My company is building a Flex application that we may need to port to other platforms:
Silverlight (likely)
Mobile (maybe -- iPhone: Objective-C , Android: Java, etc.)
Desktop (maybe -- AIR, .NET, etc.)
TV sets (maybe eventually)
Currently, I’m looking into application frameworks to build upon and I’m torn between pureMVC and Swiz.
I LOVE swiz for its simplicity and how it just gives you a way to hook things up and then apply your own patterns. From a flex-only perspective, this is my 1st choice.
But, PureMVC is platform-independent and has already been ported over to most of the platforms that are mentioned above. How valuable is this portability? Will it really make our lives significantly easier when it comes to porting and developing/maintaining multiple applications? If so, then it seems like PureMVC is the way to go.
Alternatively, since Silverlight has the most definite business case for porting of our application, maybe we could port Swiz to Silverlight? I'm not too familiar with which AS3 language and Flex framework features Swiz depends on and whether they are available in C#/Silvelright. Would this actually be possible?
Thanks so much!
Karthik
The way I see it, if you used pureMVC you could port to a new language, without too much trouble (other than what the new language will give you) your commands, mediators and proxies, provided you program your mediators to an interface, instead of a concrete component implementation, and the proxies use a services layer to get the data from server. That way you'll only have to implement the components and the service layer in the new language.
A quick look at the Swiz framework:
uses the flash event model (see CentralDispatcher)
uses some flash.net, and mx.rpc classes (see net and rpc swiz packages)
PureMVC framework doesn't use the flash event model, and eventual flash.net/mx.rpc references would normally appear in the service layer. On the other hand Swiz seems to be aimed at taking full advantage of flex, and the mxml format, so it might get the job done faster there. So you might also want to consider using Swiz for flex and PureMVC for the other languages.
Any framework, including Swiz, can very easily be ported to just about any language. Actionscript is touring complete, so theoretically any code writen in actionscript can be transformed into another touring complete language. For example, we use the Swiz framework in our mobile apps, which get cross compiled to run in iOS. There are many other open source cross compilers for a variety of languages, as well as Adobe's Alchemy project.
The only thing that is not easily portable in Swiz the usage of runtime metadata tags. This can be solved by using an advanced search and replace utility, or a custom transformation framework to convert custom metadata tags to their native code implementation. Hopefully we will see some cool new open source tools for this soon, now that Flex 4.5 was released with custom compiler hooks.
In short, I wouldn't even take portability into consideration when deciding on a framework. Choose the one which is most comfortable for you or your developers to use. I personally prefer Swiz myself.
Cheers!
Related
I have recently regained some interest in learning Qt, but have the following doubt:
Does Qt have enough classes that are not GUI-related?
For example, Python is "batteries-included", .NET is definitely "batteries-included", and as far as I have seen, Android API also has a lot of classes to design and implement application/domain logic, not directly related to visual presentation.
The main reason I am asking is because I don't know C++ and don't plan to learn it deeply (too much time needed), so if I had to take third party C++ libraries all the time and struggle to use them inside Qt projects that would be a strong point against going ahead.
The intended use is mostly to create small desktop apps for personal use while gaining insight on software design good practices - a profession I am slowly migrating to.
I have already used some Python/Pygtk (without IDE) and WPF (in VStudio/ExpressionBlend). In both platforms, most of my work is related to scientific computations, image processing and interactive scientific visualization, and there are good libraries for that either in Python (Numpy, Scipy, Matplotlib, Pandas, PIL, cairo) and .NET(AForge, alglib, System.Media.Media3D). I wonder if the Qt ecosystem is so complete in that regard.
Qt isn't a language in itself, so you can't compare it to Python or .NET. With that being said, Qt does provide general-purpose classes like containers, a Unicode string class, character set encoders/decoders, multimedia, device and file I/O, etc. All these modules are fully documented.
There are also some external modules available for Qt, like Qwt which provides widgets for technical applications.
For other functionality where something Qt-specific isn't available, you can obviously use another appropriate library. Like OpenCV.
Oh, and you can use Qt in Python too, through PyQt.
As far as I know, Qt doesn't have image processing libraries. For that, you'll need to use something like OpenCV. Qt does have libraries for loading most common image types.
However, Qt does extend beyond just GUI classes.
There is a database module that's quite convenient. The concurrency/threading classes are nice. I've enjoyed making use of the Qt Networking classes. The FileIO classes are alright.
