Develop Reference

Is it possible to build Android Automotive apps using common UI layouts like those for mobile phones?

I'm talking about the usual ConstraintLayout or LinearLayout from Android development for mobile phones. Is it possible or allowed to create and install an app built like this on the Android Automotive OS (not Android Auto)?
If the answer is yes, do you have any documentation regarding this or project examples/samples?
Publishing the app on the Automotive Store is not important for me, Google wouldn't allow this anyway. I just want to be able to create a very custom app for me or a possible OEM.
I know there's an Android for Cars Library but it's not even working for AAOS at this moment, only for Android Auto.

Yes, you can create and install normal Android apps that use common layouts on the AAOS Emulator. You may not be able to upload these apps on the store but an OEM probably can install any apps it wants.
Check the 'A Better Routeplanner' app, it was uploaded by Polestar on the AAOS store and it probably uses the UI layouts you mentioned considering how custom and similar it is to the mobile version.
https://play.google.com/store/apps/details?id=com.polestar.abrp.production.android

It depends on the user specific case, i.e. Is it going to be using navigation or radio for example.

Modify the android source code so that it allows only those applications to be installed which are developed by me

I am working with a client on one of their ideas. The idea requires the android source code to be modified in such a way that it only runs applications which are developed by us and blocks applications from all other developers. Is it possible to do this?
Only applications which we develop for our custom android build will be installed and applications from play store or other developers won't be installed. Can anyone please guide me on this?
Thanks in advance!

Certainly possible... just modify the system to only start applications signed by your identity. You'll need your public key baked into the framework.

I'd like some direction about developing a multi-platform mobile-app

There are so many tools out there for mobile development that it's information overload. I'm a programmer as well and would like some opinions on what would work best for my requirements. I don't own a mac and have no plans on purchasing one if i can help it. The app i'm trying to build seems relatively simple. I also want to have IPhone and Android versions of it, with possibility for Windows phone in the future.
needs to be a free version with youtube videos - so access to the youtube player
i'd like to be able to embed some articles - not sure about this one, either just text or pdf etc.
needs to have the option to upgrade to a paid version.
the paid version would be a subscription based service.
the paid version would be serving video content from S3(or other better sources)
the paid version needs to have a notification/push service where i can push content to the app on a monthly basis.
So, given all these, i've looked at appcelerator, phonegap, xamarin and lots of other services. They all seem good but given the requirements, i'm starting to lean a little bit towards phonegap as this is not going to be a game and it's a service primarily and it can handle both Iphone and Android as well.
Thanks for your input.

I think PhoneGap is your best bet, I've spoken to quite a few Mobile Application Development Company's around my area and they all speak highly of it. Phonegap has recently came into the possession of Adobe so you can expect it to become a more highly supported/documented platform that you can create multi-platform apps from. Plus it meets your requirements
I'm avoiding PhoneGap myself at the minute because I want to get to grips with Obj-C and C# to expand my knowledge of different programming languages but if I was trying to target as many platforms as possible, PhoneGap is top.

App deployment with Cultured Data for mobile apps

We are developing some mobile apps for iOs and Android platforms. And our target markets are different countries. At the moment we create an app for every each market (same app with new cultured data). This creates lots of provisioning profiles, apps , manageability issues...etc
I wonder what is the best practise for this case.
Many thanks.

check these for help on internationalization and localization
http://developer.apple.com/internationalization/
http://www.icanlocalize.com/site/tutorials/iphone-applications-localization-guide/

Best platform for programming to IPad and new Windows and Android Pads

would like to build an app that can run on any of the new PAD's hitting market.
I don't want to limit our users to a specific OS.
What is the best solution to allow all these pads to use our app.
The app needs to be able to run offline.
Thanks!

You could write a web application and use HTML5 for off-line caching.
http://diveintohtml5.ep.io/offline.html
Alternatively, you could try and use Titanium Mobile.
http://www.appcelerator.com/products/titanium-mobile-application-development/

You should also spend some time reading this discussions:
is-there-a-multiplatform-framework-for-developing-iphone-android-applications
technology-to-write-iphone-blackberry-and-android-phone-at-the-same-time

Have a look a MonoTouch, it will let you write all your logic in C# over all the main mobile platforms. However you still need custom UI code for each platform, but as least it will all be in C#.
(Better then having to use C#, Java and Objective C)

You could use Adobe Air that could works in most of Mobile/Tablet operating system Iphone,Android and Windows 7. but im not sure if Apple will approve your App if you plan to released to the App market.
Another way to think about it is to create an HTML resources and then integrated in away seems native to the system its more work but you will have a higher chance to get approved from apple and the app look more integrated with the OS .

The obvious -- and currently free -- answer is to use Adobe FlashBuilder to develop iOS apps. There is an iPhone and iPad emulator included. This does not use xcode, but you get most of the features to work with, and you can also develop Android apps from the same set of code. Further, with minor modifications for mouse usage, you can also have the apps run on any desktop as an Air app.
Adobe's website has detailed directions for how to create iOS apps on Windows with Adobe Air, though the most useful instructions for Air are from untoldentertainment.com.