I've been hired to develop a mobile framework for a webservice created by my employer. Ideally management would like to have some reusable components that can be shared across mobile platforms (initially iOS & Android, probably Windows Phone 7 at some later point).
I've been wondering how feasible this is. One of the requirements is a native interface, so we would use Cocoa Touch on iOS & whatever (Java-based) toolset is used to create a native UI for Android. The application will interact with webservices, mainly the ones that we've been creating internally. The webservices have been developed in .NET.
As far as reusable components go, I guess we could use some C++ code to make webservice calls and perhaps even more of the backend of an application, yet I wonder if this would be a good approach. Apple's Foundation Framework has some excellent capabilities build-in to access webservices, not to mention other open-source libraries, e.g. ASIHttpRequest, SBJSON, etc... I guess the same would be true for Android (though I have no real Android experience for now). Also, when looking at projects done by companies like Google, Twitter & Facebook, each of these companies offers native libraries built for the major mobile OS platforms. If the big companies take this approach, it seems logical for us to follow suit.
Perhaps we should focus more on a general architecture that we should offer across platforms instead of an implementation that can be shared.
Would anyone advise us to make use of C/C++ to develop such a framework (shared library) for the mobile site of our webservices? If so, why?
It really depends on what level of customized code you want to have. I worked at a game company previously, and we made two games for both iPhone and Android, and at least 90% of the codebase was shared between the two platforms in c++ code. Sometimes it is significantly easier to implement elements with specialized third-party libraries, like for Facebook and the like, but maintaining that code means continually doing it for both platforms. That was one of the reasons why we even implemented our own UI objects in c++ for our games. Because even though the initial setup would have been easier to do with Interface Builder and Android's XMLs, the maintenance and tweaking necessary ended up being significantly less because we went with a shared codebase.
In short, I would highly recommend writing any shared customized code in C/C++, and things that are significantly easier in their native codebases (java for android, or obj-c for iphone) and you don't expect to change much, to keep separate.
Depending on which WS protocol you use it may be more or less hard to do, but anyway I see little advantage in doing that in C/C++ for a mobile platform.
If you were using SOAP, I'd never consider C/C++, even for a desktop app. I already used SOAP libraries for C++ and they are a lot harder to use than their Java/.net counterparts, and the way they are implemented (mapping SOAP objects to C structs) is very prone to crashes if the format changes. Not to mention that you have to recompile your client when the WSDL changes.
As I understood in your case you plan to use REST. I never found a good REST library for C/C++, but recently I did a desktop project in which I implemented a C++ REST client using simply WinHTTP (in Windows) and libCURL (in Linux). Of course, they provide just the HTTP part, so I had to add cppdom for XML parsing. If you use JSON, there are many good libs like jsoncpp, libjson.
I'd say to you that even in a desktop environment it was harder to do than would be in .net or java, and was only done this way because it was part of a larger application already written in C/C++.
Anyway, you'll have more work and not much advantage since all those modern mobile platforms provide rich libraries that do the same thing, and probably the user of your API will develop in the platform's main language, so you'll have the double extra work of implementing the WS access code AND the binding code. As I assume all (or at least most) of your logic is in your server, not the client, there's not much common code between the platforms to justify using C/C++.
Related
I am currently planning the development of a multiplatform app, and I am not sure wich way to do it fits my requirements best, since all possibilties I could think of failed to satisfy me.
First I want to write an app for android, which should feel like a normal typical android app. So I want to use the standard actionbar and android design look and feel in my other gui elements. After finishing the android app I am planning on developing an ios app, which should have a different design, so i am going to redevelop the gui for this anyway.
But I don´t want to rewrite the other code wich represents the intelligence of the app, independent from the gui. I came up with the following possibilities:
1. Java GUI With native library
Here I abstract all the code of my app in a C++ library (since as far as I know ios supports the usage of c++ libraries too) and develop the gui android typically in java. The library would than have a function to start and would inform the gui about every change via callback functions.
Pro
I can reuse all the code that would be the same on both platforms. I just would implement the gui seperately
The design of the android gui is straightforward as I want it to be. It looks like typical android because it is typical android.
Cons
I dislike the usage of JNI very much. Especially the signature and names of the callback functions (calling java functions from c++) are not checked at compile time and require a lot of manual work. If I rename a function and forget to rework the native part I only notice this mistake at runtime.
2. Build the GUI on the native side
Here I had difficulties finding out what is possible, especially for 2.2
2.1 Use Qt
I have only a few first step experiences with Qt in general but as far as I understood i would have the following pros and cons:
Pro
Reuse most parts of the code for ios and Android. I would than redesign the gui for each platform to make them feel natural. I can´t evaluate how much qt may even assists me at doing that
Cons
I have to copy the android gui by using other qt widgets. This is more effort and I don´t know if one can replicate the android gui elements (like the actionbar) so that the user wouldn´t notice it.
