Today, with the official release of the Nexus 4, Nexus 10, and Nexus 7 HSPA+, Google has released the Android 4.2 SDK, "a new and improved Jelly Bean."

Along with the SDK release, Google has made available SDK Tools r21, the Android NDK, and of course some helpful API documents. Highlighting some of the benefits of the new SDK (and, by extension, Android 4.2), Google touts "Renderscript computation directly in the GPU" for the Nexus 10, "a first for any mobile computation platform," lock screen widgets, Daydream, incredibly enhanced support for external displays, and optimizations for international users.

A full list of changes (specifically those pertinent to developers) can be found in the API docs, linked at the end of this post.

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If you're a developer who's been waiting for the new development kit to drop to create some awesome 4.2 Jelly Bean-friendly apps, now's your chance. It's worth noting that the SDK Tools r21 package hasn't been listed yet on the Android tools download page, but you should be able to grab it as an update in Eclipse.

Source: Android Developers (Introducing 4.2, SDK Download, NDK, API Docs)

Liam Spradlin
Liam loves Android, design, user experience, and travel. He doesn't love ill-proportioned letter forms, advertisements made entirely of stock photography, and writing biographical snippets.

  • http://kennydude.me/ Joe Simpson

    Multi-Screen looks good :)

    • http://codytoombs.wordpress.com/ Cody Toombs

      I was thinking the same thing when I saw that in the list. Is it me, or was this not mentioned anywhere before today? I thought I'd already seen a list of the major new features, but I definitely hadn't seen that.

      It's clear from the feature description that this will make it possible to specifically target multiple displays. I really want to see this kind of thing running in a car someday. I see so much potential in this.

      • http://AndroidPolice.com/ Liam Spradlin

        You're not alone - I hadn't seen that gem mentioned anywhere before today.

  • Marc

    Got it!

  • pihlen

    I like that they rewritten the Bluetooth stack.

  • coversnails

    Why wasn't this released before 4.2 dropped so that developers could be ahead of the ball and have apps optimized before 4.2 hit the shelves?

    • pihlen

      I don't think it matters that much since the uptake if 4.2 is going to be quite slow. Developers are now starting to focus on 4.0

    • http://codytoombs.wordpress.com/ Cody Toombs

      That's kind of an unfair criticism...kind of...

      You've got to consider, Google has some secrets they'd like to keep until the last minute, otherwise the releases don't make nearly as much news or get the same level of excitement. It's hard to keep secrets while also giving out fully functioning SDKs and emulators to test new features with. They could always go the route of NDA's (non-disclosure agreements) and distribute to just a select few developers, but that never really works well and it causes competing developers to get very angry (for example, there's a guy who makes an alternative keyboard who is currently very pissed off and blames a LOT of stuff on Google because he sees favoritism in other forms).

      There's also the issue of which devices you're talking about. While the Nexus line is definitely becoming more mainstream (seriously, the N4 didn't last 60 minutes in ANY country), the fact is that it's still loosely intended to be a developer device. Ideally, and I hope to see this happen one day soon, people could activate their Nexus device to get actual developer builds of the software so they can do real testing while regular people can still get the timely updates and benefits of a pure vanilla Android experience. Unfortunately, that solution doesn't exist yet and regular people want to get the updates as quickly as developers.

      The economics don't make it reasonable to sell a true developer-only device (there's a whole discussion in just that subject), everybody wants updates and new features at a lightning pace, and the logistics make it challenging to get this stuff to developers in a testable status before hand. Even if Google offered hardware and software to developers with apps in the play store, so they got a first bid, it would still turn into a circus.

      • pihlen

        Which keyboard developer are you referring to?

        • http://codytoombs.wordpress.com/ Cody Toombs

          I'd rather not say, he and I already don't get along very well. There's no point in dragging names through the mud over some simple opinions.

      • coversnails

        Thanks for the answer, I wasn't trying to criticise the decision, just wanted to know why. I guess I just remember the sdk for ICS coming out before the Galaxy Nexus was released, but I suppose that had more to do with the GB to ICS jump being muxh greater. I've only so far noticed MX Player not being compatible with 4.2 which triggered the question.

        • http://codytoombs.wordpress.com/ Cody Toombs

          Sorry, I see comments similar to yours with every major release of Android and they are usually meant harshly. It is a good question and one I'd like to see Google try to answer directly. I think Google takes a lot of flak over this when they really are handling it fairly well.

          I've seen how some other companies do major updates like this. Apple releases developer builds that are barely working, meaning many developers have to invest in extra devices to do their testing for upcoming versions rather than commit their daily driver.. Blackberry has been good very recently with loaner devices, but their updates are very slow to release and missing many core components that developers need for testing. Then there's Microsoft...don't...get...me...started... They cost me 5 months of work. #rage_face.

          Ironically, Google can't really win. They can keep new versions limited to developers for a while, causing customers to whine that they can't get the newest toy. They can release it to a select few devices (like they are now) and both developers and enthusiast customers are happy, but this will always be criticized for causing 'fragmentation' and slow rollouts so regular customers are constantly stuck on older versions. Or, they could even push other OEMs to do faster updates, leading to a ton of market apps being buggy and angering customers for not having a way to make sure apps work on the new version on day one. It's like being the DMV, everybody needs your product but they will always find a way to complain about how it's done :)

  • marcusmaximus04

    Didn't see it in the NDK changelog, so I'm curious: Could you guys poke through the Nexus 10 and see if there's a lib file for OpenGL ES 3.0? In theory, it should be under /system/lib and be named something along the lines of "libGLESv3.so".

    I ask because the Nexus 1 was released with the ES 2.0 lib there, even though it wasn't added to the API until a couple months later. I was able to link against it and deploy ES 2.0 code before the actual API's were added.

  • Davy Jones

    Looks like there is now support for MMS group messaging. From the menu in the messaging app:
    "Group messaging: Use MMS to send a single message when there are multiple recipients"

  • mark

    Just got 4.2 for my nexus 7 wifi

  • firethorn

    Hm, from a dev's reply I understand that the API to enable and disable the GSM/CDMA radio was removed, and hence apps can no longer toggle flight mode. This annoys me a bit because I liked having flight mode automatically set during the night.