I'd like to be able to Alt-Click an instance variable (or a method) as part of the program i created and read what it's purpose is.
The fact that Xcode is telling me the class variable is declared at - is nice but not enough. In this case i'd like to see custom text i typed to describe what an asset really is. Additionally type of the ivar would also be useful to know.
How can this be done? In this case, i wonder what exactly did i mean by assets
I specifically wonder if this information can be viewed from inside Xcode, similar to how Eclipse shows JavaDoc content.
You would need to create a documentation set for your project and install it in Xcode. appledoc can help you with this. This is a command-line tool that can generate documentation in Apple's style from specially formatted comments in your headers. You can also integrate this into your build process with a run script build phase, so that documentation is always up-to-date.
For small projects, it's usually not worth the effort though and you're probably better off just adding comments to your header files and jumping there with Cmd-click (Ctrl+Cmd+left-arrow to go back to where you came from).
You'll probably want to take a look at Apple's documentation on Documentation Sets as well as their article on generating doc sets using Doxygen. The latter is based on Xcode 3.x, so how relevant it is is somewhat questionable, but it'd be a good idea to take a look nonetheless.
That said, if you decide to use Doxygen (alternatives like HeaderDoc can be used for documentation, but I'm not sure what's available to you as far as creating doc sets goes), it looks like the main point is you'll want to throw GENERATE_DOCSET=YES into your Doxyfile (or whatever you decide to call it). After that, you'd just throw the results into ~/Library/Developer/Shared/Documentation/DocSets (according to Doxygen's documentation). I don't know whether this works in Xcode 4.x - it's worth a shot though, and it'd be nice to hear back on it.
Note: most of this was based on this answer by Barry Wark. Figure credit is due there, since I wouldn't have bothered looking into this were it not for his answer.
After a search here on the forum I found a question like that, and it redirected me to a tutorial which gave em some basic instructions on manipulating SpringBoard with CapitainHook.
To start I'd like to do it with normal %hooks only. Any hint where I could start?
This little introduction is meant for whoever has a minimal knowledge on Objective-C and knows what he is doing.
NOTE: I will refer to the theos install path as $THEOS. This could be ~/theos, /var/theos, /usr/theos... Yeah.
The most popular way of creating MobileSubstrate extensions, also known as tweaks, is using Dustin Howett's theos build suite. Details follow:
What is theos?
So, we should start with what theos is not:
The Operating System
A Greek God
A compiler
And of course, what theos doesn't do:
Teaches you how to code.
Creates tweaks without having you to think
Sets up a whole building environment and/or installs the iOS SDK.
Theos is a cross-platform suite of development tools for managing, developing, and deploying iOS software without the use of Xcode, featuring:
A robust build system driven by GNU Make, which makes its Makefiles easily deployable through everywhere with theos installed too.
NIC, a project templating system which creates ready-to-build empty projects for varying purposes.
Logos, a built-in preprocessor-based library of directives designed to make MobileSubstrate extension development easy and with optimal code generation.
Automated packaging: Theos is capable of directly creating DEB packages for distribution in Cydia, the most popular mean of package distribution in the jailbreak scene.
How to install theos?
On OSX: Have the iOS SDK installed and follow these instructions.
On iOS: Install the BigBoss Recommended Tools package from Cydia and run installtheos3.
On Linux: Find a mean to have the toolchain installed, and follow these instructions.
On Windows: Nothing is impossible, but if you actually manage to do so, please let me know. :P
How to use theos?
This is a very asked question and too vague. Since theos is a whole suite of development tools, it doesn't make sense to ask How to use it, but more specifically, to ask How to create software using theos.
First of all, always have the Theos Makefile Reference in hand. It covers the basics of creating a theos Makefile, and that includes solving your linking issues adding a framework or private framework to the project.
Now, you can either create your own Makefile from scratch, create your little theos clone/symlink and start coding, but theos makes this step easier. You can just use nic.pl.
A very simple example of running NIC to create something can be found here. It's very straight-forward and sets you up right-away for programming.