These classes/modules are all useful for making platform-independent code. Things like image processing are mostly algorithmic and tend to be platform-independent by nature. So I think they fall out of the scope of the Qt framework. It shouldn't be too difficult, however, to simply find a library that does what you need and link that in to your project.
A lot of the Qt Core services that heltonbiker and Nikos C. mentioned, can be thought of as extensions to C++, a little like std. Although I often prefer the Qt implementations myself. But Qt has gone much further with their libraries, with the I/O, and web services etc...
The QtXML library provides reading and writing of XML files. Traditionally we had always used xerces, but the Qt XML library is almost as simple as .NETs.
The QtNetwork library offers TCP/IP and other networks services
The QtMultimedia library performs playback and recording of audio
and video content to the use of available devices like cameras and
radios.
The QtSQL library interfaces with SQL databases.
And there is much more than that. Although these are probably services that are used to most. The other benefit is that for the most part the implementations are cross platform. So for example using the I/O services does not require you to write separate code for Linux and Windows. That is a general rule, and there are exceptions. But I am sure most people would agree that any of the services they offer are easy to use, and well documented.
Happy coding.
Qt provides ample abstraction besides UI - it comes with a set of functionality enhancing features that come with certain usage paradigms.
Container classes - shallow copy by value, copy on write
Implicit sharing for containers and certain data types
Event driven, signals and slots
A powerful and usable metasystem
Properties
Platform abstraction for a lot of functionality, from file access to network and multithreading
Cross platform atomics (not that important since C++11 atomics)
Settings API
Undo API
OpenGL abstraction (not necessarily UI, custom graphics)
Basic image formats and basic image manipulations
Qt Declarative, a.k.a QtQuick and QML markup (usable for all kind of structure markup BTW)
Dynamic plugin API
Platform abstraction and portability - same code, multiple platforms
High and low level multimedia - audio, video
Sensors and serial port
Unit test
XML, JSON, SQL
An outdated and hopefully soon updated OpenCL abstraction
Last but not least, a lot of 3rd party modules built around Qt fitting a wide range of applications
Honestly, all its missing is support for some more popular formats for file, media encoding/decoding and containers, some parallel and vector abstraction, USB, WIFI/NFC (in the works in an addon module) and it will be 100% versatile.
Note that you can also use Python with Qt, although I have no experience with that, Qt is a very versatile tool that allows for quick and easy application development - and since 5.1 supports pretty much the entire market, with the addition of Android and iOS to the list of supported platforms. It is very useful for creating custom use applications for creative or research purposes.
Although not perfect for every task, Qt is easily the "best of the bunch" of tools you can use in this regard. Unbeatable in terms of portability and very thorough, if not a little bloated for the set of functionality it provides. And finally, it is free, you can even develop commercial applications under LGPL as long as you link dynamically. All in all, it is well worth the investment to learn, the only downside is it lacks uniformity between the old C++ native APIs and the QML runtime, which is actively worked on and is based on JS, so the APIs are a bit different and some glue APIs are required to fuse C++ with JS and QML.
(just for the record, from the official site):
The Foundation: Qt Core Module
The Qt Core module forms the foundation of all Qt-based applications
with core non-graphical classes used by other modules.
Key Functions
File IO, event and object handling
Multi-threading and concurrency
Plugins, setting management
Signals and Slots inter-object communications mechanism
Benefits
Reduce development time and cost by leveraging a complete set of application building blocks
Develop portable code from the ground up with cross-platform functionality
I am thinking about using PlayN to manage "common code" in Java and use PlayN to generate iOS, Android, and HTML native versions of the common code.
I figure I could then use the playn-generated native code and link with actual platform specific code (such as UI).
In other words,
Common Code libs in Java-> PlayN -> Native Commond Code Libs -> Link with Native App
Is the use of Play for the above workflow/pipeline appropriate? Any challenges?
Thank-you...
Firstly, you have to specify what you mean by "native" code for the different platforms.
On Android, your java files are specifically compiled/prepared for dalvik. So they are already "native" of a fashion, no work needed to be done here. If you want to get C/C++ native code for Android using the NDK, you're out of luck. PlayN doesn't do this and this is a hard problem (going from Java to C++)
If you take a look at the Maven modular layout of how PlayN is intended to be used, it isn't difficult to define a Factory interface in the common code and pass in a platform specific implementation for each module. It's no big deal to support Android specific functionality this way.
For the HTML version, you can use HTML libraries no problem using JNI, although really garnering specific functionality of the browser I'd imagined of limited value compared to what PlayN has already exposed. The one thing that is useful is text/keyboard input, although I'd recommend triplePlay https://github.com/threerings/tripleplay UI library as they've solved this, and it's an active project.
