UX in the wild: Amazon's Kindle app

I discovered a rather nifty UI mechanism a few days ago: a usable, elegant, and minimal control for locking and unlocking screen rotation. It was in Amazon's Kindle app on my Galaxy Nexus (though a quick check shows that it's in their iOS app as well).

In most apps I've seen, developers leave auto-rotation management up to the operating system. That is, there is no way to specify your auto-rotation preferences in the app itself -- it just honors the device's main settings. There is a small class of apps who manage it themselves, though -- mostly news or e-readers where users might want to read lots of text while lying on their side. For most of these, the user can lock or unlock the auto-rotation from some settings menu. This placement has some obvious UX drawbacks:

• Unless the user explores the settings menu, he may not know that the option even exists. This could make him stop using the app. 
• It's not easy to toggle on and off quickly -- with several taps required, it can be frustrating and possibly stop the user from using the app.
• It's impossible to know the current state of the rotation lock without checking. This is especially frustrating on older devices which have some lag before the rotation kicks in. Once the state is learned, then the user must navigate back into a menu and change the setting if necessary.

The rotation-lock mechanism in the Kindle app, however, solves all these problems in a simple way: Whenever you rotate your device, a little lock icon appears in the corner that is either locked or unlocked to reflect the auto-rotation state. If you wish to change the state, tapping the lock causes the rotation to adjust immediately. After a few seconds, the icon disappears.

This feature is easy to discover, easy to toggle, and easy to check. While it may have some small drawbacks for certain types of users, it appears to be an across-the-board improvement on the way this option is usually accessed and presented. It's really nice to see novel UI mechanisms continue to spring up in mobile -- and especially from big companies. Great job, Amazon!

(Note: I'm not sure how long this feature has been around because I usually disable auto-rotate in the entire device. It's new to me, though, and good UI makes me happy.)


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