Adobe Flash Builder - actionscript-3

Question

Is there any way which can be adopted, to create cross platform responsive mobile apps using Flash Builder ?
We are using our custom written Resigning Engine for this purpose right now, but we tend to replace it with any generic Resigning tool or to cater responsiveness for all kind of devices/platforms.
Being on the same cross platform development, i.e. Flex, Action Script and MXML, is there any solution for this?
Thanks

Answer 1

It's possible deploy Flex-apps on Mobile devices, see Mobile app development
at Adobe Devnet more details

Answer 2

You definitely can develop Android and iOS apps using Adobe Air, Flex, AS3, MXML and publish them on Apple App Store and Google Play Store. But it's limited to these platforms, and Adobe is very unlikely to add any new platform to this list.
Pros:
it's really cross-platform. Once your application works on one, it's really easy to get it working on the other; so the development cost compared to native applications is much lower;
you may have some OS specific features/design; using by example OS specific CSS directives;
You perfectly may create an app with a responsive design, all tools are provided, but like for HTML/CSS, it requires a lot of work;
you may access all phone features (sensors, camera, etc...) using Adobe Native Extensions
Cons:
the size of the generated application: as it includes the AIR runtime, even a very simple app will weight around 12 Mb (9 for the runtime + 2.5 for Flex);
the performances are correct but not as good as those of native apps; one of the reasons is that Flex does not allow to use GPU for rendering (but Flex is not a framework for creating games);
it would be costly to get an app looking like a native one, as you would have to mimic all of native components. There was a project to do this (Eskimo), but it looks dead, and the components were not polished enough to be used in production when they stopped the development;
Adobe Native Extensions offer is rather limited, and they are quite tricky to write; (these drawbacks are not strong ones: you can write extensions, assuming you know to write native code; and most of the common features are available as ANE);
like with any other cross-platform technology, there are a few issues that you can't fix by yourself; you just can wait for Adobe to fix them when it's a problem in the compiler or the AIR runtime; hopefully they follow a 3 months release cycle since they launched AIR on mobile;
it runs on Android 2.3+ devices only; and only devices that are matching the minimal requirements defined for the AIR runtime; that is to say, most of the smartphones and tablets, except cheap ones like ZTE products. When a device is not considered as powerful enough by adobe, the AIR based apps are not displayed in the stores.
Some recommendations:
The best way to organize your code is to create a project for each OS, with specifics assets (icons by example) and a specific manifest file (app.xml), and put all of your application code in a library used by these two projects. It will allow you to test your code (Flex mobile project can't be unit tested), and will avoid you permanent modifications of the manifest.
Worflow: it's usually faster to develop for Android, and then adapt you app for iOS, because it's faster to deploy and test on Android device (although you may use the Adobe Simulator most of the time).
Use the latest release of Apache Flex; it handles the high resolution devices. Forget Adobe's release (4.7 and lower)
Test quickly and often on mobile, especially for the responsive aspects.
Use FXG instead of bitmap graphics each time it's possible (i.e. if they arent animated); it's lighter and very easy to scale.
Mad Components
Alternatively, you may consider using Mad Components instead of Flex.
Flex was not designed for mobile at first; MC was. So it's faster (looks like native), and much lighter (although you still need the embedded AIR runtime which weights 9 Mb).