’t dawn on me until today the particular problem it presents.

The unused edges of a touch screen serve to expand the “target” of any button positioned against them.

While typing on the iPhone I’ve been subconsciously tapping slightly below the bottom row of the software keyboard because it requires less precision. My fingers were using that muscle memory while typing on the Nexus One keyboard. By putting the “hardware buttons” flush with the bottom of the screen, the Google/HTC engineers made the bottom row of the software keyboard (or any other button at the bottom of the screen) inherently more difficult to use.

Here’s a video example of Palm having made the exact same mistake on the PRE: http://bit.ly/8gCqEO (starts around 00:40)

There are so many subtle things that Apple got right with the iPhone. Whether or not there was ever an iPhone prototype with more “hardware buttons” or a “gesture area” we’ll never know, but I do know that being able to visually define and re-define all aspects of an app’s UI within that 320x480 screen has let to some incredible fun and innovation.