Random Musings on the Android 12 Developer Preview 2April 10, 2021
Random Musings on the Android 12 Developer Preview 2
Each time Google releases a follow-on developer preview, I rummage through
the incremental API differences report,
the release notes,
and even the release blog post,
to see if there are things that warrant more attention from
developers. I try to emphasize things that mainstream developers might use but may not
get quite as much attention, because they are buried in the JavaDocs.
Just shy of a month after Developer Preview 1 was released, we got Developer Preview
What Amuses Me
Google has gotten into a bit of a habit of soft-releasing certain changes. They
include the changes in the SDK, but do not talk about them in the announcements
and documentation. Then, when the next developer preview comes around, they start
touting the “new” stuff… even when it had been in the SDK already. So, you may want
to start by reviewing my Developer Preview 1 musings,
as I mention some things there that only formally got announced today, including:
Hiding application overlay windows
Secure lockscreen notification actions
App digest API
Keeping companion apps awake
And, as a result, these random musings will be a mix of stuff that is “really real”
here in DP2 and a preview of stuff that might get announced in DP3 in a month or so.
What I Apparently Missed For Years
I never noticed the bandwidth estimation APIs
tucked away in the
NetworkCapabilities object. They have been around since Android 5.0;
Android 12 is improving them a fair bit, in terms of expected accuracy and relevance.
What May Cause Problems For You
If you use the accelerometer, gyroscope, or magnetic field sensors, you may need
to declare a permission to read those at high rates.
What Is Finally Getting Some Love
App widgets — which had been a moribund backwater for years — are getting
some updates. It’s almost as if competition matters or something.
But, we can
apparently use subclasses of
A bunch of new methods were added for configuring particular elements
setColorStateList()). We can request specific sizes
and control the maximum size for a resize operation.
And we can provide a description
and a layout to use instead of an image for the preview.
I thought app widgets might get replaced someday, but at least for now, Google
is trying to improve what we already have.
What Just Keeps Getting More and More Love
Notifications now have a
Despite the description, based on other options,
this appears to be designed for VOIP apps or other apps that might raise a notification
representing an incoming call.
What May Make a Splash in DP3
What Makes Me Wish I Knew More About Mobile Carriers
Apparently, 5G networks can be “sliced”.
Mobile carriers can “virtually divide their
networks in portions and use different portions for specific use cases; for example,
a corporation can have a deal/agreement with a carrier that all of its employees’
devices use data on a slice dedicated for enterprise use.” I am not well-versed in 5G,
but I am still surprised that I had not heard about this capability.
There is a new
to be able to “configure and manage Virtual Carrier Networks”. I am not an expert
in mobile networks, but this feels a bit like exposing Google Fi-like ability to
combine multiple networks into a seamless aggregate network.
What May Be Good or May Be Bad
There is a new
described as “allows an app to use exact alarm scheduling APIs to perform timing sensitive background work”.
I do not know if this means that the
exact family of
AlarmManager APIs will
now work better (good!) or if this means that you need a permission to be able
to use them even in their current state (less good!).
What Is Here Today, Gone Tomorrow
is deprecated. And the DP1
permissions were removed outright.
A version of
was added and deprecated… both in Android 12 DP2, if the docs are to be believed.
What Is Gone Today, Stumbling Around Like a Zombie Tomorrow
AnalogClock widget got new methods.
What Is Still Missing in Action
The app search APIs were revised
but were not yet announced.
What Else Seems Interesting
Apps can now persist a preferred night mode behavior.
There may be a new option to initialize the native heap with zeros,
which, if true, is a nice safety enhancement.
There are now
List forms of methods like
for being able to check a list of
Uri values at once.
We can now ask a
PendingIntent what it is used for,
There is now a new external storage directory for recordings.
We now have solid and patterned ripples.
Apps can control notification channel… fields?.
There is a new
that does… something with media metrics.
There are now an official system color palette.
We may be getting APIs for determining the status of individual batteries.
It’s unclear if this is for devices with multiple internal batteries or if
this is for some sort of external battery.
There may be new options for different types of app installs, such as
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