2.2 Using the android framework from the native side
I dont know if this is possible at all, I wasn´t able to find this information. Can I use the class "NativeActivity" and use the android framework to build the gui and use e.g. the actionbar? If this is possible somehow it would have the pros from 1. and maybe wouldn´t have it cons?
Do you have any feedback to my ideas or maybe even new approaches I didn´t think of? How do other multiplatform apps like WhatsApp solve this problem? Do they have redundant code for each platform?
Thank you,
Tobi
I would say that it depends very much on your application requirements. By my opinion, a better solution is to develop a separate application for each platform using recommended SDK's for that platform, and implement in native C++ only the time consuming data processing algorithms.
Application runtime on mobile platforms is not so straightforward as on desktop platforms. You should take into account background and foreground processing, specific application life cycling, accessing system resources such as network, file system, etc. And all these issues do differ on iOS and Android.
Regarding possibilities that you listed.
Qt/QML is ok only in case two requirements are met:
1.1 Your application is a foregroud application without any background operations.
1.2 You purchase a commercial Qt license because only commercial Qt can be submitted to Apple iTunes app store (even GPL apps are under
question).
Using NDK Native Activities on Android with cross-platform C/C++ backend. Android NDK API offers much less API then Android Java SDK, so a lot of things you will have to implement or wrap manually. It is a hard road.
Mixing Java code and C/C++ using JNI gives you more of Android SDK API. But you should remember that an Android activity's life cycle is not somewhat that you're used to deal with when developing on C/C++.
Approach that we are using
We've been developing an application with a huge amount of cross platform functionality that should work on Windows/Linux/Mac OSx/Android/iOS. We're using the approach as follows.
Cross-platform core is written in pure C++.
We have adaptors to GUI interface for each platform.
On desktop we use Qt as it reaches all desktop platforms with minor adapting to each platform.
On iOS the GUI is built using iOS SDK with Objective-C and C++ core is linked as a Framework. Still, we had to patch our core in some way for iOS background requirements and so.
On Android we wrap our C++ core in a background process and build all the GUI using only Android Java SDK. Foreground GUI activities interact with the core via local sockets, so we don't need to bother with activities life cycling in our C++ core. But the adaptor is a litle bit complicated.
Nevertheless, both mobile platforms often require workarounds and adaptations in C++ core which add a number of #ifdef'ed branches in code for each platform.
I've been searching solutions for my enterprise apps, at least 3 platforms need to be supported, which are iOS, Android and Window Phone. After a whole day's search, I finally set my eyes on 2 promising cross platform solutions, one is monocross and the other phonegap.
monocross seems to use c# and .net at all, is it possible to access native libraries and languages? I read somewhere it's compiled directly into binaries that can execute on target platforms.
And about phonegap, it uses webviews on each platform to provide the capabilities of presenting user interfaces to final users. As it's implemented via interpreted language and high level apis, the performance may not meet our needs.
Finally, we(my team) decide to give it a try with mono, the architecture is illustrated as bellow:
+++++++++++++++++++++representation layer++++++++++++++++++++++++++
[monotouch,monodroid,silverlight]or [native gui calls] or [html5/js/css]
+++++++++++++representation controller/business logic layer+++++++++++++++
[ mono/c# ]
++++++++++++++++++++++++++++server side+++++++++++++++++++++++++++
[ the cloud ]
I want to use mono/c# to write some common purpose business logic and data structures, and when it comes to some common platform features, like storage service, notifications, I'd like to wrap them up on each platform and expose uniform apis for c#(business logic layer) to use. As to the representation layer, we decide to choose from the 3 optional solutions listed above.
To make this happening, first I have to figure out if it is possible to call native frameworks.
So, my questions are:
1, How does mono work, I mean, are the c# codes compiled into binaries that can be executed directly on iOS, Android and Windows Phone?
2, Is there a mechanism to make native invocations? Like in cocos2d-x, I can call java methods via JNI, and in iOS, c++ can call oc directly. Can I call cocoa touch stuffs in mono with c#?
3, Is it possible to manage all these stuffs in one single project, and how to build them?
4, Are there any better solutions?
Any suggestions will be appreciated, thanks for your patience!
I wonder why Xamarin does not land on the first page of your search result,
http://xamarin.com/features
But that's what the Mono guys created for the C# developers that want to target mobile platforms. MonoTouch and Mono for Android are there each featuring a common library base with Microsoft .NET, and also platform specific bindings.
Your non-UI code should be able to be used in portable libraries and share among them. Microsoft's portable library is Windows specific, and right now I am not sure how much Mono guys can embrace that, but even if PCL fails, you can create multiple platform specific projects based on the same copy of source files (which I did in #SNMP). The remaining task is to develop platform specific UI for Windows Phone, iOS, and Android.
There are tons of articles showing the features,
http://docs.xamarin.com/
and also many successful apps
http://xamarin.com/apps
The best way to learn a product is to try it out (for free in Xamarin's case). This also applies to MonoCross (which is a framework built upon Mono).
I am not familiar with PhoneGap, so you need someone's advice on that.
