The LG G Watch and Samsung Gear Live - both featuring rectangular screens - mark an attempt to standardise the way Android wearable devices function. Google said that Motorola's circular Moto 360 would not
be released until "later this summer".
Analysts say the move to a unified approach could drive sales he problem with smartwatches so far has been that
the sector hasn't quite decided what it wants to be - is it a phone on your wrist or an accessory device," Steffen
Sorrell, from the Juniper Research consultancy, told the BBC.
"Once you introduce Android Wear, it will hopefully provide a more focused case for what the devices are capable of. And that's a direction that could invigorate the market." LG said the G Watch costs $229/£159 and would initially be made available to 12 countries including the US, UK, France, Germany and Japan. It is due to ship on 4 July. Samsung said the Gear Live would cost $199/£169 and ship on 7 July. Both will require the owner to have a phone running Android 4.3 or above. Vibrating notifications Google dedicated an early part of its I/O developer
conference presentation in San Francisco to its new wearable OS .David Singleton, director of engineering in the firm's Android division, said one of its core aims was to be able to "quickly show you relevant information, and make sure you never miss an important message, while letting you stay engaged with the people that you are actually with" To achieve this, when notifications are received by the
user's smartphone they can be set to make the watch
vibrate on the user's wrist.
If the owner then dismisses the alert and carries out a
follow-up action on the watch, such as scheduling an
appointment, the details are "immediately synched
across" so that the smartphone also hides the
notification and adds the meeting to its diary.
Users can also reject calls to their phone via the watch
and select a pre-set text message to explain why, and
bring up map navigation.
Voice commands
Much of Android Wear's user interface (UI) relies on the
firm's Google Now card-based system. It allows owners
to swipe up and down to different types of information,
and left and right to find out more about a specific topic.
However, Mr Singleton's demonstrations at the event
suggested that his firm expects consumers to carry out
many of the watch controls by voice command.
Saying "OK Google" prepares the device to take an
instruction - similar to the way its Glass eyewear
functions.
Android Wear can be used to reject phone calls, track
fitness, accept voice commands, estimate journey times,
schedule appointments and store travel plans
Example tasks shown on stage included setting
reminders, taking notes, setting an alarm and playing
music.
Mr Singleton also highlighted that many of the OS's
functions would be triggered by "context", without
requiring a human action.
He showed how flight information could be flagged on
the day of travel, a restaurant reservation close to the
time of the booking, and local bus timetables when
travelling abroad.
He added that this functionality was also being made
available to third-party developers, giving the example
of a place being highlighted when the owner approached
if it had been "pinned" by a friend on the Pinterest social
network.
Mr Singleton showed off Eat 24, an app that can be used
to order sushi and pizza
Other examples of third-party software included an app
that makes it possible to order fast food, and one that
allows owners to hail a taxi - both designed to involve
few button presses.
The watch does not have access to a special store to
download such apps, but instead automatically gets
them when the handset version is downloaded to a
paired phone.
Analysis: Richard Taylor, North America technology
correspondent
Android Wear presents an opportunity for Google to
become the provider of the "go-to" platform for
smartwatches, stealing a march on Apple.
Until now, smartwatches have not been terribly "smart",
in part because of a lack of decent apps.
Making the mobile version of Android easily tweakable
by developers to run on your wrist should deliver a huge
variety, especially if they can bring a deep integration
with your handset.
But much will depend on execution; and for many use-
cases, the case has yet to be made for a 2in (5cm)
screen to effectively replace the 5in one in your jeans
pocket.
The smartwatch sector has still to prove it will have
mass appeal
'De facto standard'
One industry watcher who has tested a prototype
Android Wear device said he expected it to now become
the de facto standard for wearable kit with screens.
"What Google is trying to achieve here is a glanceable UI
and that's the key to wearables," said Ben Wood, from
the CCS Insight tech consultancy.
Google focused on voice commands, but third-party
developers are creating keyboards for Android Wear
"Android Wear is not a full operating system, it's merely
a smartphone companion, and my view is that's the right
starting point for Google at a time when everyone is
feeling their way in the dark and trying to find a
compelling case for what to do with it beyond the basic
stuff.
"I think all the other proprietary efforts with [Samsung's
use of] Tizen and other proprietary software will now be
pushed to one side because of the public awareness
Android Wear will generate, how it will become the focus
for developers and the fact that people will have the
guarantee that they can use one brand of Android Wear
watch with another brand of phone."
He added, however, that the voice commands might
prove problematic in crowded, noisy environments,
noting that third-party developers including Minuum
were already working on Android Wear keyboards to
address the issue.