Android is really turning into a jack of all trades, having become the OS of choice for phones, tablets, face computers, and now wristwatches. The combination of flexibility, open source code, and low cost of entry make it a prime candidate for countless utilitarian purposes. With the upcoming release of Android L, Google is aiming to make it even easier to deploy highly specialized environments with a new feature called Task Locking that allows a single app to take control of the interface and prevent users from switching apps or even seeing notifications.
You saw Android Wear a couple of months ago when Google unveiled the SDK and both LG and Motorola presented the first promotional pictures. Then you watched the Google I/O keynote that officially launched the LG G Watch and Samsung's surprise addition of the Gear Live. And now you've got a shiny, brand new Android Wear watch before you... but all you can think about is ripping into the digital guts of that thing and doing all of the awful things that Google never intended.
Back in KitKat, we were introduced to translucent system bars, which gave app developers the ability to make the navigation and status bars semi-transparent. Reclaiming as much of the screen as possible became an obsession for many fans as they demanded their favorite apps go "full bleed." With Android L, Google is treating us to even more flexibility by allowing developers to set their own color for the status bar, or even turning it completely transparent.
A couple of days ago, AOSP was graced with a series of freshly created "l-preview" branches and a massive push of brand new code. As we know now, quite a bit of that code push wasn't truly representative of the L developer preview. (Very sneaky, Google.) Most of the truly new updates belonged to GPL-licensed projects, which Google is obligated to release in a timely fashion. The remaining projects with "l-preview" branches were filled with a recent snapshot from the Master branch.
It looks like all of the recent Nexus devices are covered - everything from the 2012 Nexus 7 up through to the Nexus 5. Of course, just because branches have been published for these devices, it is not absolute confirmation that this entire list of devices will receive an official L release.
Battery life on Android has been a bit of a sore spot for many users, mostly because it's simply not good enough. Most devices can make it a day on moderate use, and a few can even do so comfortably, very few phones can hit two days without some time on the charger. The Android "L" release is making several improvements to power efficiency via Project Volta, but there are also ways to improve 3rd-party apps, and that's where the new Job Scheduler comes in.
If it's not already completely obvious, the L Developer Preview is shaping up to be an absolutely massive sea change for Android. While we've been treated to an entirely new design language called Material, a redesigned Recents screen, huge performance improvements, and over 5000 other new APIs and features for developers, it's easy to overlook plenty of exciting improvements that aren't quite as flashy. One such change was briefly mentioned by Dan Sandler during the "What's new in Android" session: Multi-Networking, the capability to maintain multiple network connections simultaneously.
Last year, at Google I/O 2013, some major new features and improvements were announced for Google Cloud Messaging (GCM) -the replacement for Cloud to Device Messaging (C2DM). A couple of the new bits were even featured during the keynote, particularly notification syncing, which the audience loved. The one thing most people don't know is that most of the coolest things announced that year were marked as beta and locked behind an application process.
If we're being honest, it's hard to deny that one of Android's most obnoxious flaws comes in the category of audio performance. Playing some music is generally fine, but the issues start to become obvious after introducing very high quality audio or trying to achieve precise timing or real-time processing. With the L Developer Preview, it appears that Google is driving to improve upon these weaknesses and give audio performance the shot of adrenaline it needs.
If you couldn't make it to Google I/O, and thus couldn't get one of the first Android TV units as part of the developer swag, you can still start developing your apps for the platform's retail debut later in 2014. Google has included Android TV modules in the official Android SDK, underneath the Android L (API 20) package. That includes an emulator specifically for TV, so you should be able to build and test apps without any extra hardware.