Android has had the same basic aesthetic since Ice Cream Sandwich debuted two and a half years ago. Sure, the colors and layouts have changed a bit, but Holo has been alive and well all this time. KitKat showed the first break from that design when it was announced last year, but Android L is going to be the start of a new era for Android.
This is the biggest update to the platform since at least 2.0, but the more I see of Android L, the more I think this could be the biggest thing to ever happen to Android. As an Android user there are a few things you need to know about L, so let's dig in.
Android is about to get pretty
The design of Android 4.4 was fine, but take the Google Now Launcher out of the equation, and it was very much the same as Jelly Bean with a few color tweaks. Android L (we don't have a name or version number yet) has officially ditched Holo as the interface design language in favor of Material Design.
The best way to think about Material Design is that it's about layering UI elements while still keeping the design flat and "natively digital." The new Android SDK will allow developers to set an elevation value for different UI elements and have the OS render subtle shadows on the edges to make it look like some parts of an app are floating just above others. The new post button in the updated Google+ app is an example of this technique.
Google is also doing an about-face on the subject of colors in Android. Material Design on Android L will stress bright colors and eye-catching design. The revamped Calculator and Dialer apps were included in the developer preview of L as an example of what's to come, and they really stand out. It is going to be a little jarring with apps using so many reds, blues, greens, and even some pink. It doesn't makes a lot of sense until you begin to explore Material Design apps and see how the use of bold colors can make even basic apps feel interesting in a way Holo never could.
The key to Android L's new look and feel will be the way Material Design handles animations. Throughout the system UI, the use of animations for touch interaction is so much more immediate than in older versions. Nothing simply refreshes in a changed state with Material Design -- even buttons and checkboxes have animations attached to them when they are tapped. Some of this feels a bit like Android's design head Matias Duarte is reaching back to his Palm days to bring some webOS flair to Android.
Notifications will never be the same again
Google added a way to access notifications from the lock screen way back in Android 4.0, but things are changing in Android L. When this update hits devices, the notification shade and lock screen will become one in the same. Even if you have a pattern lock, notifications will be listed in both places, allowing you to launch them while the device is locked. Of course, you'll be asked for your PIN or pattern before you can see any of the content, but it's much more convenient.
When you clear a notification from either location, it disappears in the other. Why? They're basically the same thing. As such, opening a notification is the same as unlocking the phone. This approach is much more useful than the old implementation because you lost all notification access on the lock screen when using and kind of security.
The look of notifications has been overhauled too. The notification shade is no longer a solid block the covers everything behind it. The notification cards slide down over top of a shaded backdrop with a status bar up above. If you drag down again, you'll get the new Quick Settings panel. Google has finally listened to reason and made these buttons behave correctly. Tapping on them actually toggles the corresponding settings, and pressing on the labels launches the settings menu.
Notifications are finally creeping out of their traditional location with so-called "heads-up" notifications.
There is one more type of notification coming in Android L, and it might make the experience radically different. Notifications are finally creeping out of their traditional location as so-called "heads-up" notifications. When something important happens, you'll get a banner across the top of the screen that includes the usual action buttons, but you can also ignore it or swipe it away immediately. This is probably the biggest change to Android notifications since we gained the ability to swipe them away in Ice Cream Sandwich.
A new runtime means more speed
Android 4.4 brought with it a new developer option to try an updated application runtime called ART. We were told at the time this was to be the eventual replacement for Davlik, which is what we've had since Android was born. The last significant update to Dalvik was way back in Android 2.2 Froyo, and now it's making way for ART as the default in Android L. But what the heck does it do, anyway?
Dalvik and ART are Java virtual machines -- they take the Java code that developers use to create applications and turn it into native code that can be run. Dalvik's 2.2 Froyo update made it a Just-In-Time (JIT) compiler, which means it sorted out the Java as the application was run in real time. ART (which stands for Android RunTime) is an "ahead of time" compiler -- that is, it generates the native code when an app is installed and caches it. The result, in many cases, is improved performance.
Switching to ART on Android 4.4 caused lots of apps to crash, but this is less of a concern on Android L, even at this early stage. The Dalvik runtime has been completely purged from Android L, leaving ART as the sole runtime environment. So are apps going to be super crashy? Well, not as much as with ART on KitKat. The new version of ART is backward compatible with non-ART apps, so there shouldn't be any serious errors. The preview build does have some problems with a variety of apps, but it's not all ART's fault. That's just how alpha software is.
L multitasking fixes the oldest annoyance in Android
The multitasking button showed up in Android 3.0, emphasizing the more visual nature of Android app switching. However, the app-based approach to flipping between apps led to an odd quirk in the way Android apps connect to each other. Here's an example: you're on a webpage in Chrome and you click a link that opens the Play Store app, then hit the multitasking button. What do you see? On Android 4.4 and below, the app switcher has an entry for Chrome with an image of the Play Store page you were just on. This is because Chrome called up the Play Store, so the activity is still under Chrome from Android's perspective. It's mega-confusing.
In Android L, the multitasking interface is smart enough to know that apps should be separated in the card stack. So instead of seeing a Chrome listing with the Play Store UI, you'll get a Play Store card with a Chrome card behind it. This is activity-based multitasking, and it's only the start of what Android L will be able to do.
Apps under Android L will be able to generate multiple cards in the multitasking interface based on individual activities. The example shown off at I/O was Chrome spawning two different tabs in multitasking so you can jump between a different app and the tab you want in a single step. The interface for multitasking is also completely new -- it's a stack of cards that you scroll through vertically, a bit like tabs in Chrome. It's buttery smooth, and like a lot of other UI elements in Android L, it's just fun to play with.
Okay, Great. When do I get it?
What we have right now is the developer preview, which Google has never done before. There are a lot of API and interface changes this time, so Google clearly wanted to give devs a few months to get their apps in order. Android L is targeted for release this fall, probably with the release of a new Nexus tablet. However, there's no telling if this developer build will be updated along the way, or if this is the only taste of the unnamed treat we'll get before it's fully baked.
HTC is the only company that has made an official statement on L releases. It promised shortly after the keynote that it would get Android L out to devices starting 90 days after release. Of course, that just means the unlocked international and developer edition devices. If you got an M8 through a US carrier, the wait will be at least a month or two longer. Other manufacturers are staying silent on the matter, but I'd expect current flagships to be on a similar timetable.
Remember, this is only a developer preview right now. The details could change dramatically before the final version is ready. There's no point worrying over the layout or colors -- there's a lot of work still to be done. Whatever L ends up being, it's going to be a gigantic leap for Android.