In my cocoa application, i am uploading files to my server. And i have status bar to display the current status of file uploads. When i click on the status bar, it will show the status of current uploading file. For displaying the current status, i am adding retrieved value as objects to array.
Here i given the code for adding objects to array.
if(temp1 != Nil)
{
[printComplete addObject:temp1];
}
Same type of code has been used in my code at multiple points. But sometime i am getting the below error even after checking the nil:
-[__NSArrayM insertObject:atIndex:]: object cannot be nil
I can't get this error when i run this code from Xcode / at debugging stage. It occurs rarely when i run this as app. Can anyone provide the solution to resolve this issue.
Ok, so my original suggestion was to try the following, as OP was is testing for equality with Nil instead of nil:
if (temp1) {
[printComplete addObject:temp1];
}
Check out NSHiptser's take on nil/Nil.
However, it turns out that they are actually defined as the same thing, so this wouldn't be the source of the problem.
I would still recommend (stylistically) using each for their intended use.
Here's another interesting answer on the subject: https://stackoverflow.com/a/1843034/1716763
I'll leave this answer here, unless people think it isn't necessary.
Related
I broke something in my Pharo image, but i don't know exactly what. Now when I try to file-out my package to insert in a new image, I only see 'Why you see this menu' and 'Debug'. If I run menu debug in the playground, I get a FallbackMenu.
How can I fix this error?
EDIT: When I try to click on my package, The system browser is acting very weird an the following error pops up: link
Using Max's your code, i get 2 nil keys:
The first one is a mistake in my code (I assigned a class binding to nil instead of a instance variable with the same name). But I can't edit this because I can't access it through the System Browser.
The second one is ActiveEvent. I don't know where this comes from and whether this or the previous nil causes the System Browser to act weird
One possibility is that you nilled a class binding. Inspect the following to get a list of keys and values that are nil:
Smalltalk globals associations select: [ :assoc |
assoc value isNil or: [
assoc key isNil ] ].
BTW: rather then attaching a screen shot it would help if you attached the stack. To get the stack trace, right click on the topmost entry in the stack list (the one that's selected in your screen shot) and select "Copy to clipboard". Then paste the contents (or at least the first 30 frames) here.
Update
ActiveEvent seems normal. I have the same. The second one is very likely problematic. You may be able to cheat your way out by removing the entry:
Smalltalk globals removeKey: nil.
If done a quick try and it seems to work.
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"];
}
}
I have written this trivial action method associated to a textfield.
Every time I enter text into a textfield a search in a PDF is performed and PDFView automatically scroll to selection:
- (IBAction) search:(id)id
{
NSString *query = [self.searchView stringValue]; // get from textfield
selection = [document findString: query fromSelection:NULL withOptions:NSCaseInsensitiveSearch];
if (selection != nil)
{
[self.pdfView setCurrentSelection:selection];
[self.pdfView scrollSelectionToVisible:self.searchView];
}
}
Problem is that after 3 or 4 searches I get EXC_BAD_ACCESS on row (i).
If I debug I see that query contains an NSCFString and not an NSString.
I think it is a memory management problem..but where?
I replicated the same issue inside a trivial testcase:
#interface PDFRef_protoTests : SenTestCase {
#private
PDFDocument *document;
}
........
- (void)setUp
{
[super setUp];
document = [[PDFDocument alloc] initWithURL: #"a local url ..."];
}
- (void)test_exc_bad_access_in_pdfdocument
{
for (int i =0 ;i<100; i++)
{
NSString *temp;
if (i % 2 == 0) temp = #"home";
else if (i % 3 ==0) temp = #"cocoa";
else temp=#"apple";
PDFSelection *selection = [document findString: temp
fromSelection:nil
withOptions:NSCaseInsensitiveSearch];
NSLog(#"Find=%#, iteration=%d", selection, i);
}
}
Update:
1) It seems that it happens also if I use asynchronous search (method beginFindString: withOptions) every time I perform second search.
2) I found a similar problem to mine in MacRuby Issue Tracking: http://www.macruby.org/trac/ticket/1029
3) It seems that if I disable temporarily garbage collection it works but memory goes up.
I wrote something like:
[[NSGarbageCollector defaultCollector] disable];
[[NSGarbageCollector defaultCollector] enable];
surrounding search code
Another Update
Very weird thing is that sometimes all works. Than I clean and Rebuild and problem arises again. From a certain point of view is is not 100% reproducible. I suspect a bug in PDFKit or some compiler setting I have to do
Update Again
Dears it seems very crazy. I'd concentrate on testcase which is very trivial and which replicates easily the problem. What's wrong with it? This testcase works only if I disable (by code or by project setting) GC
Another Update
Boys it seems a bug but I downloaded an example called PDFLinker from Apple website (http://developer.apple.com/library/mac/#samplecode/PDFKitLinker2/Introduction/Intro.html#//apple_ref/doc/uid/DTS10003594). This example implements a PDFViewer. Code of my app and this example are quite similars. For the same search action on same PDF, my memory rises at 300/400 MB while PDFLinker rises at 190MB. Clearly there is something wrong in my code. But I am comparing it bit by bit and I don't think I am inserting memory leaks (and Instrument doesn't give me any evidence). Maybe is there some project-wide setting ?
