How many buttons should a phone have?
Apple’s genius of simplicity gave us a phone with just one physical button. Whereas the Android phones have many more:
This set me thinking — what’s the right number of buttons for a touch-screen phone to have?
We obviously need a home button, for multiple reasons: returning to the home screen is something we do all the time, and you want to do it at one shot rather than backing out from a deep hierarchy step by step. Also, you need at least one button controlled by the OS, to move out of a hung app.
The back button that Android phones have is also useful, because that’s also a frequently performed action, for which a hardware button helps, and you wouldn’t want each app to express the same idea in slightly different ways. And, importantly, Android lets you move from one screen to another without regard to what apps they are part of. For instance, from Email, you can click on Attach to launch Gallery, then click on an image or video to see it full-screen. Pressing back takes to the gallery view, and pressing back again takes you back to email. Since each app controls the screen entirely without regard to the context in which it’s invoked, you need a physical back button to transition between screens without regard to which apps they are from. I always find it jarring that on the iPhone, if you’re deep within an app, you can progressively come out of the hierarchy by tapping the button at the top-left, but only till you reach the app’s main screen. The system should not enforce such a strong separation between apps — going back is a general action that makes sense from the main screen of an app, and between apps as in the Android example above.
I hate the menu key on Android phones. Better to put the actions right there on the screen where the user can see it. The first hour or so of using Android was very frustrating to me, since I seemed stuck, with no way to navigate out of the current screen. In addition to having a smoother learning curve, or rather none at all, putting the actions on screen saves one button press — the set of available actions isn’t hidden from you till then.
Some actions are so frequently used that putting them one level of indirection away is plain wrong, in that it takes the user more clicks to do the same task. If there are too many actions to show on screen at once, take the user to a second screen. Which is what the menu is, to some extent — you see only content on screen, till you press the menu button, at which point you see navigation. It would be more intelligent to mix and match content and navigation, showing the most important ones from each, and take the user to a second screen with additional content and actions.
Unfortunately, it looks like most Android phones will be stuck with a menu button, for compatibility and other reasons.
Then, Android has the green and red buttons, to make a call and to end it. Not being a heavy phone user, I would prefer on-screen keys for these. Having fewer buttons reduces the cognitive load and makes the phone easier to use as a data device.
Update: The same goes for the trackball. It’s just not needed. I have fat fingers, and I click on links in web pages without trouble. The trackball makes it slightly harder for developers because widgets should now handle a touch mode (where there’s no focus) and a non-touch mode.
