Does anyone know how programs like iPhoneExplorer manage to list/add/remove files on an iDevice?
I would like to do something similar (but more basic) in a Cocoa Touch application.
It's technically not an Apple-approved™ method, so don't plan on putting this in the App Store. But it is possible. First, import the MobileDevice framework from /System/Library/PrivateFrameworks. Then use the reverse-engineered header for the MobileDevice framework:
http://code.google.com/p/ziphone/source/browse/trunk/ZiPhone/MobileDevice.h
It includes all the methods necessary to communicate with an attached iOS device.
There's also a C++ wrapper for it that's a bit easier to use, especially for detecting the device in the first place. It also includes methods specifically for jailbreaking, but they're not required.
http://code.google.com/p/independence/source/browse/trunk/libPhoneInteraction/PhoneInteraction.cpp?r=323
Related
This question pops up quite often here, even if just implicitly when users mistag their iOS questions. So, what’s the difference between Xcode, Objective-C and Cocoa?
Objective-C is a programming language. It could be said that it’s just a description of what valid Objective-C programs look like and what they mean. If you have a source code listing written in Objective-C, you need an interpreter or a compiler to put the listing to work. Languages like Objective-C are usually compiled, so most people use a compiler (like LLVM). Objective-C is almost exclusively used to develop for iOS and OS X, but there are other uses, too – as an example, some people write Objective-C for Linux.
You can use a text editor to write the sources and a compiler to turn them into an actual programs, but with modern technologies there’s much more to take care of, so that there is another program to make your job easier. These are called Integrated Development Environments, or IDEs. An IDE offers you a convenient way to edit the sources, compile them, debug the resulting programs, read the documentation, and many other things. Xcode is one such IDE. An important observation here is that Xcode does not compile your sources itself, it just calls the standalone compiler (LLVM). And Xcode is not the only IDE you can use to develop Objective-C apps – there’s AppCode, for example.
Writing iOS or OS X apps from scratch each time would be very time-consuming. That’s why Apple provides the developers with a good set of libraries. The libraries are simply a huge amount of source code written by Apple, and this source code takes care of most things that apps have in common. These libraries are called Cocoa.
Now, if you can’t figure out how to extend a class, you are most probably talking about Objective-C. It doesn’t have anything to do with Xcode or Cocoa, you could be very well writing some GNUstep code for Linux using Vim as an IDE and GCC as a compiler. On the other hand, if your Xcode build process fails because of some mysterious setting, or if you’re trying to build a static library in Xcode, that’s clearly an Xcode issue. And if you can’t figure out how to use some NSObject facility or the NSFileManager class, that’s Cocoa. (But it doesn’t have to be Xcode-related, as you could use AppCode or TextMate as your IDE!)
Originally available on my blog. Feel free to link to the blog post or this question when retagging or explaining the difference.
Xcode is the integrated development environment (IDE)—the application—that developers use to write software for iOS and/or OS X. It includes the editor, the build system (determining what to build to produce the desired target), and quite a few other things.
Objective-C is the main language that developers write such software in. They may write bits of it in pure C, use C++ or combine it with Objective-C (producing Objective-C++), or write some or all of the program in another language entirely, such as MacRuby, Java (with j2objc), or C# (with MonoTouch).
Xcode includes the Clang compiler, which turns code written in Objective-C, C, and a few other languages into executable code. Most error messages come from Clang, and Xcode relies heavily on it for search indexing, syntax highlighting, and name completion of Objective-C code.
Cocoa and Cocoa Touch are application frameworks. Each one is a suite of many individual frameworks (libraries stored in folders named blahblah.framework), such as:
Foundation (both): General object-oriented utilities, including NSString, NSURL, NSFileManager, etc.
Core Foundation (both): Mostly the same thing, but different, mainly in having a C-based API rather than Objective-C
Application Kit (Mac): Application and windowing framework
UIKit (iOS): Application and windowing framework
Core Graphics (both): Drawing
Core Animation (both): Sprite-management and animation framework
(and many, many more where they came from, especially on the Mac)
So:
You can use a framework besides Cocoa or Cocoa Touch, but you'll have to have some Cocoa/Cocoa Touch code, at some level, in order for your application to talk to the system, receive events, draw, etc. Frameworks that specifically target Mac and/or iOS will include the relevant wrappers for you, at varying levels of quality.
You can use a language besides Objective-C, but you'll have lots of syntactic awkwardness, as most of Cocoa and Cocoa Touch are designed for Objective-C's unique syntactic features (particularly selectors).
You can use an editor besides Xcode, and you can even use a build system besides Xcode (such as make), but Apple's App Stores expect apps built a particular way (especially with regard to code signing), so unless you're not targeting the App Stores, any other build system has to replicate what Xcode does or risk its users getting rejections.
A clear mistake is failing to differentiate Xcode from everything else. Xcode is the tool you are using to program in - to edit code, run code, etc. So if you are having trouble with the tool (e.g., the window doesn't show you your code properly, or you're having trouble drawing your interface, etc.), that's an Xcode problem.
If you don't understand why your code doesn't work, you're probably having an Objective-C problem or a Cocoa problem. But you won't necessarily know which.
It's an Objective-C problem if the root of your trouble is that you don't know how the language works (e.g. you don't know what the asterisk is for, or that declaration is not instantiation, or that messages to nil do not error out but don't do anything either).
