Why is this happening?
When a phone is being designed, it's probably not being handled by people with an interest in Android unity. Button placement is either of little importance, or they have a specific idea on how they want them. It's possible everyone has their own ideas about what's most usable, and if they think they have the most desirable arrangement, it might be seen as a differentiating factor. If it works well in testing, the buttons will probably stay in whatever order was originally decided on. Design teams even vary within a company, so consistency isn't even guaranteed from one generation to the next (see: Droid 1 vs 2).
Certainly different manufacturers aren't going to collaborate ahead of time and decide on a layout. These designs are done months before anyone outside the company sees them. Even if there was time, there's no advantage for Motorola to change their button order to match the new HTC phones. This means the consumer sees a number of layouts that some mid-level designer feels is the best layout. Of course, everyone that feels strongly about their design has the same opinion.
What Google can do
Google could easily come up with a standard button layout, and mandate that all phones use that same order, or maybe have two different options for different devices. Android is open, and can be used by anyone, but as mentioned above, Google has licensing relationships that could be of use here. Google holds the Google apps like Gmail, Talk, and Market as closed source. It's really the bait to get manufacturers to work with them instead of going it alone. Google doesn't have many restrictions, so adding one for button order should be fine.
What's the most efficient layout?So let's say that Android phones were going to use a standard button layout. The home, menu, back, and search buttons all have slightly different usage patterns, so depending on the phone type, one pattern might be better than another. It comes down to how you will be holding the phone, so what we're talking about is phones with landscape keyboards, versus those with no keyboards. The ideal layout might vary, but we're going to search for a consensus. Let's look at the slate phones first.
We feel that the two center spots are the easiest to hit. This is the area your thumb probably hovers over anyway. So it's best to keep the home and back buttons there. It's perfect for a quick tap to go back or bounce to the home screen. The two outside positions are less desirable real estate. Our suggestion is menu on the far left, and search on the far right. It's a little less convenient for righties to tap on the far right, and the search button is probably going to see the least amount of use for most people. Sorry lefties, you're outnumbered. Also, the search button has almost always been there.
So that's menu, home, back, and search for a slate phone. Samsung's Galaxy S phones (the non-international version) and the Droid X have this button order, and we think Samsung should have stuck with it rather than changing it up with the Nexus S.
When you turn the phone on its side and open the keyboard, the search button is suddenly really far away. That's fine, because almost all keyboards have a search button. A menu button is also common. Back is often missing from the keyboard, as is Home. So here's what we propose, the best layout in this circumstance has the back and search buttons on the left of the row, so that when using the keyboard, the buttons less likely to be present on the slide out, are closer and easier to tap. So that would be back, home, menu, search.
One layout to rule them all?So those are the two options we find most usable for the different form factors. But that doesn't necessarily mean Google should support two layouts. If they wanted to enforce one, we'd go with the layout we decided on for the non-keyboard phone. That was menu, home, back, and search. Even keyboarded phones are used in portrait mode much of the time.
Google could also help smooth over the differences between keyboarded and non-keyboarded phones by adding a second new requirement to the Android licensing agreement. Simply require manufacturers to include all four system buttons on the keyboard. We consider this more of an optional step, but it would be nice to see handset makers give us the keys.
The current ecosystem of system buttons is a little confusing for someone new to Android. While it is true people will adapt to their button layout eventually, they shouldn't have to. It would be an easy problem for Google to fix, but they have not shown any interest in it thus far. What do you think is the best order of buttons on an Android phone? How do you feel about the odd placement of the search button on the Nexus S?
Lead image via Flickr user johanl