Ever since the introduction of the Nexus 7 last week many had thought that Google had decided to set their new tablet to use the 'phone' layout of Android 4.1 since the 'Home' screen is rigidly set as a portrait orientation with the notifications bar on top. A couple of days ago we showed a hack that had been developed to trick the Nexus 7 into showing a more 'tablet'-like landscape view for the Home screen. The 'hack' artificially changed the screen size in a system file to make the software think the device was larger than 7 inches and therefore trigger the 'tablet' UI which gave a landscape orientation with the notifications on the bottom right. So is the Nexus 7 set in 'phone' mode? Well...no. We now know that isn't quite the case.
JR Raphael, over at ComputerWorld has spoken to some techs at Google and has since learned that there are actually THREE different screen layouts in Android 4.1 depending on the size of screen you are using. There's a 10 inch layout which is landscape based. There's a phone layout for small screens with a portrait orientation. Then there's the 7 inch layout...which is a sort of a combination of the two. Each is designed to maximize that particular form factor.
In the 7 inch Android 4.1 layout the Home screen is indeed in portrait mode but some applications will customize themselves to best use the screen real estate depending on the orientation of the tablet. An example below is the Gmail application. When in portrait mode and held vertically you'll see a single pane display but when oriented horizontally, you'll have a dual pan landscape display like this:
Now, we know what you must be thinking. Isn't this going to cause 'fragmentation' if different devices have to have different layouts for the same app? Well...no. You see if an app is programmed correctly using Jelly Bean's tools, the OS actually handles the changes 'on the fly' automatically. That's one of the beauties of Android 4.1. It has been specially designed so that developers can have one app with multiple screen size customizations depending on the screen. There's no need to have separate apps. Here's how Android enginner Dianne Hackborn explains it:
For developers, when designing your app to scale up from its phone UI, this mostly means you should pick the break point at which any major change in your layout should occur and let the layout managers take care of all of the sizes in-between. ...
Android's density scaling was designed to be able to support arbitrary densities, by including the concept of density in all of the UI specifications of the application (bitmaps, measurements, etc) and using layout managers for final pixel-accurate placement of UI elements. ...
You don't need to supply bitmaps for every possible density; Android will scale your bitmaps (typically when they are loaded) to match the current density.
So in a nutshell: 7 inch tablets are not using a 'phone' UI. They are using a unique combination of elements...some taken from the tablet UI, some from the phone UI and some unique to the 7 inch form factor. All as part of the goal of maximizing each screen size to its best potential.