Is it possible to access the properties of objects in xCode console?
If I try the following I get an error that he property doesn't exist.
po someObject.someprop
If I don't breakpoint the code and run the app it works fine so I know someObject.someprop exists. I don't think I have the grasp on xCode console yet? What I loved about Flex/Flash development is that I could set a break point and in the console window or variables view I could traverse every structure down to the ends of the earth.
I could see SomeDicionary[key].someArray[1].someObject.prop and it would show me the value. Is this not possible in xCode console or is there a trick to get to it?
You'll actually have to use the bracket syntax notation:
po [someObject someprop]
The debugger is sometimes very finnicky about syntax. This is filled with all sorts of helpful tips for debugging in XCode.
Just a side note, variables/properties declared in the implementation file (*.m) instead of the header file (*.h) can sometimes be invisible to the debugger variable list display depending on if the breakpoint is in that class's code, because of scope. Not necessarily required here, but useful to know seeing as how it is kind of relevant.
Related
I can't see object variables in Xcode debugger. I haven't changed anything in Build Setting. This happend to me after Xcode update and I can only print description.
Here is a screenshot displaying what I mean:
And this is what should by displayed in object:
Most likely the variable is outside the current scope. Current scope being the scope where the debugger is currently stopped.
So calling a method on the pointer to the object (which is what happens when the description is printed) will work, as you can access any memory, but the variable view might be limited to only the current scope.
It was probably bug in Xcode. With new version of Xcode it is working properly. Thank you everyone for answering
I have a method on one of my ViewController's that is called by one of its view's and delivered some value. It then sends out a message to a manager object with some information about the VC's state.
- (void)elementXChangedWithValue:(float)value {
ParameterManager * pMan = [ParameterManager sharedInstance];
[pMan updateParameter:self.elementX.parameter value:value];
}
In debugging, it was important for me to inspect what the .SomeElement.parameter state was so I could know what was getting lost in translation by the time I get to my ParameterManager.
Unfortunately, although Self is definitely non-nil and accessible the debugger shows scant information about the class making quick and practical glancing of the value difficult. (i will sometimes invoke "po" command in the debugger command line, however).
Not sure if it helps but this project is running heavy with the Objective-C/Swift interoperability although the ViewController is a fully Objective-C class.
Here is an image of what I am getting in the debugger. The drop-down arrow shows nothing but empty.
The debugger isn't perfect and sometimes you just cant see what is in certain areas, such as self. What does always work is NSLog's placed in code though, so if all else fails, add one of those in at the right place to print out the object you wish to know about.
The debugger may show more info after you make it execute these commands:
expr #import UIKit;
expr #import Foundation;
This loads the whole UIKit and Foundation symbols in the debugger at runtime, you only need to execute it once per debug session.
You can automate this with a user-defined breakpoint that'll be triggered every time your application starts in the debugger.
Source : http://furbo.org/2015/05/11/an-import-ant-change-in-xcode/
The strengthbar in my game doesn't work well after playing at least once of the level. So I wrote a method using CCLog to log out some variables and call this method in update: method. And I also set a breakpoint, when this problem appears it gets into debug mode of Xcode, then I use print to check the variables. However it appears that the values are different between using CCLog and using print command. Here's a screenshot that explains everything.
Here is my screenshot:
Does it have something to do with Multithreads(which I know nothing about)? I've checked the declaration of each logged variables, to make sure they're not declared several times using the same name.
OK, problem is solved.
When I wrote some delegate I used "Strong" which causes some retain cycles. Now I changed them all to Weak, and also changed the deployment settings to iOS 5 (or above).
The reason that the values of the variable are different is because in CCLog, the value belongs to the new scene, however there're more than one scene at the same time receiving my touches because of the retain cycles. Nothing wrong about XCode or Cocos2d, or CCBReader :-p
Hope this answer would help others. And many thanks to #Cy-4AH.
Because it was changed after it was printed. In the breakpoint you are lookng at new value.