As for iOS, this might be more complicated as the iOS module is a bit of a hack where the compiled Java classes are run through an JVM runtime for .net (IKVM) and then uses the Monotouch tools to compile the whole thing to native code for iOS. See https://github.com/samskivert/ikvm-monotouch
So for iOS, you won't be able to bind the code to any form of native version, and what you have access to via the toolchain method depends very much on what Monotouch has catered for iOS (quite a lot I imagine), and also what IKVM-Monotouch has supported (I imagine the bare minimum to get PlayN working).
I'm not familiar enough with the Flash pipeline to give you an appraisal, although I think that it's quite flexible.
The above answer is written assuming your app is actually a game. If it is not and you intend to use the standard widget libraries for various platforms on mass, it should be possible. Choosing a good MVP framework would be good here, and depending on the assumptions it makes on different host environments will determine how easy the whole thing will be.
I'd recommend reading and comparing https://developers.google.com/web-toolkit/articles/mvp-architecture and perhaps look at questions like What is your favorite GWT MVP Framework?
...although a lot of these frameworks might be GWT specific and not really have catered to being reused on other platforms.
I spent some time to learn C++/CLI, I feel it is powerful .Net language specially in interoperability concept. I think it will be great step if this language will extend its interoperability to include asp.net, till now the recent version doesn't support asp. But I don't know if there is a plan to do that in future version. Is there any reason that made the last version of C++/CLI can not deal with asp like C# or VB?
C++/CLI was never meant as a general-purpose language. It pretty much exists just for interoperability purposes.
If you have a C/C++ library that you want to use in your .Net application (be it your own code or something like WinAPI), C++/CLI is a good way to either create a managed wrapper for that library or to completely write the whole application, if that's not that much work.
Other than that, you should probably use C# (I think it doesn't make much sense to learn VB.NET if you already know C++). Other alternatives are F# if you think your application would benefit from a functional style. Or IronPython (or IronRuby) if you think you would benefit from dynamic typing.
And of course, you can mix the languages if part of the application would be better in one of them and other part in different one.
Another reasons against using C++/CLI at all are its weak support in VS (no IntelliSense) and the ability of C# to interoperate with native DLLs using P/Invoke.
To reiterate, use C++/CLI if you need to interoperate with native DLLs or already written C/C++ code. For other tasks, you should probably use C#.
The Visual C++ compiler does not support partial class, that is, until C++/CX come along with the help of WinRT projection. The one-obj-file-per-cpp tradition is hard to break.
Without the partial class feature, form designers need to edit the same file you are working on. That means parsing a file with a lot of irrelevant text, dealing with macros, etc, and most importantly avoiding bugs that would replace your important code as designer-generated. I can't think of many teams want to deal with that, especially for small teams like the Settings editor.
Besides, C++ parsers are slower than those for simpler languages. For web designers, if switching to a similair language can get a faster designer and compiler, why not?
I'm not sure if there's any reason ASP.NET does not natively support C++ inline within aspx files besides the development team didn't think it was worth the cost (I'm assuming this is what you mean).
You should be able to implement code behinds in C++, however. This should get you 95% of the way there, although you'll still need to code your pages in C# or VB.NET.
http://www.codeproject.com/KB/mcpp/helloworldmc.aspx (not my article, just a reference)
I am going to develop a new GUI for an existing C++ application. The application works on Windows and Linux, and the communication with GUI is through client/server.
What are the pros and cons between Eclipse RCP and Qt?
Some pros of Qt:
C++ stuff will generally perform better; however, this is arguable.
Qt is the base of Meego, the mobile platform sponsored by Intel, AMD and others; however, its current momentum seems not too high to me. This means you can also create applications for various mobile and generally embedded devices
There are a lot of Qt-based applications out there.
It has a WYSIWYG designer.
Good for small to large projects especially because of QtQuick, which allows the creation of small applications in no time and with almost zero knowledge about C++
Qt has an amazing wrapper in Python called PyQt (there is also the PySide of course), which allows rapid development and slick prototyping. People often use PyQt (or PySide) for the UI-side of a Qt application because of that. You can of course combine with ease Python and Qt in the same application taking advantage of all their strengths (but also weaknesses). This allows relatively fast and smooth development cycles even for large projects
Some cons of Qt:
The code of Qt-based applications make use of some elements that are not part of C++, which have to be converted into C++ by a special preprocessor called moc (Meta-Object Compiler) prior to the actual compilation. You and your build system have to take that into account.