Disclaimer: this is not a complete answer - but I do hope it answers at least part of your question
I encountered a similar problem when I started cross-platform dev using the Mono products 18 months ago.
The approach I've built since is called MvvmCross - it forked off of MonoCross a long time ago - now shares no code with it (but maybe we'll team up again one day!).
The approach uses PCLs to share code. This is not entirely painless, but is easy after you've done a few setup steps - http://slodge.blogspot.co.uk/2012/12/cross-platform-winrt-monodroid.html
You can learn more about this approach on this video: http://slodge.blogspot.co.uk/2012/12/mvvmcross-video-presentation-xaminar.html
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.
I am planning to do a project on Peer to Peer photo sharing on Android. My professor wants me to do that using some language other than Java or C/C++. Is any of Erlang, Haskell, Ocaml,
Scala, Go helpful to build an android app with following functionality?
Ability to design a GUI for android to view the pictures to be shared
Support for socket communications to transfer the pictures?
Since Android relies heavily on Java, Scala would be a good choice here. Scala makes interoperating with Java code easy and runs on the JVM. On top of this, it is a nice functional language with an interesting type system, so it will be a good learning experience. (So will your other languages, but Scala is probably easier to use on Android.)
Check out Scala Programming for Android, which describes how you can make Android applications in Scala.
You can compile and execute Go programs on Android (or ARM in general), but you can't actually use the Android libraries. So, writing services or GUI applications for Android in Go is currently not that easy. I am not sure about the other languages, but I think Erlang, Haskell, Ocaml, etc. have similar problems (if they even provide an ARM compiler).
Therefore it's probably best to focus on a JVM based language. Most of the examples and other applications are written in Java, but Scala is also able to access all those APIs. So, I would either use Java or Scala.
There's also this JVM-based functional, dynamic, lisp-like language Clojure, which some people seem to like a lot. It should be possible to use it to write Android Apps.
Well, in my view, it depends on what you want to really use the language for as regards your project. Photo Sharing: are you planning on using Web based tools for the client, i.e. JavaScript, HTML5, CSS3, JQuery Mobile (http://jquerymobile.com/), sencha Touch (http://www.sencha.com/products/touch), Phone Gap (http://phonegap.com/),Titanium Appcelerator OR you want to use native stuff like Java, J2ME, e.t.c. Then if its web based (which would make things easier in my view), the language you are referring to in this case would be on the Server side. So in my view if you just need the language to web-serve photos and stuff, then it would not matter which one you use: really depends on your liking. I am pretty sure that Erlang, Scala, Java and the others all have capability for developing great web services. However, the conditions you put as below:
1) Ability to design a GUI for android to view the pictures to be shared 2) Support for socket communications to transfer the pictures?
Suggest that you were referring to a Front-End technology to use. You cannot use Erlang to create GUIs on Android, if i am right, you may not also be able to use Haskell and OcamL as well because these technologies cannot run on the device. For GUIs on Android, you can only use Java, OR you can use Widget Technologies like Opera Widgets OR you use Web based stuff like i mentioned above. However, you should know that using JavaScript Libraries, HTML5, CSS3, e.t.c. is the quickest and more manageable way of developing Apps on any Device. I even wonder why you are talking of Socket Communications !! Am i getting you right ? you want to develop a Photo Sharing App which transfers Photos over raw Socket Communications ? Well, i am NOT sure how many apps out there for Android are doing raw Socket stuff, but i am pretty sure that many (http://androidapplications.com/) are using HTTP Protocol, as in Web Services. Consider looking into web services than raw Sockets. I am pretty sure that even apps developed using native Java, uses HTTP (Web Services like SOAP) to communicate with a remote Server, be it weather apps, location-based stuff e.t.c. Otherwise i guess you should concentrate on Java, for now.
I'm doing some initial research on smart phone development, and I noticed that Android and Windows Mobile both support c++ for application development. I was curious if anyone had any experience trying to manage shared files between both Android and Windows Mobile, and to what extent that code can be shared? e.g. no user interface can be shared, but web service and business logic classes can be shared, etc.
I can't speak to the WinMo side of things, but on the Android side you should really really really avoid using native code for anything except performance-critical processing algorithms. JNI/NDK stuff does not play nicely with the normal Dalvik lifecycle and can be a source of all sorts of ugly unpleasant bugs and memory leaks. From what I understand there also aren't on-board NDK libraries for more complex high-level functionality like HTTP (just more basic/performance-oriented libs like libz and OpenGL), so you'd probably have to compile that stuff and ship it with the app as well. I would definitely not recommend coding your web service classes in C++, even if it's technically possible; it'll be less buggy and nicer to write C#/Java and you should be able to make mostly the same architectural decisions for consistency.
That said, if you have a performance-critical bit of image processing code or the like, it actually can be fairly straightforward to get that working across Android to other platforms (I've seen it done quite well with some image-processing C code used in an iPhone app and then used via the NDK in an Android app).
Check the documentation on the NDK for details on what it can (and can't) do, and see similar SO threads like this one.