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Advice on the best way to go about developing an app for Android and iOS as first project

Sorry if the title wording is not clear enough. I need to deploy a very simple app on Android and iOS for a partner company (app does not need to be in App Store or Google Play) to control some machinery via bluetooth. Interface needs to be very basic and only contain a couple of buttons and some text labels that display some information (and be able to read a QR code).
We are not a mobile development company, thus I don't have any experience building apps like this, but the required functionality seems simple enough to at least look into what needs to be done.
Now, the problem is that I only know C/C++ and Python (moderate experience with the Qt framework) and am not really willing to learn both Java and Swift. I might consider learning Swift specifically for a simple project like this, seeing as iOS development is very much tied to their platform, but Java is out of the question. I've looked around and there seems to be a way to write both of them in Python and deploy to each platform, but something tells me it's not really worth the incredible amount of problems that could arise. I need your help with some advice on how to handle this project:
Can a cross-platform app be developed with python(or C/C++) and deployed to iOS and Android (thus halving the overall development time) whilst keeping a sufficiently tidy aspect and bluetooth communication?
If not, can I develop an Android app using C/C++ or Python without immense hurdles? I'd prefer Qt as i'm already familiar with the framework, but i suppose anything does it.
When developing an Android app under point 2, is it possible to see how the app looks like without installing it on the phone for every change in code?
Sorry if the post is too long, am really curios how difficult would a task like this be. I dont want to waste my time learning 2 new languages for just this project nor do i want to end up delaying the partner company with beginner problems caused by my scarce knowledge of a new language.

I really wouldn't suggest cross platform for this kind of project. The bluetooth stacks and APIs are going to be tremendously different, minimizing ability to code share. The UI stacks are completely different. Really using anything but the native tools on iOS can be particularly tricky. Python in particular is hard, because its not meant to interact with either platform. C would be easier, as both Java (via JNI) and Swift (via objective C to C bridges) can call C code. However the UI layers of the two are so different that it would only be useful for business logic, I would still recommend writing the UI in the native platforms.
If you were going to try and do cross platform, I'd suggest react native and javascript, merely because it's the most mature of the cross platform products. That said, their bluetooth stack is likely non-existant or poorly developed because its not the type of thing used by many of the type of apps that choose react native, so you'll likely have to dive into the deep end and learn how to make modules.
Given that this is going to be a company specific app not on an app store- do you actually need to support both OSes? Or can it be done on company devices of a single type? Pushing back on that product requirement might be your best bet.

Cross Mobile Options

I created an Android app. While creating one specific app was an interesting challenge, I'm now looking into creating a group of similar apps.
I'd like to create a group of similar Android apps and then move on to creating the same on tablets and iOS... (anything mobile).
I've considered doing so with a product called PhoneGap or doing a web based mobile app. Both of these options seem less than ideal. Doing the Android app I've been frustrated by Java's lack of control and low level constructs. Moving to something like a web based app seems like the exact wrong direction.
C++ is my language of choice. It has the ability to work at a low level, is highly portable across platforms, and has significant support for generic coding which would be useful for generating a group of similar apps. However, the Android documentation suggests to not use C++ unless your goal is porting existing code or dealing with computationally heavy tasks.
I'm leaning towards using C++ anyway, but are there other options I've not considered?
Thanks

You could in theory write your logic in C++ and then have UI layers on top that make use of it. If you are really comfortable with C++ that might be the way to go.
Almost any other parts (networking, UI, animation, etc) are better off being done in the native language of the platform. Use of cross platform solutions always limits you in some way, and usually leads to an application that is not as good as it could be for any platform.

Well, Google's recommendation to not use C++ is based on the following, I believe. C++ is low level, so you can get extra performance out of it if you know what you are doing. Google makes the reasonable assumption that many programmers do not. It is easier for an inexperienced programmer to do harm in C++ then to get a performance boost.
But, if you know what you are doing, it can help you. UI elements on both iOS and Android are implemented in their main language (obj-c, and Java respectively) so there is not a great way around that, but you can write core logic and other functions in C++ and it will be portable between them (iOS can use C++ directly and Android can use it via the Native Development Kit).
There are a few other options available. The one I ended up using is Appcelerator Titanium but please stay away from it. If your project gets complicated or large at all you will hate yourself for choosing it, as I did. Another interesting one that uses C++ instead of Javascript is Marmalade. I haven't used it though, so I can't comment on it.
A non-free solution that I hear good things about is Xamarin, who have ported both environments to C# and a .NET using Mono. However, you still have to write two versions of your code for the UI as far as I can tell.

An approach to porting a project to another platform

I am an intern at a company trying to push an android and iPhone out out within the next 5 months. Today, I received information about my first "real" assignment which will entail porting the iPhone App to the Android platform. Here's my problem though: I've never seen a single line of Objective C code and I only just started programming in Java and for Android devices last wednesday.
So how do I go about porting an application? Where do I start? How do I best organize myself and get an overview of which tasks to complete and when to start working on them ?
tldr; How do I port an application to another platform?

Word porting means in effect creating an application on another platform (in another language if needed) that maintains the same functionality. As iOS and Android use different languages and internally very much different operating model, you cannot simply take iPhone code and translate it line-by-line into Android.
What you do need to do is analyse the functionality of the iPhone app and create an app for Android that will perform the same functionality. Do not approach this as a direct "porting" project, but rather as a new development project. You may be able to translate some business logic one-for-one - but anything related to the user interface (and, most likely, to any back-end server communication if you have any) will need to be written from scratch. You may encounter certain things that are present in an iPhone but are not supported at all in Android, or are very complicated to implement, so try to think how to substitute them with whatever Android does support.
The biggest problem you'll encounter with Android is the multitude of screen sizes and versions, each of which may behave differently and support different things. I suggest you start from the beginning and do one screen at a time, adding functionality step-by-step until you get the desired app.
5 months is a long enough period of time to complete the job for almost any app. Good luck!
P.S. I have gone through this exercise myself: having an iPhone app I had to "port" it to android platform. Using the approach I described, it took me about 2 months to complete the android app, which initially took about 3 months to create on an iPhone platform.