Nokia (former owner of Qt, since it acquired Trollech) has sold it to Digia. However, this does not imply their involvement in the development of the open source Qt has changed.
Some pros of Eclipse RCP:
Eclipse RCP is far more than a graphical toolkit:
It sports a plugin-based architecture that can help distributing functionality among different components (plugins) and keeping control over dependencies among such components (plugins). Eclipse plugin system relies on their own implementation of the Java component system specification called OSGi.
It provides a mechanism to enable decoupled application extensibility called extension points.
There are many Eclipse plugins that you can use in your application and many of them have distribution licenses that are friendly to commercial products.
It has a WYSIWYG designer.
Some cons of Eclipse RCP:
Eclipse uses a custom windowing toolkit called SWT; on each platform it relies on the native graphical layer. On Linux, it relies on Gtk+ (although it's also possible to use Motif), which in my experience (and other's) has performance problems, mostly with widgets that are updated at high rates. Actually many of us embed Swing elements in Eclipse RCP applications to overcome performance problems while keeping Eclipse's extensible architecture; this, however, can bring integration problems. There's a version of SWT that uses Qt as backend, but its incorporation into Eclipse's codebase seems stagnated since October 2010.
Startup time (understood as the time elapsed since the application is launched until it shows up a window) of Eclipse RCP applications can be very long.
If you intend to integrate C++ stuff with Java by means of JNI, be aware that some people find it difficult.
Eclipse has lots and lots of bugs. Eclipse's bugzilla is a very useful resource for the RCP developer.
The more you want you Eclipse RCP application's look&feel and behaviour to differ from Eclipse IDE, the more troubles you will get into.
Eclipse RCP development has a big learning curve, in my opinion.
Using Eclipse RCP for small projects is basically a suicide (unless you are restricting yourself to only creating a plugin or similar). It is meant for medium to large and very large projects due to the complexity of its infrastructure, resource requirements and the above mentioned steep learning curve.
Eclipse RCP is not for mobile development because...it's RCP (Rich Client Platform). If you want to go mobile, this is not for you.
Both their distribution licenses (LGPL/GPL/commercial for Qt, EPL for Eclipse) are flexible enough for most uses, in my opinion. Nevertheless, I am not a lawyer, so I may be mistaken about that.
And of course, other factors like the experience of the developers, their technical skills, the size of the team, concrete requirements, etc, should be taken into account.
BTW, I have much experience in Eclipse RCP but only theoretical knowledge on Qt, so I may be biased/mistaken in my statements.
Now that Qt has an LGPL license I would choose Qt any day of the week over Eclipse RCP.
I have used both to create fairly complex applications.
Since you can use eclipse to develop c++, I am assuming that we are comparing mostly swt/jface vs Qt, and not the eclipse development environment itself.
Some things I have noticed having used both:
1) Qt has better documentation and samples
Other than some half-baked examples on the web, I could find little useful eclipse documentation.
2) Qt has a lot more 'professional' users
There are many professional companies out there using Qt as their UI framework. Given it's three platform support (Windows, Linux, Mac), it is very flexible, and has a lot of backing.
3) Qt tends to be more complete and mature -
Using Eclipse I noticed that quite often the controls, and packages that were available were only partially done, and not quite complete. They were typically developed for someone's use, and only coded as far as that. Qt's controls were almost always a complete design.
4) Styling.
Both Qt and Eclipse render using local platform libraries, so your UI will 'look' like other UIs on the platform you are running on (i.e. Linux vs Windows). However, Qt also provides fairly sophisticated styling functionality that allows you to easily alter the look of any control, and gives you much more control over the look of your application.
With the new declarative language (Qt 4.7.*) you are approaching WPF level of control which is really amazing.
5) UI Designer:
Qt has a much richer Designer that allows you to layout your form, and do basic testing without having to compile any code. The designer also gives you the capability to add interactions between the controls on your form. Ex. Click this button - disable this option
Eclipse also has a form designer, although my experience with it is limited. I did try to use it a couple of times with very limited success. Finally I coded every form by hand through code. That is painful.
6) Interfacing with existing source code
If you don't have this problem, then you are very lucky. Because Qt is c++ based it integrates seamlessly with legacy C and C++ code. Integrating Java and C is not easy.
7) Drawing Libraries
I tried coding some hand-drawn shapes using the swt libraries and was forced to bypass large parts of the swt drawing library, because of the cludge that was in there. Using Qt to do something similar was no trouble at all.
