Random Musings on the O Developer Preview 2
Each time Google releases a new developer preview, I rummage through
the API differences report
and the high-level overviews,
to see if there are things that warrant more attention from
developers, with an emphasis on mainstream features that any developer
might reasonably use. I also tend to emphasize things that may not
get quite as much attention, because they are buried in the JavaDocs.
So, here are my notes on O Developer Preview 2 (ODP2).
What Did I Say Last Time That Is No Longer a Concern?
Two months ago, I published my random musings on ODP1.
Of note, my concerns about multi-display testing were somewhat abated by realizing that
the simulated secondary displays handled it well.
Otherwise, what I had in that original post is mostly still relevant.
What���s Interesting in the Release Notes
Each developer preview has its section of the release notes.
In the case of ODP2:
The biggest concern is ���Even for apps not targeting O, users can use the Settings screen to enable background execution limits.���
This implies that all developers need to concern themselves with the
changes in Service behavior, the semi-ban on implicit broadcasts, and the changes
in background location behavior. Previously, this was limited to developers who
jumped to targetSdkVersion of O or higher. However,
I cannot find where in Settings that the user can make this change.
I cannot even find it in Developer Options.
So, it is unclear how much of an issue this is.
The release notes state that ���Developers using FCM/GCM with Android O should update their Google Play services SDK to version ��� 10.2.1, which is available from the SDK manager in Android Studio.���
That is curious, as IIRC, this raises the minSdkVersion to 14, meaning that it
is even firmer official Google policy to leave Android 2.x devices in the dust.
This is in the ���Known Issues��� portion of the release notes, so it may be that this
is a temporary requirement.
The remaining findViewById() implementations (Activity, Dialog, etc.)
have now been updated to return T rather than View, for consistency.
ODP1���s startServiceInForeground() on NotificationManager has been moved
to startForegroundService() on Context, which is a nice simplification.
As was discussed at Google I|O, there are new APIs for downloading fonts on
the fly from a font provider.
What���s Interesting in the ���Features and APIs��� Page?
For some reason, there are changes to Android that show up on the
���Android O Features and APIs��� page but are not mentioned in the release
notes.
Of note:
JobScheduler has a new set of behaviors.
A JobService can now have a work queue, with an eye towards replacing
IntentService. And you can attach a ClipData object to a JobInfo,
to be able to not only pass a Uri with the job, but to pass along any
permissions you have for the content identified by the Uri (e.g., a
Uri that you received from ACTION_GET_CONTENT or ACTION_OPEN_DOCUMENT).
Also, you have new limits that you can place on jobs via JobInfo.Builder,
including setRequiresBatteryNotLow() and setRequiresStorageNotLow().
VolumeShaper, rather than being a tool for managing 1980���s ���big hair���,
is an option for performing fade-in/fade-out/cross-fade sorts of audio
transitions.
What���s Interesting in the API Diffs Report?
Where most of the ���under the covers��� stuff shows up is in seeing the diffs
between the ODP1 and ODP2 APIs. There are more changes here than I would have
expected.
Of note:
ActivityManager getRunningServices() is deprecated, and it will return
only an app���s own services. This is part of the continued crackdown on apps
knowing what other apps are doing.
Your ServiceConnection implementations will now need to add an
onBindingDied() method. This will be called if the binding is permanently dead,
requiring a fresh bindService() call. Now, onServiceDisconnected()
represents a temporary suspension of the connection, but you may get called
with onServiceConnected() again later on, when the service starts back up.
AFAIK, this represents a change in onServiceDisconnected() behavior.
PendingIntent now has a getForegroundService() method. This works
like getService(), but apparently it will use startForegroundService()
instead of startService().
The Activity and Fragment onMultiWindowModeChanged() and onPictureInPictureModeChanged()
methods now take a Configuration object as a parameter.
The multi-display APIs now offer an onMovedToDisplay() method on Activity,
to find out when it is moved to some other display.
Fragment now has getLayoutInflater(), saving you from having to get
one from the hosting Activity.
The autofill classes and methods switched from a capital F (AutoFill...)
to a lowercase f (Autofill...). I eagerly await ODP3, where the lowercase
f will be replaced by some other Unicode glyph that happens to resemble an f.
Beyond the ���f���-ing changes, autofill has had other overhauls in its API.
Apps can now provide hints as to the roles of views, and there are a bunch of
new classes (FilLContext, FillEventHistory, SaveInfo, etc.). I suspect
that my sample apps will need a significant overhaul.
Bundle now offers to store UUID values, though
I argue that this should be in BaseBundle
There is a new suite of classes for IPsec, starting with IpSecManager.
Chronometer now offers isTheFinalCountDown(), possibly in homage to
a GEICO commercial.
What���s Interesting When You Try to Use ODP2?
The current release build of Android Studio (2.3.2) does not support ODP2,
despite the fact that it had supported ODP1, and despite the fact that the current
release build of Android Studio has supported then-current developer previews
in the past. I find it curious that Google thinks so little about release builds
of their IDE. Your code will still build and run just fine with Android Studio 2.3.2, but you
will get lots of unrecognized symbol errors in the Java editor, along with
related limitations (e.g., code completion).
