Ok so as far as i can tell I'm getting the error when I'm calling a setter designed to fit the view into it's correct box.
_parrentViewFrame = parrentViewFrame;
self.containerView.frame = _parrentViewFrame;
self.containerView.bounds = _parrentViewFrame;
[self.containerView layoutIfNeeded];
on the layoutIfNeeded i get this error
*** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[__NSCFNumber length]: unrecognized selector sent to instance 0xb000000000000343'
Now I've got similar code all over the app and it works just fine. I've put a symbolic break point at -[NSObject(NSObject) doesNotRecognizeSelector:]. but this doesn't really help. I still can't tell which object it's trying call length on. containerView is a simple UIView. The instance is always 0xb000000000000343, not sure if thats significant but it seems like it would be. How can I debug this problem?
One of two things might be going on:
As rmaddy pointed out, you may have assigned an NSNumber to a property that is not NSNumber. NSString seems like a likely candidate or an object that conforms to UILayoutSupport.
You might be overreleasing an object and an NSNumber is taking the place of that pointer, hence the bad selector call. If that is the case, you can turn on NSZombies, which will help you catch that overreleased object. Enable NSZombies in your scheme settings under Diagnostics.
Related
After I completed the tutorial: Start Developing iOS Apps Today
I got the same exception asked here: IOS Tutorial Exception (ToDo Sample)
and the app crashed but it would not crash if I started a debugging session and stepped through the code.
2015-05-04 16:09:51.569 ToDoList[9223:67681] -[AddToDoItemViewController textField:]: unrecognized selector sent to instance 0x7fe570d4eff0
2015-05-04 16:09:51.574 ToDoList[9223:67681] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[AddToDoItemViewController textField:]: unrecognized selector sent to instance 0x7fe570d4eff0'
Then I solved the mystery by reading out this post: IOS Tutorial Exception (ToDo Sample)
The reason was that I wrongly connected the text field to the #implemenation section instead of to the #interface section and it created some method that I deleted. Of course I forgot about that soon after that.
How could I have figured out myself without knowing anything of the above what was the reason to get that exception and where it came from?
Log message is telling you that something was trying to call -textField: method of your AddToDoItemViewController.
So the first step would be to check if that method is implemented - in your case it was not. You might have been confused by the presence of
#property(weak, nonatomic) IBOutlet UITextField* textField
but auto synthesis for property generates getter with the signature -textField, which is different from -textField: (latter takes one parameter, while former none).
The exception says that you're trying to access the textView property of AddToDoItemViewController, but it doesn't have one.
So your next step would've been to go and check that you have a property like that declared and being an outlet that it's properly connected in the Interface Builder.
Edit:
Sorry I wasn't paying enough attention.
The selector that it's trying to call is textField: so it must be a function starting like that. I assume you set the controller as a TextView delegate but didn't implement the required method.
I have a Ruby on Rails application that has an API, it's an OAuth 2.0 provider and uses Doorkeeper. I am creating an iPhone client for that application and am using the gtm-oauth2 library for authentication. Here is the Github repository for the iPhone app.
I manage do the authentication request using the library and get the response from the OAuth server, but (I think that) when the iPhone app receives the response, the iPhone app crashes. I get the following error:
2013-03-25 07:30:51.563 Catapult for iOS[68917:c07] -[NSNull length]: unrecognized selector sent to instance 0x14f2678
2013-03-25 07:30:51.564 Catapult for iOS[68917:c07] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[NSNull length]: unrecognized selector sent to instance 0x14f2678'
*** First throw call stack:
(0x13c1012 0x11e6e7e 0x144c4bd 0x13b0bbc 0x13b094e 0xf074 0x185e3 0x13b51bd 0x13b50d6 0x1531a 0x1512b 0x14ae2 0x13b51bd 0x13b50d6 0x11d0a 0x1032a 0x13b51bd 0x13b50d6 0x79be 0x77ed 0x8cf2 0xcec589 0xcea652 0xceb89a 0xcea60d 0xcea785 0xc37a68 0x4a2a911 0x4a29bb3 0x4a67cda 0x13638fd 0x4a6835c 0x4a682d5 0x4952250 0x1344f3f 0x1344a39 0x1367734 0x1366f44 0x1366e1b 0x22be7e3 0x22be668 0x12affc 0x2c6d 0x2b95)
libc++abi.dylib: terminate called throwing an exception
I am a complete noob/beginner when it comes to iOS development and Objective-C programming, and I am learning how to create my first app using this little project. I asked the same question in the gtm-oaut2 Google Group and according to them, the problem comes from my code and not the library. The problem is that all of my code is taken from their wiki and I can't pinpoint where the app crashes. If I understand correctly, at some point I am calling length of NSNull, but I am not calling length anywhere, hence my confusion. Also, when the app crashes, the line hilighted is in the main.m file and the error (on the right label, not in the output) is the following:
Thread 1: signal SIGABRT
I have no clue what that means...
