NSUnknownKeyException that I can't find a fix for

Question

I'm working on learning iOS development over summer break and I'm trying to write a simple app for converting a base-10 number to binary, octal, hex, etc., but I keep getting an NSUnknownKeyException and my app won't even start in the simulator. I've pored over the internet for a solution, but none worked for me. This is the message I get in the console.

2013-06-15 23:48:45.256 AnyBase Converter[8584:c07] *** Terminating app due to uncaught exception 'NSUnknownKeyException', reason: '[<ABCViewController 0x7591340> setValue:forUndefinedKey:]: this class is not key value coding-compliant for the key display.'
*** First throw call stack:
(0x1c91012 0x10cee7e 0x1d19fb1 0xb7ae41 0xafc5f8 0xafc0e7 0xb26b58 0x230019 0x10e2663 0x1c8c45a 0x22eb1c 0xf37e7 0xf3dc8 0xf3ff8 0xf4232 0x433d5 0x4376f 0x43905 0xc47aab6 0x4c917 0x1096c 0x1194b 0x22cb5 0x23beb 0x15698 0x1becdf9 0x1becad0 0x1c06bf5 0x1c06962 0x1c37bb6 0x1c36f44 0x1c36e1b 0x1117a 0x12ffc 0x273d 0x2665 0x1)
libc++abi.dylib: terminate called throwing an exception

When I create a breakpoint on exceptions, it gives me a breakpoint at

return UIApplicationMain(argc, argv, nil, NSStringFromClass([ABCAppDelegate class]));

in main.m. I read one answer on Stack Overflow that said there might be a problem with the key "display" (i.e. I might not have remembered to synthesize it), but I don't even have a key named "display" anywhere. I searched the entire workspace, and the search came up empty. Does anyone have any idea what it might be?

Can you share more code? For example, the code in your ABCViewController — LuisCien, Jun 16 '13 at 04:09

score 0 · Accepted Answer · answered Jun 16 '13 at 04:33

0

You have either done something wrong with your xib file or something wrong with the code file which is file owner of your controller ABCViewController.

Check the connection of IBOutlet and file owner again. It should resolve your problem.

answered Jun 16 '13 at 04:33

Apurv

17,116
8
51
67

I had changed the name associated with one of my buttons. Clicking the "X" next to the wrong entry under "Referencing Outlets" in the Connections Inspector fixed my issue. Thank you! – Matt Shank Jun 16 '13 at 04:37
Glad it help..Enjoy your summer break..!! – Apurv Jun 16 '13 at 04:38

score 0 · Answer 2 · answered Jun 16 '13 at 04:36

This error often occurs when a nib or storyboard has connections to outlets which are not present in an object at run time -- for example, if you made a connection in IB and then later change the name of the IBOutlet property to which it was connected.

Take a look at your ABCViewController in IB. In the Connections pane of the inspector, you'll probably see the faulty connection identified with a "!" icon.

NSUnknownKeyException that I can't find a fix for

2 Answers2