July 18, 2024
Android Automotive OS Improvement on Mac – Grape Up

Much like how they did for the exploding smartphone market over ten years in the past, personalized infotainment working programs and open-source software program seem like sweeping the automobile trade. The Android Automotive OS has been making headway in lots of market niches, beginning with full-electric automobiles like Polestar a couple of years in the past. It’s solely a matter of time till the group and ecosystem mature sufficient to turn out to be a severe drive for enabling cellular improvement on one more entrance: the vehicles.

Whereas Android Auto (a reputation simply confused with the subject I shall be going over right now) and Apple CarPlay have had a long-standing within the area, they got here with a number of caveats and restrictions. These largely pertain to the truth that many features-to-be would depend on low-level entry to the {hardware} of the automobile itself. This proved to be tough, with each options providing a restricted set of human-machine interplay capabilities, akin to a heads-up show (the place obtainable) and radio. With that in thoughts, the use case for offering apps for the precise OS operating the automobile was clearly wanted.

The group and documentation are nonetheless of their infancy and don’t but present a deep dive into Android Automotive OS. Furthermore, the training curve stays steep, however it’s undoubtedly attainable to piece collectively bits of data associated to improvement and deployment. On this article, I try and do exactly that, all whereas emphasizing the MacOS aspect of issues.


As a normal precept, Android improvement can both be performed on an actual gadget or a corresponding emulator. Given the delicate nature of granting purposes entry to the precise automobile {hardware}, the app has to go the entire 9 yards with Google Play Retailer eligibility. On prime of that, it has to adapt to certainly one of a number of classes, e.g. a media app to be allowed within the AAOS system. The excellent news is that there’s a risk for an app to combine and match classes.

Thus, distributors supporting the brand new ecosystem (as of now, amongst others, Volvo and Polestar) opted for making a customized automotive gadget emulator that carefully matches the specs of the infotainment programs contained inside their vehicles. Regrettably, Polestar and Volvo emulators include proprietary code, are based mostly on older Android releases, and don’t but help the ARM structure, which is of particular curiosity to builders working with ARM-based Macs.

Whereas official AAOS emulators can be found in Preview releases of Android Studio (from the Electrical Eel model onwards), typically the duty at hand requires personalized {hardware} and parameters. On this case, a customized Android model would must be constructed from supply.

Constructing from supply

Constructing from supply code is a time-consuming enterprise that’s not formally supported outdoors 64-bit Linux platforms (whatever the goal structure). With that in thoughts, selecting a devoted AWS EC2 occasion or a naked steel server for constructing the ARM variations of the emulator appears to be one of the best general answer for Mac builders.

A requirement for unofficial builds on Mac gadgets appears to be having a disk partition with a case-sensitive file system and in any other case following some further steps. I selected a devoted construct system as a result of, for my part, it wasn’t definitely worth the hassle to arrange an extra partition (for which I didn’t actually have the disk capability).

The selection of the bottom Android launch is basically depending on the goal gadget help, nevertheless, for ease of improvement, I’d advocate selecting a current one, e.g., 12.1 (aka 12L or Sv2). Mileage could range with reference to really supported variations, as distributors have a tendency to make use of older and extra steady releases.

After getting their arms on a improvement machine, one ought to prepare the build environment and observe instructions for building an AVD for Android Auto. The overall workflow for constructing ought to embrace:

  1. downloading the source code – this will likely take as much as an hour or two, even with first rate connection and department filtering,
  2. making use of required modifications to the supply, e.g., altering the default VHAL values or XML configuration,
  3. operating the construct – once more, could take as much as a number of hours; the extra threads and reminiscence obtainable, the higher,
  4. packing up the artifacts,
  5. downloading the AVD package deal.

Leaving out the utilization specifics of the lunch and repo for now, let’s check out how we are able to make the default AAOS distribution match our wants somewhat higher.

Tailoring a tool

VHAL (Car {Hardware} Abstraction Layer) is an interface that defines the properties for OEMs to ultimately implement. These properties could, for instance, embrace telemetry information or maybe some data that might be used to establish a selected automobile.

On this instance, we’re going so as to add a customized VIN entry to the VHAL. This may allow app builders to learn VIN info from a supposed automobile platform.

First off, let’s begin with downloading the precise supply code. As talked about above, Android 12.1 (Sv2) is the discharge we’re going to go together with. It helps model 32 of the API, which is greater than sufficient to get us began.

So as to get sources, run the next command, having put in the source control tools:

<p>> repo init -u https://android.googlesource.com/platform/manifest -b android-12.1.0_r27 --partial-clone --clone-filter=blob:restrict=10M</p>

<p>> repo sync -c -j16</p>

Partial clone functionality and selection of a single department make it possible for the obtain takes as little time as attainable.

After downloading the supply, find the DefaultConfig.h file and add the next entry to kVehicleProperties:

.config =
             	.prop = toInt(VehicleProperty::INFO_VIN),
             	.entry = VehiclePropertyAccess::READ,
             	.changeMode = VehiclePropertyChangeMode::STATIC,
 .initialValue = .stringValue = "1GCARVIN123456789",

An summary of HAL properties could be discovered within the reference documentation.


