Develop Reference

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.

business processes Framework (Xamarin or ReactJS)

maybe someone can help me. In near future i'm going to develop a business processes application like this :
https://play.google.com/store/apps/details?id=de.semture.cubetto
https://play.google.com/store/apps/details?id=com.showgen.processcraft
Now i would like to know if there are some already existing Frameworks or projects for that. I just want play arount with that subject to get a feeling how it works and what i have to do. I'm planing to make it available for Android (highest priority) and Web (Ios and windows arent so important right now).
So my first question is. Are there any Frameworks, libs, project availbe for something like that?
I've already searched for some frameworks but without no success...
And the other question would be what Tool or language should i use ?
Currently i'm working with Visual Studios 2015 Xamarin (xml & C# based language). We all know that i can make crossplattform apps with xamarin. But some minutes ago i've heard that there is a language/Framework named React.JS, that is also for android ios and web apps.
Now my second question:
which one should i work with ? Xamarin or React.Js ? Which one would better fit to my project and what are the main differences ?
I hope someone could answer that :)
Thanks in advance

This really comes down to personal preference and what you are trying to accomplish. If you are a C# developer, then Xamarin might be your best bet for android. With using ReactNative, it will be a little easier to create your web app from since it uses React. If you are trying to have a native feel for the android app, you will still have to know some core android development for both platforms. If you aren't super worried about the look, feel, and performance of it being native, then you can look into ionic which is built on top of Angular, and this you can use as a web application as well as build it for android.

What should i select for my mobile applciation development? Native way or cordova or react,Node.js like things

I want to develop application in android and iOS both.
But i am confuse between native development and development using react and node.js etc.
Please help me to choose (If possible specify reason).
P.S Here cost is not an issue.

If you need high performance and attractive UI and don't want to be blocked by some functionalities that may not br provided by cross platform, I recommend you to use native platform. But if your app doesn't need to be very attractive and doesn't need too much processing, then you can use cross-platform. Actually for many features you need to add plugins if you are building cross platform app and adding number of plugins makes your application slower.

OK, well there isn't much data to go on, but there are several options if you want to write cross platform apps.
There is:
Sencha Touch - HTML and JavaScript
PhoneGap - HTML, JavaScript and CSS
QT - C++ and QML
Appmethod - C++ and Object Pascal
Xamarin - C#
Visual Studio - looks like you can do C# or C++, or Unity for games.
and probably a lot more...
Why would you choose one of these instead of writing in the native language for the platform?
Well, the pros seem to outweigh the cons. If you are targeting several platforms, I would choose one of the options above, simply because you only have to write everything once. If you did it native for each platform, you would write everything twice or maybe three or even four times. Using one of the above tools will be much easier and save you time, and they might be just as seamless and workable as native development.
To simply answer your question, If you would like to be able to write your app once, and be able to manage all future updates by managing only one code base, do cross platform using one of the above tools. The only downside is that you might have to learn a new language (but with a place like Stack Overflow, learning new languages is pretty awesome). It will save you time in the long run.

Android Cross-Platforming

I want to know more about Cross-Platform. I'm currently working on my thesis and decided to make an Android Application but not all target users uses Android device. So, We've come up with an idea to Cross-Platform the android application.
I have read the same topic but it didn't get to me too well. iOS / Android cross platform development. I want to know if there is another way than using the frameworks discussed in the link.
I want know what is the best/shortest way to cross platform a Android Application?

Cross Platform tools are in my opinion not a good idea at all. Android is Java, and iOS is Objective C. Android can use NDK to use a C/C++ library so theoretically if you did most of your code in C/C+ it could be used on both sides. I think two natives is more in order. Study NDK to see what could run on both devices. Lets say you built your app as a C++ Library except for UI interactions. Then in theory the library should work on both sides. C/C++ a lot easier on iOS than android however.
Also it really depends on the dependencies your app will have. Lets say you want to use a library but its only available in Java or C++ how does this effect your decision.
You might also consider designing your app so that it just captures data on the devices and the actual processing of the data takes place in a web service.

Another way is use Mobile Web HTML5 Framework like Phonegapp, Sencha touch and more.
Although web technologies don’t perform as well as native, but it is a useful thing that you can try.
See Choosing Mobile Web HTML5 Framework and http://operationproject.com/2011/adventures-in-html5-part-one/

Android application are apk files that are basically zip file that contains dex/odex files and all other resources that you may wish to add.But I think you can use any coding language to develop as long as you have IDE that converts your code to apk and dex .And most important of all your programming language must support corresponding api or must have something similar to cross compile.The reason Google used Java for Android was they felt it is convenient to do it(read it during case Google v/s Oracle)
Personally I feel cross-platform is good since it increases the developers base and understanding of the System (here Android).And I think the same analogy would go with other Systems as well.

MonoDroid VS Java in android development?

I know C# rather well and just love Visual Studio as IDE. :) Yet now I want to start developing for android...
I found out about MonoDroid and wanted to ask if it has any downsides to it that would make Java more preferable, or should I uninstall Eclipse and dive straight into MonoDroid?
If I understand right, MonoDroid deploys/compiles native android applications and does not need any additional .net-like framework or anything?
Are there any significant limitations to what I can do with MonoDroid? For example, having the app run in the background or using some external .net libraries for image editing, etc. ?

I've been worrying about the same thing - productivity in C# instead of playing with an unfamiliar language, vs developing how the OS developers intended it to be.
Its easy to list pros vs cons -
pros (of monodroid, for C# developers)
familiar dev environment, can develop using Visual Studio
C# instead of Java
Reusable code assets - you can use a lot of code in your iphone project or Windows phone 7 project using monotouch and the WP7 SDK.
cons -
debugging could be difficult, due to lack of api documentation from Google. Will have to depend solely on monodroid documentation.
there could be a lag when it comes to latest cutting edge features - safe to assume that the monodroid team will require some time to wrap around the latest android features every time there is a new OS release
availability of libraries - I am not sure how you can use the open source libraries that would have evolved around the android platform, that could cut down on development time

Much of the documentation available is in Java: so if you run into difficulties with phone behavior when using MonoDroid you won't really find that much help or debugging information so you may want to stick with Eclipse.

There's a lot more than just a set of wrappers running under davlick, truth to be told, there is much more of a horizontal relationship between MonoDroid and Android;
When did using the same language as the OS developers become a big issue? There's lots of C++ programmers wondering how to use BSD or SVR5 and many C programmers who want to know what the heck to do on Windows++...

If you will write in c# anyway you will be have to wrap it into a Java code, so what's the point ? Also you may head with a very difficult issues while trying to understand the APIs who written for Java programming...

Here are some points that you can mull over:
Android applications are predominately written with Java. The Android SDK itself is natively written in Java.
Working in Mono may not provide all the functionality available in the Java SDK.
If you are a C# Developer you wont be able to find, in Java, some of the (cool) features available in C# (like Property Delegates etc).
Code written in .NET can be re-used for other environments - this may save a lot time that would have been spent learning a new language/environment (like Objective C), and coding in it.
.NET extends the Android development stack with it's existing libraries and API's.
I think both are good for certain reason. It will be very hard to say which one is preferable for Android development - in the end that is up to you too decide.

Also note that any release build using monodroid adds an additional 4mb to the apk filesize and increases app startup time with a few seconds.
For simple apps this can mean a 500-800% increase in filesize - whic is pretty bad in my book.