8) Tree and List Models
Eclipse does provide some nice out of the box functionality for propagated data into trees, and lists and things. It is almost as good in Qt, although a little trickier to set up.
9) Application Layout
Eclipse provides some nice functionality to manage 'view's (dock panels), and 'perspectives' (workflows) that if you decide to use them makes life nice and easy. Qt requires you to do this yourself. Qt does have dock panel functionality, but when building a rich application you have to set this up yourself.
Extra Note:
Qt has also provided some extra libraries to support things like xml, etc... So this helps bridge the gap a little between c++ and java for things like this.
One of the stated goals of the PureMVC framework is to avoid platform dependencies in order to be portable. Considering that because of language and API differences application code will always be heavily dependent on the platform, and that avoiding platform dependencies makes the framework reinvent the wheel and/or only provide a least-common-denominator feature set, in what way does the portability of the framework benefit me as an application developer?
I've worked with PureMVC. They're trying to implement their stuff in quite a lot of languages. You may be right about the least common denominator, but overall, it's not a bad framework, and I've seen a really nice AS3 app in PureMVC.
I don't think they're talking about portability in terms of porting actual code. The idea there is more that you're using a generalized MVC architecture, which you could apply to other projects and other languages.
They're trying to say that if you become familiar with the PureMVC pattern, you could potentially come into a new PureMVC codebase, even if it's another language, and you would already know the lay of the land.
You might also say that developers who develop good PureMVC skills are likely to develop good habits which will translate as they go from language to language. But then again, maybe not.. for the reasons you mentioned.
We've been using PureMVC on two projects now and in my opinion the attempted language-independence is quite a burden.
The promise of jumping straight in a project because the framework is already know does not seem relevant to me if the languages are not already pretty similar (C# to java would make sense, as3 to php not) -- I agree that it is useful to have known ways of solving things, but for that the 'plain' patterns are good enough.
However, I also don't really agree with the usage of the various patterns the project uses, so our choice to not use it on the next project might be related to both issues, and not just the attempt at language/platform independence.
PureMVC's portability will help you when you migrate to or reimplement in another language.
I can't count the number of platforms and languages I've written code for that are now extinct and for which, even if I still had the source code it would be mostly worthless and have to be rewritten from the ground up today, since the code was usually 100% platform specific.
But all application code need not be heavily dependent upon the platform. View components and services (the boundaries of your application) will necessarily be, but your application logic which is sandwiched between the boundaries need not be.
The scope of PureMVC is really quite narrow; merely to help you split your code into the three tiers proscribed by the MVC meta-pattern. There is no reason why this code has to be tied deeply to your platform in order to be optimal.
When it comes time to migrate, you'll appreciate that the framework actors and their roles, responsibilities and collaborations remain the same. This leaves you to deal with syntactic differences of the language, recreating the view components and services. At least you won't have to completely re-architect.
And for the case of reimplementing in a different language, imagine you're trying to capture a significant part of the mobile market with your app. The market is so fractured, you'll have to implement the same program on 2 or more of Windows Mobile, iPhone, Flash, and Java. Sure you'll probably have separate teams in charge of the apps, but why have a totally different architecture? With PureMVC, you could have a single architecture for all versions of your application.
-=Cliff>
PureMVC is the only real option for Flash Platform developers who choose not to use the Flex Framework. For certain projects the size cost of Flex is too expensive (it happens!).
I like to prototype in Flex and then rip it out and replace my views with custom components when the application is near completion. PureMVC makes this really easy to do with it's Mediator pattern. I'm not sure there is any other framework that would allow me this workflow.
Personally, I think PureMVC went too far with it's portability goals: I enjoy that fact that it works with Flash AND Flex (for the reasons mentioned above), but feel that it should have stopped there, and made use of the native Flash Player event architecture.
Are there examples of people using PureMVC to build and port applications across multiple platforms?
My company is building a Flex application that we may need to port to other platforms:
Silverlight (likely)
Mobile (maybe)
Desktop (maybe -- not just AIR!)
TV sets (maybe eventually)
I am considering PureMVC as a framework if it can ease porting and maintenance. I am curious to know if other people have ported a PureMVC app to a different platform and what their experience was with porting and then having development proceed in parallel for the app on multiple platforms.
Cheers,
Karthik
PureMVC does not rely on a platform for its internal workings (Flash Events etc).
So, while it does not make porting any easier per-say, it can assist simply by showing us its friendly and familiar face wherever we may choose to go ;-)