I recently bought a Mac, and want to rewrite a few of my programs in Objective-C with Cocoa, but have no experience in either.
What I imagine would be the easiest to start with was some of my OpenGL code in C/C++ (just my classes, macros, and math functions mostly). I read somewhere C++ code can be used in Objective-C++ compilers. Is this true, and if so, how do I include the files?
Also, where can I find good resources on how to maybe start a basic application with Cocoa in Objective-C? The resources for Cocoa seem to be sparse compared to that of Windows and OpenGL, so I am having trouble finding information (free information mind you).
I would appreciate any help at all, also let me know if you think this conversion is a bad idea. Thanks in advance!
Why converting when you can import the C++ code as is? You just have to change your objective-C files that call C++ functionality from .m to .mm, please check the following link:
http://answers.oreilly.com/topic/631-how-to-get-c-and-objective-c-to-play-nicely-in-xcode/
Related
I'm building a cross-platform mobile application and I was suggested to use OF environment and compile my application using Xcode. I'm a Mac user and I started programming few time ago (so I'm really a beginner).
I need some class to get information about position and rotation so I was thinking to have a look at some SDK such as MoSync or CMDeviceMotion in order to understand which one is the most suitable to my purpose.
I also noted here:
https://developer.apple.com/library/ios/documentation/CoreMotion/Reference/CMDeviceMotion_Class/index.html#//apple_ref/doc/c_ref/CMDeviceMotion
that CMDeviceMotion is written for Obj-C and Swift.
So I have two question:
is it possible add to the main project libraries that are not part of OF?
should I use only C/C++ class?
Thanks.
I'm not sure if stackoverflow is the right place to ask a q like this, since any answer is very much prone to subjectivity.
I don't think there's a lot of valid reasons to even try to connect "MoSync" with OF, since they are both in a way "platforms" for developing apps, supporting different languages (javascript on the first and c++ on the latter). It is possible to mix objective-c (and swift) code with c++, so you can combine CMDeviceMotion with OF.
However to answer your question: It seems that if you want to have device information you don't need to go out of the scope of openFrameworks. Take a look at the "ofxIOSCoreLocation"class of OpenFrameworks/ofxIOS. It provides means for altitude, location, direction and so forth.
It is very possible to cross Objective-C and C++ with what is called Objective-C++ (by standard .mm instead of cpp), in openFrameworks.
Limitations and features: https://en.wikipedia.org/wiki/Objective-C#Objective-C.2B.2B
You can then from the Objective-C++ class (lets say for example ofApp.h), call Objective C delegates and functions directly.
You can not embed swift like this, however you there are some methods of using objective-c middle man class.
I've been learning C++ and SFML for quite a while now, and love the language and library, as it works well for me. I've gotten interested in making iPhone apps, which I realize uses Objective-C.
Anyway, my question is, is there a way for me to call the use of C++ code (with SFML) in Objective C. So while the program would work on an iPhone, the actual code is written mainly in C++?
Sorry if that's not.... descriptive enough, if you need more clarification, feel free to ask!
Thanks in advance!
Yes. In fact, you would probably use Objective-C++. Name your source files with the ".mm" extension instead of the ".m" extension, and the compiler will compile them as Objective-C++. There's even a Wikipedia article about it. You can also use regular C++ source files in your code and call them from Objective-C classes in this scenario. If you have more specific questions about it, feel free to ask.
I would like to create a portable library for iPhone, that also could be used for other platforms.
My question is the fallowing:
Does anyone knows what is the best to be used on the iPhone: Objective-C or Objective-C++? Does it works with C++ the same way as Objective-C with C or not?
Reasons: Objective-C is a superset of C, but Objective-C++ is not a superset of C++.
Thanks in advance!
UPDATE: What about memory usage, speed in the same implementation of an use case?
UPDATE1: If anyone can provide any more information, he'll be welcome.
If you're writing a portable library, and don't need specific language features for it, why not write it in straight C? It can be easily called from C++, C, Objective-C, and many, many other languages.
If you require specific language features that aren't available in C, you should tell us what they are so you can get better advice =)
I believe your information is incorrect. Objective-C++ is a superset of C++. Any C++ is legal Objective-C++. In addition, you can mix Objective-C and C++ code in an Objective-C++ (usually .mm) file and (with some restrictions) mix Objective-C and C++ class instance variables within an Objective-C++ class. Objective-C++ is particularly useful for interfacing between Objective-C and a C++ library. Write your cross-platform library in C++. You can then call it from Objective-C++ within an application. Re-read the Objective-C++ section of the Objective-C language guide for more info.
The major downside to using Objective-C++ is increased compile times (Objective-C++ is even worse than C++ and the Clang LLVM compiler doesn't handle Objective-C++ yet). There is no performance difference between Objective-C and Objective-C++ beyond any differences in the code that's called (e.g. if you're a better C++ dev., your C++ will probably be more efficient than your C library and visa versa).