Now, here's where we start getting back to topic.
Creating a tweak with theos
First of all, do not run NIC when inside $THEOS/bin. NIC will create the project directory exactly where you're running it from, and it avoids any project being created in $THEOS/bin. Therefore, you'll end up with a simple error which can be avoided by creating the project directory somewhere decent.
Run $THEOS/bin/nic.pl and choose the iphone/tweak template. You will be prompted by simple information which you may well know well how to answer, except for the last field: MobileSubstrate bundle filter.
Since a big part of MobileSubstrate is not just the hooker (the library which switches original methods/functions with yours), but also the loader (the part which gets your hooking to be inserted into certain processes), you have to supply this basic information for the Loader to know where to load your tweak. This field is but the bundle identifier for the application where this project will be inserted.
com.apple.springboard, the default option is the bundle identifier for SpringBoard, the application which is:
The iOS Homescreen
The launcher/displayer of common applications
The iOS Status Bar
Handler of some high-level essential background processes
Therefore, there's where many tweaks take place, altering behavior from something as trivial as app launching to something like how the whole homescreen UI looks like.
Programming a tweak with Logos
Now, the directory generated by NIC will contain:
The Theos Makefile, where you'll change information related to compiling
The control file, where you'll change packaging-related information
A symbolic link (or shortcut) to $THEOS named theos/
The main code file, defaulted as Tweak.xm. It is already added to the Makefile for compiling, so you can start coding right-away with it!
On knowing what to do
Now, you don't have SpringBoard's source code laying around, and you can't guess what methods to hook from nowhere. Therefore, you need a SpringBoard header set. For that, you need to use a tool named class-dump-z and run it into the SpringBoard binary (which is inside the iOS filesystem) to obtain header files including all class declarations and its methods inside the application.
From that (a deal of guessing and logging a method call is involved) you can start messing around with what you want in a tweak.
Of course, if you are not hooking SpringBoard you can use class-dump-z as you would in other binaries, such as UIKit, MobileSafari, etc.
Note that for when reversing App Store apps, they'll be encrypted. You'll need to decrypt those (I am unfortunately not allowed to tell you how-to), and then just run class-dump-z on them.
On obtaining private headers
Stuff like preference bundles require the headers for private frameworks, in that case the Preferences framework's headers. Else you'll get endless missing declaration errors (as I guess you could assume).
Getting them has the same logic applied the previous step. Run class-dump-z on, at this case, the Preferences binary and throw the headers at your INCLUDEPATH. The INCLUDEPATH is where the compiler will go looking for headers you include like #include <stdio.h>. Yes, stdio.h is inside one of the directories which build a compiler's INCLUDEPATH!
When compiling with a theos Makefile, $THEOS/include counts as part of your INCLUDEPATH, which means, you can just throw your dumped headers over there and include them later.
(Note that class-dumped headers aren't always perfect, so you're likely to have a couple of header-related compilation errors which can be easily fixed with something like removing a #import directive or changing it, or adding a couple of declarations.)
Code tips
You can't link against SpringBoard, so whenever you require a class from SpringBoard you have to use either the Logos %c directive or the objc_getClass function, as defined at <objc/runtime.h> to get it. Example: [%c(SBUIController) sharedInstance], [objc_getClass("SBUIController") sharedInstance].
When not knowing what a method does or how something works in SpringBoard, try disassembling it with IDA or others. I use IDA Demo (<- noob!) for my disassembling.
Looking at example code is amazingly helpful for both learning and figuring out how something works inside SpringBoard or others (again..). Great people at GitHub to have a projects looked at are rpetrich, chpwn, DHowett, EvilPenguin, and of course way more.
To also find about how SpringBoard and other works (...), have a look at a class's article at the iPhone Dev Wiki!
Epilogue
Wait, where's the good part? Where do I learn about coding in Tweak.xm?
Well, the original question was actually How to start MobileSubstrate tweaks programming?. You're all setup, hopefully with all headers placed, ready to type in make and see your project magically compiled with theos.