Update Yet
Changing from 64 bit to 32 bit memory consumption lowered. Surely there is a problem with 64bit and PDFKit. BTW still EXC_BAD_ACCESS on second search
SOLUTION
Crucial point is that PDFKit with Garbage collection is bugged.
If I disable GC all works correctly.
I had another issue that had complicated my analysis: I disabled GC on Project Setting but GC remained enabled on Target Settings. So Apple's example PDFLinked2 worked while mine not.
I agree you have found a bug in PDFKit.
I got various forms of errors (segmentation fault, selector not understood, etc) running your test case. Wrapping the code in #try/#catch doesn't prevent all errors associated with this method.
I also got errors printing the log message.
To work around the bug(s), I suggest you disable GC during your invocation of -findString:fromSelection:, as you've already discovered.
Also, be sure to make copies of the values of interest from selection before re-enabling GC. Don't just copy selection either.
If you conduct searches from multiple places in your code I also suggest you extract a separate method to perform the search. Then you can invoke that one to conduct the searches for you without duplicating the GC disable/enable nesting.
This sort of thing is usually evidence that you're hanging onto a pointer to an object that has been destroyed. Turn on zombie objects (with NSZombieEnabled) to see exactly where and when you're accessing a bad object.
Judging from your screen shot it doesn't seem like you have NSZombie turned on. Probably the reason why it doesn't help you. Here's how you turn it on:
How to enable NSZombie in Xcode?
The screenshot you provided was otherwise very useful, but you really need NSZombie to figure out this kind of errors. Well, unless it's obvious, which it isn't from the code you posted.
EDIT: I read the comment that you're using garbage collection. I'm an iOS developer, so I have very limited experience with garbage collection in Objective-C, but as far as I understand NSZombie doesn't work in a garbage collected environment.
I'm not sure it should be possible to get EXC_BAD_ACCESS in a garbage collected environment, unless you create your own pointer and try to call methods on it without having created an object and I don't see why you would do that.
I've heard that some frameworks doesn't work well with garbage collection, but I wouldn't think PDFKit was among them. Anyway, the solution might be to not use garbage collection. Perhaps you should file a bug report with Apple.
keep PDFSelection *selection as a member variable and pass it in fromSelection: instead of nil.
It is possible that PDFDocument keeps the returned PDFSelection instance to improve the performance.
Did you try retaining the searchview stringvalue object before using it?
As you say it happens when you type fast and it happens for async calls, it is possible that the object stringValue is pointing to is being released between the time your query object is pointing to it, and the time you use it int the search.
You could try something like this to see if the problem persists:
- (IBAction) search:(id)id
{
NSString *query = [[self.searchView stringValue] retain]; // get from textfield
selection = [document findString: query fromSelection:NULL withOptions:NSCaseInsensitiveSearch];
if (selection != nil)
{
[self.pdfView setCurrentSelection:selection];
[self.pdfView scrollSelectionToVisible:self.searchView];
}
[query release];
}
Of course there is also the possibility that document is relased. How do you declare it? is it a property with retain? Can it be released by the time you are searching?
EDIT:
I see that you posted the code with the second parameter as NULL, but in your screenshot, this value is nil.
The documentation says you should use NULL when you want to start the search from the beginning.
http://developer.apple.com/library/mac/#documentation/GraphicsImaging/Reference/QuartzFramework/Classes/PDFDocument_Class/Reference/Reference.html#//apple_ref/doc/uid/TP40003873-RH2-DontLinkElementID_1
And as the compiler interprets nil and NULL differently, this could be leading to some weird behavior internally.
I'm getting an exception saying that the image cannot be nil on this line:
CCLabelBMFont *label = [CCLabelBMFont labelWithString:#"5" fntFile:#"weaponnumbers.fnt"];
What am I doing wrong? Am I supposed to specify the PNG somewhere different? I have it at the root of the project.
-(CCTexture2D*) addImage: (NSString*) path
{
NSAssert(path != nil, #"TextureCache: fileimage MUST not be nill");
Is weaponnumbers.fnt included in your target? E.g. is it compiled into the project?
Also, I think it's unlikely you're getting an exception here - you're probably getting an exception somewhere inside one of the calls made by this call. Try breakpointing the line before, and using the "Step In" breakpoint tool to step through the call stack and find the true nature of the exception.
I find Cocos2D exceptions to be pretty self-explanatory, when you can eventually get down to the right level of where the exception is actually being thrown.
A delete add and clean fixed it.
NSString stringWithContentsOfFile failing with what seems to be the wrong error code
I have a UITablView with search box, when you type a text, content will show according starting character typed in serach box then when you select uitableview cell, it goes to another page, which has nearly 30 objects like, UILabel and UITextView. This is the way I constructed the page. When I select a company, I get a memory warning: "Did recieve memory warning level 1".
I verified every object, I had given release statement. Still I am getting the problem. How should I avoid the problem?
For starter, launch your application with Instruments using the memory leaks template. This probably can tells you what objects are stay in the memory.
in xcode 5 just go to product -> analyse ... then see the list of the memory leaks break point... just go throw the break point and try to release those are not required variable and class object ....
some bref
Or
This tool tells you what library is leaking, then you can debug your code as you deem suitable. If it is well organized, you will be able to see immediately what object is leaking and fix the problem with ease.