The new Nexus 4 and Nexus 10 aren't just new Android devices — they're showcases for a new version of Android. Google's calling Android 4.2 "a new flavor of Jelly Bean" to reflect its essential similarity to Android 4.1, but there are some major new features in the mix.
The highlight is support for Miracast, an industry-standard Wi-Fi display sharing protocol that allows new devices like the Nexus 4 to stream audio and video to TVs. (Think AirPlay with broad industry support.) Miracast boxes for existing TVs are expected to go on sale from a variety of companies soon, and Google expects them to cost well under $99. And Miracast will soon be built directly into TVs, which is pretty exciting — LG's already committed to building it into all of its 2013 smart TVs. The technology worked quite well in our demo of Android 4.2 on a Nexus 4, and Google says developers can use each screen independently for big-screen gaming and other apps.
MIRACAST WILL SOON BE BUILT INTO TVS
Android 4.2 also includes a new gesture typing keyboard — you just slide your finger between each letter in a word and the keyboard figures out what you're trying to type. It's a lot like Swype, but it seemed a little bit faster and more accurate in our brief demo, and words are displayed above your finger as you move, so it's a little easier to know what's going on. The feature works well with Google's SwiftKey-like auto-prediction, which provides a list of words it thinks you might type next has you type — simply swiping "good" automatically predicts "morning," for example. It all makes one-handed typing extremely easy, although we're sure SwiftKey and Swype won't be too pleased.
Google's also using some of its Street View camera techniques for a new Android 4.2 panorama mode called Photo Sphere. The camera prompts you to line up and take overlapping shots of a scene, which it then stitches together to make an immersive panorama — just like Street View. You can view the resulting image as a flat file, but Android 4.2 and Google+ have built-in Photo Sphere viewers that let you move things around. (The file format is just regular .jpg with some embedded XML, so anyone can build a viewer, not just Google.) It's impressive stuff.
ANDROID 4.2 WILL SHIP ON THE NEXUS 4 AND NEXUS 10
Android 4.2 also add multiple user support on tablets for easier sharing — each user gets their own apps and data. It's cleverly done: if one user has already downloaded an app, the other users don't have to redownload anything to install it. Google showed us Bad Piggies running on one user account with saved levels and scores; when the other user installed the app, it appeared instantly in a completely fresh state. Apps are backgrounded when you switch away from an account — they can complete certain tasks like downloads but are otherwise mostly shut down. You can't have a music player running in the background from one account while using another account, for example. Overall, it's a well thought-out solution to the problem of sharing a single tablet with multiple people.
Other notable improvement in 4.2 include a "Daydream" mode that's essentially a screensaver, the ability to take actions directly from expanded notifications, and a number of accessibility improvements, including the ability to zoom in on any part of the screen. Widgets are now supported on the lockscreen, and you can swipe directly into the camera, which is a huge improvement. And Gmail's been added as a data source for Google Now, which has a number of new cards.
Here's the full list of new features:
  • Photo Sphere panorama photos
  • Gesture typing on the keyboard
  • Lockscreen improvements, including widget support and the ability to swipe directly to camera
  • Expandable notifications with that let you take actions directly
  • Message zooming in Gmail with the ability to reflow text automatically
  • Daydream screensavers
  • Accessibility improvements: triple-tap to magnify the entire screen, pan and zoom with two fingers. Speech output and Gesture Mode navigation for blind users.
  • Miracast support for wireless display sharing
  • Google Now can use Gmail as a data source for new cards, including improved flight tracker, hotel and restaurant reservations, movie and music recommendations. Photo Spot card recommends interesting places to take photos based on your location.
Android 4.2 will obviously ship with the Nexus 4 and 10, and we're assuming other Nexus devices like the Galaxy Nexus and Nexus 7 will receive the update in the next few weeks as well. Take a look at our exclusive feature to see how Android 4.2 was built.