Is there a technology which makes it possible to develop a game for Android, iOS and Web simultaneously?

As the topic states - is there any technology that would let me write code for a simple commercial 2D game which could be then compiled to work well on Android, iOS and Web browsers or at least two of them (e.g. Android and iOS)? There is so much buzz about cross-platform nowadays that I was wondering if I'm missing something.
My goal (set by my producer) is to make this game for all of these three platforms, and so far I planned to use:
- Web browsers: Adobe Flex,
- Android phones: Java (since my favourite C++ is recommended only for short snippets),
- iPad/iPhone/iPod: Objective-C (are there any alternatives?).
It pretty much means re-writing the same source code three times. Is there any way to speed it up by using a technology that would work on at least both of them?
However, I don't want to use Adobe Flex for all three (though it's possible), because it requires Adobe AIR (works only with Android 2.2 and higher) and not a lot of phones have it (it's totally different with browsers where 98% of people have Flash).
I don't mind adding some platform-specific code for each version, of course.
Also, if you have any suggestions about choosing a fancier technology for any of the platforms (maybe some nice frameworks?), I'd really appreciate that, too.

Take a look at Corona and Moai both are Lua-based frameworks for game development targeting multiple platforms.

I would like to say that Multimedia Fusion was capable of doing this, but it isn't quite ready yet. There are currently a number of runtime exporters for the product which allow you to export your game to multiple target platforms which include flash, java and iOS at the moment. XNA and Android exporters are currently in the works. I should probably mention that I am only affiliated with these guys as a happy consumer of their products. It is probably worth checking it out even if they can't do everything you want yet. If it's not suitable for your needs it is still a very good choice if you wish to rapidly prototype your application.
See:
http://www.clickteam.com
On a side note, personally I would recommend against going down the js+html5 route, particularly if you are targeting mobiles. I should probably stress that it's simply an opinion I have and that there are plenty of people here who will disagree with me. In all javascript games I have played, I have felt the garbage collector. The issue is that without control over garbage collection it is free to run when it feels like, causing infrequent but very obvious pauses in the middle of your game. You can work around this but I don't see why it should be that difficult. I can definitely align with the ideals of being able to write the thing once and run it on all platforms, but I can't see it working just yet.
To offer some advice assuming you find no suitable tools for the job, your aim is to maximise reusability. This means all of your games resources and levels should be well defined as independent resources. For non-critical logic you can make use of embeddable scripting languages such as Lua, which will maximise your code reuse. C (or C++) code will also be reusable on a lot of platforms, and might be a good choice if you are familiar and confident with the language.

I'm personally using Phonegap and Zepto.js. But you may have more luck with jQuery mobile. Phonegap is nice because its website will compile the apps for you.

1) If you write your game in C++ you can use it for iPhone & Android (NDK) as well. Preferably, you write your game engine in C++, than you can use a OS specific layer for UI stuff..
2) Implement your game in HTML & Javascript. iPhone/Android users will have to use a webbrowser to play your game. For iPhone, you can even create a launcher, that looks like an app, but actually is a webview with HTML & Javascript

Unity3D should be able to do this for you, if you purchase some extra sprite addins to handle 2D (like Ex2D or SM2 or Toolkit 2D). Also right now until Apr 8, the iOS and Android license is free.

Game Maker Studio. It has a package that let's you deploy on all of the platforms you outlined.
http://www.yoyogames.com/gamemaker/studio

Starting Android Development: Native or cross-platform?

I am an experienced professional programmer who wants to delve into Android programming. I also wish to investigate cross-platform programming using tools like PhoneGap or Titanium.
However, I am a bit in doubt of which learning strategy is best.
One approach is to get a good feeling of the Android environment and later on explore the possibilities of the cross-platform tools.
Another approach is to jump start using say Titanium (which to me looks like the better option of the two mentioned) and then after a while look into the underlying Android building blocks. The reason why this approach seems worth considering is that although I have earned my living on programming for 20 years, I have no experience whatsoever with Java. And the feeling of getting something done has always been encouraging to me.
What do you think? Does option 2 make sense, or would it be more sensible to get an understanding of the Android environment first?
Thanks in advance,
Martin

I think that all depends on what will you develop:
If you want to develop simple interfaces (parsing XML/Json/...) with some forms and nice transitional effects, then Titanium is yours.
However, the most advanced functionalities aim the iOS platform. For example, the augmented reality module or the push notification are not supported for Android.
On the other hand, if you want to develop advanced interfaces (Games for example), then you have no choice: Android SDK is the best way (you can use Flash for Android but it doesn't support very first Android OS versions).
In all cases, you have to understand how the Android platform works.

I had a similar decision to make, although I am not an experienced programmer like you with vast experience , I had no java knowledge and I needed to write an android app for a project in grad school ,and i'd tend to agree with you on which is the better option , although reading the dev guide and grasping the basics will be a must. And like Zakaria says , it also depends on what you plan to develop.
in my case I learnt basic java first , then used the SDK for my project. Its not that big a learning curve actually , I did not find too many problems with the API.