Having modified the default HAL implementation, we’re now free to run the construct for an ARM goal. Run the next directions contained in the AAOS supply listing – utilizing a display screen is very really helpful if connecting by means of SSH:

display screen                         
. construct/envsetup.sh

lunch sdk_car_arm64-userdebug

m -j16      	                # construct the requisite partitions

m emu_img_zip                   # pack emulator artifacts right into a downloadable .zip

Be aware the sdk_car_arm64-userdebug goal wanted for emulation on ARM-powered Macs. A car_arm64-userdebug variant additionally exists. Be certain that to not confuse the 2 – solely the previous has emulation capabilities! Strive operating lunch with out parameters to see a full record of targets.

The -jXX parameter specifies the variety of threads to make use of whereas constructing the Android. If the thread depend will not be offered, the construct system will try to optimize the variety of threads robotically. Persistence is suggested, as even with first rate {hardware} assets, the compilation is sure to take some time.

The ensuing emulator artifact ought to be obtainable within the out/ listing underneath sdk-repo-linux-system-images.[suffix].zip to be downloaded by way of scp or your file switch shopper of alternative.

Working a customized emulator in Android Studio

Now that now we have our bespoke emulator picture constructed, there’s somewhat trick concerned in making it obtainable for native improvement with out creating an entire distribution channel, as outlined within the handbook.

First, find the ~/Library/Android/sdk/system-images/android-32 folder and unzip your emulator archive there. The listing could be given an arbitrary title, however the general construction ought to observe this structure:

|_ [your name]
   |_ arm64-v8a
E.g., ~/Library/Android/sdk/system-images/android-32/custom_aaos/arm64-v8a.

Second, obtain the instance hooked up package deal.xml file and regulate the gadget title to suit your wants. A package deal.xml is added after downloading and unpacking the emulator sources from the Web and must be recreated when unzipping domestically. After restarting the Android Studio, Gadget Supervisor ought to have an choice to use your brand new ARM image with an Automotive AVD of your alternative.

After efficiently operating the emulator, a newly created VIN property ought to be seen within the Vhal Properties of Automobile Knowledge. Good one!

Whereas studying VHAL property values is out of the scope of this text, it ought to be simple sufficient with a few Automobile library calls, and Google created an example app that does the very factor.

Downloading the above instance (CarGearViewerKotlin) is extremely really helpful – for those who’re capable of construct and run the app on the emulator, you’re all set!

Facilitating AAOS improvement on M1

One of many issues I stumbled upon in the course of the improvement setting setup was that the Automobile library was not being detected by Android Studio, whereas the app nonetheless builds usually from CLI. This seems to be a recognized concern, with no official patch but launched (as of October 2022). Nevertheless, a easy workaround to incorporate a .jar of the Android Automotive library seems to work.

In case of operating into any issues, import the library from ~/Library/Android/sdk/platforms/android-32/elective/android.automobile.jar by copying it into libs/ listing within the undertaking root and add the next directive to your most important construct.gradle file, if not current:

	implementation fileTree(embrace: ['*.jar'], dir: 'libs')

As soon as the undertaking is re-imported into the IDE, Android Studio ought to be capable of choose up the Android Automobile library for import and autocomplete ideas.

The Actual Deal

Emulators are ample for testing functions, however what about actual gadgets, akin to branded infotainment facilities? As talked about earlier than, no less than two main distributors (Volvo and Polestar) provide the built-in Android Automotive expertise out-of-the-box of their automobiles. System photos and implementation particulars, nevertheless, are proprietary and require enrollment into their respective developer partnership applications. Polestar provides a free AVD that emulates Polestar 2 conduct, together with the display screen dimension, body and {hardware} controls – alas, at present solely obtainable for x86-64 platforms.

One of many alternate options value contemplating is the set up of Android Automotive on an actual gadget – be it a pill or perhaps a Raspberry Pi platform. Some modules will nonetheless require virtualization, however switching to a bodily gadget might be a serious step within the path of higher {hardware} compatibility.

All of the above considerations elevate the query – the way to get the app to work on an actual AAOS inside a automobile? I haven’t discovered a conclusive reply to that query, no less than one which gained’t contain third events holding the precise documentation assets for his or her gadgets. It is smart that some doorways will keep closed to the final programming viewers because of the safety implications of making apps for vehicles. Nobody, in spite of everything, would need their automobile to be taken management of by a rogue social gathering, would they?

Ultimate ideas

Programming for Android Automotive remains to be an adventurous endeavor. Although the system has been round since 2017 (with APIs open to public in mid-2019), official documentation can nonetheless really feel considerably inaccessible to newcomers, and the developer group remains to be in its budding section. This requires one to piece collectively varied bits of official guides and normal Stack Overflow data.

Backside line: AAOS remains to be behind the diploma of engagement that the common Android working system has been having fun with up to now. The longer term is trying vivid, nevertheless, with distributors akin to GM, Honda, BMW, and Ford keen to leap on the automotive improvement bandwagon in years to return. If that’s the case, the ecosystem will inevitably develop – and so will the group and the help it gives.