I am working on trying to make a splitview based application. I am trying to use Apple's MultipleDetailView example code
http://developer.apple.com/library/ios/#samplecode/MultipleDetailViews/Introduction/Intro.html
I have never really used example code like this (I usually just atart from scratch). All i did was copy the code into the correct classes of my app, but when I try to run it on the simulator the app doesn't open.
I feel like I am maybe forgetting something obvious, since I didn't code it myself.
Thanks!
The usual debugging technique applies. Put a breakpoint somewhere early in the program -- the first line of main() for instance, and debug from there. Do you hit the breakpoint? If yes, move forward through the code until you find the line that causes the problem. If no, try to back up even further if you can, and also look for any clues as to what's going wrong. If the app is running at all, there should be some sort of error message in the console output.
"...the app doesn't open" doesn't tell us nearly enough to help you. Something like "the app delegate is instantiated, but it's window and splitViewController properties are nil" goes much further toward getting to the root of the problem.
I'm trying to use a recent feature of the Scintilla component, which provides OSX-like text-highlighting effect (the yellow animated bouncing box), and I'm stuck with an error that pops up intermittently :
EXC_BAD_ACCESS
pointing to this particular line :
if (layerFindIndicator!=nil)
if ([layerFindIndicator animationForKey:#"animateFound"])
[layerFindIndicator removeAnimationForKey:#"animateFound"];
(the ifs are mine; just in case I caught the object layerFindIndicator being nil, or deallocated or whatever... Unfortunately, it doesn't help...)
layerFindIndicator is seemingly a subclass of CAGradientLayer. (You may see the full code for layerFindIndicator, here).
Since, I'm an absolute newbie to Quartz Core, could please give me any hint as to HOW this could be debugged?
Since, I'm an absolute newbie to Quartz Core, could please give me any hint as to HOW this could be debugged?
This doesn't have anything to do with QuartzCore specifically (at least, I hope not)—it's general this-object-has-been-killed-before-its-time-how-do-I-find-the-killer stuff.
In Xcode:
Edit your current scheme.
For the Profile action, set it to use the Debug build configuration.
Dismiss that and then hit the Profile command.
Xcode will build for that action and then launch Instruments.
Instruments will prompt you to choose a template; you want the Zombies template. Once you've chosen it, Instruments will create a trace document and run your application. Switch to your application (if it isn't already frontmost), then do whatever causes the crash.
If the crash really is a dead-object crash, Zombies will reveal it. You'll get a flag in Instruments's timeline saying something like “message sent to zombie object 0xd3c2b1a0”, and your program will probably exit shortly thereafter.
In that flag is a tiny little button that looks like this: ➲ except it'll be gray. Click on it.
That takes you to the history of that object (actually of that address, including any previous objects or other allocations that have started at that address). Show your Extended Detail Pane (the one that appears on the right showing a stack trace), then scroll down to the end and then move backward (upward) step by step through time, looking at releases and autoreleases, looking for the one that isn't balancing out the object's allocation or a retain.
The solution will probably involve one or more of:
Changing a property to be strong or weak rather than assign/unsafe_unretained
Adding a property where you previously did not strongly own an object
Rearchitecting some things, if it's not clear which of the above you need to do or if either one of them seems like a filthy hack
Switching to ARC to get weak properties and __weak instance variables (both of which get set to nil automatically when the referenced object dies) and to get local variables being implicitly initialized to nil
But it'll depend on what you find in Instruments. And, of course, there's the chance that your problem—the bad access—isn't a dead object at all and all of the above will not help you.
Try this:
if (layerFindIndicator!=nil){
if ([layerFindIndicator animationForKey:#"animateFound"]){
[layerFindIndicator removeAnimationForKey:#"animateFound"];
}
}
Also check to see if it is released else were.
EDIT:
Another thing I found was you didn't have an white space in the if. Your code should now look like this:
if (layerFindIndicator != nil){
if ([layerFindIndicator animationForKey:#"animateFound"]){
[layerFindIndicator removeAnimationForKey:#"animateFound"];
}
}