They're not really different languages. Objective-C++ is just Objective-C with slightly limited support for including C++ code. Objective-C is the standard dialect, but if you need to work with C++, there's no reason not to use it. AFAIK, the biggest practical difference (aside from allowing use of different libraries) is that Objective-C++ seems to compile a bit slower. Just be sure to read up on it first if you do decide to go that route, because the merging of C++ and Objective-C is not 100% seamless.
If you are going to use this library on platforms other than the iPhone and Mac OS, you should use C++. If you plan only to port it to Mac OS, then go ahead and use Objective-C. Objective-C++ is just a way to integrate existing C++ code into Objective-C projects. Thus, you would not write a library in it. You might, however, use Objective-C++ to use this library from an iPhone or Mac project.
The truth is you can use C or C++ in Xcode. The reason to use Objective C for Cocoa and Cocoa Touch (iphone) is because of it's ease of use and how it handles many of the memory issues you would come across on it's own. Objective C and Xcode work like a dream. I would also recommend checking out http://www.kevincallahan.org/software/accessorizer.html
Accessorizer is amazing and cuts development time into nothing.
Having said that I see no problem in writing functions/methods in C or C++ and using them within a part of your XCode project. Just do not expect to use Objective C to play as nicely on other platforms. Apple and Windows development IDE's are different and Microsoft has a nice habit for not making things as compatible with other environments (not just Apple.)
I am glad to hear someone out their trying to reuse their code for other projects : ) Too many people forget to create their own libraries these days and I haven't the slightest idea why.
I hope this helps. Cheers,
Matthew
Here is your caveat: Spend the hundred on becoming a developer and launch xcode the IDE you will be working with on the Mac - this would be the best way for you to decide as it is apparent that you do not fully understand how this platform works at all.
Please don't be rude to everyone trying to help you. This community is built on respect. The people here really actually do help out and care and there are few places like this on the net left.
Go for C or C++ - I do not see any reason for recommending one over the other without knowing more about your goals.
In terms of memory usage, C++ and C do demand more disciplined coding. In terms of speed, C and C++ will in virtually any case be faster than any ObjC/ObjC++ solution. I do frequently mix my Objective C applications with C and C++ code and was always pleased with the results. As Jonathan correctly stated, ObjectiveC++ is mostly a bridge for using C++ code/libraries within your Objective C application/s.
You can freely use C++ objects from within Objective C++. You can however NOT use Objective C/C++ objects within C++. So its a one-way-road. To overcome any limitations imposed by this restriction, simply wrap your C++ objects with Objective C++ classes where needed.
"Objective-C is a strict superset of C, and Objective-C++ is a strict superset of C++." - https://developer.apple.com/library/mac/documentation/DeveloperTools/Conceptual/CppRuntimeEnv/Articles/SymbolVisibility.html
I'm writing a graphical application using Objective-C for the front end and C++ for the graphics processing and network communication. I read around on Apple's site looking for a way to link either a .dylib or .so with my C++ code in it to my Xcode project, but nothing seemed to work. I was able to get the project to reference it and link against it, but when I tried to call functions from that .dylib, it was saying that it didn't know what I was trying to do. Does anyone know what is going on here?
I know that Objective-C has all the libraries I would need to do graphics and networking, but I just feel like doing it like this. I haven't done much C++ in a while and I want to learn more Objective-C, so what better way than to use them together?
Thanks,
Robbie
Most of the projects I work on have an ObjC frontend and C++ backend. If you're dealing exclusively with functions, then Dave Gamble's name mangle fix is correct, but if you're dealing with more complex situations, where you need to deal with both ObjC and C++ objects, your best bet is to wrap the C++ objects in ObjC objects. Using opaque references (which is a very fancy way of saying void*), you can actually hand around C++ objects in ObjC and vice versa. I have some sample code that may be helpful.
That said, for graphics you're probably going to take a serious performance hit doing custom C++ rather than using Core Image and the related frameworks. Core Image and the other graphics frameworks are highly optimized for the Mac, and you're very unlikely to do better with hand-rolled C++ (or even very well-written C++ that isn't specifically for the Mac). As you move to 10.6 and grand central dispatch, the performance difference is going to be even more notable because you'll lose all the parallelization advances that you would get for free otherwise. This has nothing to do with ObjC; Core Image is C. You can call it from C++ all you like. I just recommend against custom graphics processing on Mac in any language unless you need portability or you have the expertise necessary to beat Core Image.
You're going to hit one obstacle in the form of what's called "name mangling". C++ stores function names in a way not compatible with Obj-C.
Objective-C doesn't implement classes in the same way as C++, so it's not going to like it.
One way around this is to implement a set of simple C functions which call the C++ functions. It'll be a good challenge to keep the number of C functions as low as possible! You'll end up with a nice compact interface! :)
To declare these functions in a C++ file, you'll need to mark them as C with:
extern "C" int function_name(char *blob,int number, double foo) {...}
This disables the standard name-mangling.