It's a Cocoa problem if you don't grasp the delegate architecture or how a view controller works.
But my experience of the way people pose questions is that you may be ignorant of which of these you are ignorant of. I don't mean you personally, I mean all of us. This can make it difficult to pose the question properly because you don't know what exactly it is that you don't know — if you did, you'd know it and you probably wouldn't be having a problem (you'd be fixing the problem and on to the next thing).
I am writing a Mac OS X desktop application in which I want to be able to parse fragments of Objective-C such as variable and method declarations, as well as full Objective-C header and source files.
It looks to me as if I should be making use of Clang to do this, but I could do with some pointers and examples on how to integrate it as a library in my project, and how to invoke it to parse strings and files.
Can anyone provide me with any help on this?
You probably want libclang, code browsable at http://llvm.org/svn/llvm-project/cfe/trunk/tools/libclang/ (though you'll need to checkout the entire Clang repo to build it). There's very little documentation around on it, sadly. There is a presentation at http://llvm.org/devmtg/2010-11/Gregor-libclang.pdf that might help kickstart things, but mostly just some hunting through the code is the way to go.
Clang is actually more modular than libclang provides for (you can import just the components you want). If you've adventurous, there are examples at http://llvm.org/svn/llvm-project/cfe/trunk/examples/.
I'm about to write code for Windows that has somewhat similar functionality to the one existing in already written application for iPhone. I'm thinking of separating common functionality to form a component and compile it to both to iPhone and to Windows. This code is written in Objective C and uses RestKit and Core Data (and probably sqlite). Is compiling it for Windows a viable task? As I understand it GCC could compile Objective C on Windows but I'm unsure about the RestKit and Core Data api availability on Windows. I have seen two names that could be of use: GNUStep and Cocotron but I don't know if they will play well together with RestKit.
Note: I have no idea about iOS development so I might be confusing things. Any help is appreciated.
You will not easily be able to share this functionality between your applications. CoreData uses a custom opaque (not documented) format for the sql store. You would be hard pressed to reverse engineer this.
You will probably save a lot of time by rewriting that part for windows, rather than trying to get it working. There really isn't much iOS code that can be reused under windows, unless you have written pure C or C++.
I want to create an Objective-C application which lets you specify a class implementation at runtime.
I want the user to type some code (correctness of the code is out of scope for now).
When the user is done i want to create a class of the typed code and use it in the application.
So i want to dynamically add code in runtime of the application. Is this possible?
If so, how can i achieve this? If not, why not and are there any alternatives to create the same effect which i want to create?
Thanks.
You can dynamically load classes at runtime, but to get there you'd first need to handle distributing a compiler, its compilation dependencies (headers, ...), setup its enviroment, etc.
Usually applications use scripting languages that are painlessly embeddable (Lua, Python, ...) or already available on the platform (JavaScript, AppleScript, ...).
I'd check out F-Script. It's closer to smalltalk than Obj-C, but IMO it's closer to Obj-C than JavaScript or Lua :-)
On iOS devices, this isn't possible. On a Mac you could link against the clang+llvm libraries and use them to generate code into a buffer, then mprotect() the buffer to be executable, I believe.
For the application I am writing, I need to access some other applications' items, for which Applescript seems the best way to go. I have been using the Appscript framework, which worked well, because it allowed me to thread it and not make my app lock up when an Applescript was taking a while. However, now I am attempting to make my application 64 bit compatible, and it seems like the Appscript framework does not support 64 bit. Is there a "good" way to use Applescript in Cocoa that will not lock up my application, but still give me the full control I need?
--firen
It seems like SBApplication should work, but I haven't used it before.
According to #cocoadevcentral:
SBApplication: use to make cross-application scripting calls with Objective-C instead of AppleScript. Ex: get current iTunes track.
Here is is the excerpt from the documentation:
The SBApplication class provides a mechanism enabling an Objective-C program to send Apple events to a scriptable application and receive Apple events in response. It thereby makes it possible for that program to control the application and exchange data with it. Scripting Bridge works by bridging data types between Apple event descriptors and Cocoa objects.
Although SBApplication includes methods that manually send and process Apple events, you should never have to call these methods directly. Instead, subclasses of SBApplication implement application-specific methods that handle the sending of Apple events automatically.
For example, if you wanted to get the current iTunes track, you can simply use the currentTrack method of the dynamically defined subclass for the iTunes application—which handles the details of sending the Apple event for you—rather than figuring out the more complicated, low-level alternative:
[iTunes propertyWithCode:'pTrk'];
If you do need to send Apple events manually, consider using the NSAppleEventDescriptor class.
Hope that helps!
As Blaenk mentioned Scripting Bridge may well be the way to go, although it can prove somewhat inefficient if you have to iterating through large arrays etc.
The simplest way to run an Applescript in Cocoa is using NSAppleScript.
Apple has some pretty good examples, which I found useful when I needed to do something similar. There are three articles you might want to take a look at. They all contain some sample code, which I always find very useful.
A Few Examples of using Scripting Bridge
Performance & Optimisation with Scripting Bridge
NSAppleScript Technote/Example
I created a gist with the full URLs as I can't post more than one link, what with being a newbie and all.
http://gist.github.com/130146
it seems like the Appscript framework does not support 64 bit.
Should work. Make sure you set the correct architectures and SDK (64-bit requires 10.5) in the Xcode project. File a bug report if you have a specific problem.