Does anyone know what the problem might be please?
You're right that the issue is that somewhere you've got the length message being sent to an instance of NSNull. To pinpoint where exactly this is happening set a breakpoint on objc_exception_throw. You can do this in the Xcode UI with little "+" button in the bottom left corner on the breakpoints tab. Select "Add Exception breakpoint." Then the debugger will stop your program at the point where the error occurs instead of waiting for the program to actually crash.
Well... you understood the error correctly.. You are somewhere calling length on a NSNull instance.
I must find out where this is happening.
I think this is happening in a JSON response. Maybe you (or "the code") is calling length on something it expects its a NSString but it is instead NSNull (that is the json has a NULL value).
Try if you manage to print the json response and see if you found a key mapped to a null value...
NSNull does not respond to length
You can check the documentation for NSNull to see that this is the case.
Without having an idea of what your code base is doing I am not sure where to look, you must be calling [NSNull null]; at some point to get the NSNull object or you are using a framework somewhere that returns this.
I'm getting an "unrecognized selector" error that is confusing me.
I know that I can "po" the pointer in LLDB to find out about the receiver. But is there a way to deduce which object is sending this message?
Thanks!
The command bt in the debugger will show you a backtrace (stacktrace), which should give you the class that initiated the message somewhere in that output.
Backtrace doesn't always help if you're dealing with multiple threads - you end up with the backtrace of the exception handler on the main thread which isn't necessarily the one that cause the error.
However, since you know that the particular selector doesn't exist for a particular class, you can cheat a little by using a category to add the selector to the class, then just stick a breakpoint on it.
For example, for this error:
-[__NSCFDictionary isEqualToString:]: unrecognized selector sent to instance 0x10004fb0
we know that something's trying to call "NSDictionary" with "isEqualToString". So, add this at the end of any file you like, outside any other "#implementation" blocks:
#implementation NSDictionary(debug)
- (BOOL)isEqualToString:(NSString*)theString {
return FALSE;
}
#end
Stick a breakpoint on this, re-run your code and you will get a genuine stack trace. Don't forget to remove the category once you've found the error!
cell.textLabel.text = operationEnt.operationNaam;
on this line of code I get the error:
*** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[__NSCFString operationNaam]: unrecognized selector sent to instance 0x6bce400'
But operationNaam is an attribute defined as a String. So I'm wondering, where is my mistake.
This is when I try to fill my cells of my TableView.
That exception means that the message operationNaam is being sent to a NSString object, and NSString does not recognize that message selector.
This means that your operationEnt object has somehow become a NSString during runtime.
Possibly, you did this...
operationEnt = someString;
when you meant this...
operationEnt.operationNaam = someString;
It seems that you either have memory management issues or misunderstand Objective-C's property accessor syntax.o operationEnt keeps becoming an NSString which doesn't respond to that particular property getter message, hence the crash. (Watch out for overreleases!)
I'm trying to develop an app that can show a PDF file. I try to complete this with ZoomingPDFViewer
http://developer.apple.com/library/ios/#samplecode/ZoomingPDFViewer/Introduction/Intro.html#//apple_ref/doc/uid/DTS40010281-Intro-DontLinkElementID_2
code that is in the apple library. When I mix that code with my code some function doesn't work. And if I make it with the same code (don't mixed) the app throw this error:
* Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[UIView setPDFPage:]: unrecognized selector sent to instance 0x6a833f0'
I'm in SDK 5.0 the requirements says that I should compile it in SDK 5.1 but the sample runs perfect, the problem is in my project but I don't know what is my error.
I'll appreciate if someone can help me with this strange error.
Check the Class setting in Storyboard.
View Controller -> Custom Class: ZoomingPDFViewerViewController and
Scroll VIew -> Custom Class: PDFScrollView
The second setting is the cause of your error.
You seem to be sending -setPDFPage: to an uncast self.view object. Try casting before calling like so:
[(PDFScrollView *)self.view setPDFPage:PDFPage];
Double check your connections in IB, if you are using it, or make sure you are initing a PDFScrollView* object in -loadView if not.