Build a header file with the prototypes for all these functions that you can share with your objective C code.
You won't be able to pass classes around in the same way (because your ObjC code can't use them), but you'll be able to pass pointers (although you might have to lie about the types a little).
I'm all for language diversity, but Objective C is insane. So I'm curious: is it possible to code iPhone apps with C++ while using the Cocoa API, etc?
Although Objective-C does indeed appear to be "insane" initially, I encourage you to stick with it. Once you have an "a-ha" moment, suddenly it all starts to make sense. For me it took about 2 weeks of focused Objective-C concentration to really understand the Cocoa frameworks, the language, and how it all fits together. But once I really "got" it, it was very very exciting.
It sounds cliché, but it's true. Stick it out.
Of course, if you're bringing in C++ libraries or existing C++ code, you can use those modules with Objective-C/Objective-C++.
Short answer, yes, sort of. You can use Objective-C++, which you can read about at Apple Developer Connection.
If you know C++ already, learning Objective-C would be pretty simple, if you decided to give that a try. More info on that topic is at the ADC as well.
I use Objective-C to slap the UI together.
But the hard guts of the code is still written in C++.
That is the main purpose of Objective-C the UI interface and handling the events.
And it works great for that purpose.
I still like C++ as the backend for the code though (but that's mainly becuase I like C++) you could quite easily use Objective-C for the backend of the application as well.
First off, saying Objective-C is "insane" is humorous- I have the Bjarne Stroustrup C++ book sitting by my side which clocks in at 1020 pages. Apple's PDF on Objective-C is 141.
If you want to use UIKit it will be very, very difficult for you to do anything in C++. Any serious iPhone app that conforms to Apple's UI will need it's UI portions to be written in Objective-C. Only if you're writing an OpenGL game can you stick almost entirely to C/C++.
Having some experience of this, you can indeed use C++ code for your "core" code, but you have to use objective-C for anything iPhone specific.
Don't try to force Objective-C to act like C++. At first it will seem to you this is possible, but the resulting code really won't work well with Cocoa, and you will get very confused as to what is going on. Take the time to learn properly, without any C++ around, how to build GUIs and iPhone applications, then link in your C++ base.
You have to use Objective C to interface with the Cocoa API, so there is no choice. Of course, you can use as much C++ as you like behind the scenes (Objective C++ makes this easy).
It is an insane language indeed, but it's also... kind of fun to use once you're a bit used to it. :-)
I'm not sure about C++, but you can definitely code iPhone applications in C#, using a product called MonoTouch.
You can see this post for detailed discussion on MonoTouch Vs Obj-C: How to decide between MonoTouch and Objective-C?
I'm in the process of porting a computation-intensive Android app written in Java to iOS6. I'm doing this by porting the non-UI parts from Java to C++, writing the (minimal) UI parts in Obj-C, and wrapping the former in a (small) C interface using the standard C/C++ technique, so that it can be accessed from Obj-C, which is after all a superset of C.
This has been effective so far, and I haven't encountered any gotchas. It seems to be a legitimate approach, since Xcode lets you create C++ classes as well as Obj-C classes, and some of the official sample code does things this way. I haven't had to go outside any officially supported interfaces to do this.
There wouldn't seem to be much to gain from writing my remaining UI code in C++ even if it were possible, in view of the help given to you by the interface builder in Xcode, so my answer would be that you can use C++ for almost all your app, or as much of it as you find appropriate/convenient.
Yes but Thinking that you can program every kind of program in a single language is a flawed idea unless you are writing very simple programs. Objective C is for Cocoa as C# is for .NET, Use the right tool for right job, Trying to make C++ interact to Cocoa via writing bridging code and trying to make C++ code behave according to Cocoa requirements is not a good idea neither expecting C++ performance from Objective C is. You should try to layout design and architecture of app keeping in view existing skills and determine which part should be written in which language then build accordingly.
I'm currently writing an Objective-C++ framework called Objective-X, wich makes PURE C++ iPHONE PROGRAMMING possible. You can do like this:
#import "ObjectiveX.h"
void GUIApplicationMain() {
GUIAlert Alert;
GUILabel Label;
GUIScreen MainScreen;
Alert.set_text(#"Just a lovely alert box!");
Alert.set_title(#"Hello!");
Alert.set_button(#"Okay");
Alert.show();
Label.set_text(#"Ciao!");
Label.set_position(100, 200, 120, 40);
MainScreen.init();
MainScreen.addGUIControl(Label.init());
}
and compile it using GCC's appropriate commandline options. I've already compiled this helloworld app&it w0rkX0rz like a charm. ;-) It'll available soon on GoogleCode. Search for Objective-X or visit http://infotronix.orgfree.com/objectivex approx. a week later!
Updated (but apparently inactive) URL: http://code.google.com/p/objectivex/
It may be a bit offtopic, but anyway. You can program c++ right on iOS devices. Check out CppCode ios app - http://cppcode.info. I believe it helps to learn c and c++ and objective-c later.