All you need to do is now to actually dig into your headers or your disassembly and go hooking, calling, etc.!
Logos Reference contains exactly how to hook and use other features of Logos, and the MobileSubstrate article on the devwiki is also a great read.
In case there is any doubt, don't hesitate joining the irc.saurik.com #theos IRC channel. It's a great way to discuss theos-related topics and ask questions. I'm mostly there, along with other greatly smart people ;)
You are looking for Theos created by DHowett.. Theos allows you to make tweaks, but it doesn't give you everything you need. You don't get every header for iOS, so you have to class-dump-z the frameworks/private-frameworks from the iOS SDK. Get started here: http://iphonedevwiki.net/index.php/Theos/Getting_Started, or join irc.saurik.net #theos for more help. You can also look at my projects that use theos: https://github.com/evilpenguin
You sound like you're looking for theos. Take a look at this, it should help get you started.
I'm new to Mac programming. When I open sample projects, I often get 'deprecated' code warnings during a build. I'd like to fix these and get a clean build using XCode 4.
When Apple deprecates something, how do I find out why it was deprecated?
More importantly, how do I find out what is the 'new' correct way to implement the deprecated task?
For example, I'm seeing deprecation warnings for: QTMovieSizeDidChangeNotification, writeWithBackupToFile, documentForFileName, shouldCreateUI, setShowPanels, QTMovieCurrentSizeAttribute, and many others.
Look up the method in the documentation - they show the deprecated methods and tell you what the preferred methods are.
For example writeWithBackupToFile is clearly marked as deprecated and shows that writeSafelyToURL:ofType:forSaveOperation:error: should be used instead.
Same with shouldCreateUI which shows that either openUntitledDocumentAndDisplay:error: or openDocumentWithContentsOfURL:display:error: should be used instead.
Also, read the other methods in the documentation - you'll find things that do what you need. For example you list QTMovieSizeDidChangeNotification as being deprecated (in QuickTime 7.6.3). Right above it in the documentation you can see QTMovieNaturalSizeDidChangeNotification which has been available since QuickTime 7.6.3). Use that instead.
Look for the deprecated things in the documentation. Usually, there's a note that suggests what to use instead.
For example, the documentation for writeWithBackupToFile:ofType:saveOperation: says:
This method is called by action methods to save document contents to a file. (Deprecated in Mac OS X v10.4. Use writeSafelyToURL:ofType:forSaveOperation:error: instead.)
Search the documentation for that method/function/constant. It should list there what to use instead, or at least bring up a class that obviously has other methods that do something similar.
I know this is pretty much a stupid question. I know almost nothing about how compiler really works.
But recently I want find what symbol name does the compiler generate for my ivar, my methods.
Where and how can I know the answer? (I have only used some IDEs. So if the solution is better to be simple . And it would be great help if the instructions you provide is really explicit)
(By the way,is there any reference that i can learn about the things like this?)
PS.I'm IOS developer.And if gcc and LLVM works different answer on this question , I would like to know both.
You can use nm to dump the content of a binary object. Then, each compiler has its own way of mangling. I suggest you have a look at Name mangling for objective C in wikipedia, it will help you understand how mangling works.
Surely GCC and Clang must have compatible name-mangling schemes, since they can use each other's code.
If you are using XCode 3 select a source file and then pick "Show Assembly Code" from the Build menu.
Apparently XCode 4 users do not need assembly code :-(
Very, very new at Obj-C... that said, I had some problems with code earlier, which seem to be resolved (I guess!). Now, when I do a build, I get this:
I am not using vanilla SQLite, but rather SQLCipher, (http://sqlcipher.net)
What symbols is it talking about? and how do I fix it?
Thank you (in advance) for looking at this... I'm "dead in the water" until I can get this fixed!
It looks like you haven't added the SQLite library to your project. Choose Project->Add to Project... and select the library.
When Xcode says 'symbols not found,' it's telling you that you're using a name for something that's not defined anywhere. The specific symbol it shows you is _sqlite3_open, which looks like the sort of thing that would be defined by the SQLite library.