如果不是64位版本，IOS7应用会在模拟器中崩溃，并且在iPhone4和5s上可以正常运行

Question

I am new here and new to iOS programming so bear with me!

I ran into this strange issue. I created an iPhone app which runs fine on my iPhone 5s and iPhone 4. However, when I run it on the iOS Simulator, Version 7.1 (463.9.41), it only runs in 64 bit mode and crashes for all the other modes.

Information based on your suggestions:

1. I renamed the property 'Description', with no changes and exactly the same error message including the word 'Description'. However, the word 'Description' is nowhere in my code anymore.
2. I cleared all contents in the ViewController and it still cranes.
3. All outlets and connections checked and OK.

Any idea what could be the cause?

---

* Terminating app due to uncaught exception 'NSUnknownKeyException', reason: '[ setValue:forUndefinedKey:]: this class is not key value coding-compliant for the key Description.' * First throw call stack:

0   CoreFoundation                      0x018021e4 __exceptionPreprocess + 180
1   libobjc.A.dylib                     0x015818e5 objc_exception_throw + 44
2   CoreFoundation                      0x01891fe1 -[NSException raise] + 17
3   Foundation                          0x01241d9e -[NSObject(NSKeyValueCoding) setValue:forUndefinedKey:] + 282
4   Foundation                          0x011ae1d7 _NSSetUsingKeyValueSetter + 88
5   Foundation                          0x011ad731 -[NSObject(NSKeyValueCoding) setValue:forKey:] + 267

6   Foundation                          0x0120fb0a -[NSObject(NSKeyValueCoding) setValue:forKeyPath:] + 412
7   UIKit                               0x004f81f4 -[UIRuntimeOutletConnection connect] + 106
8   libobjc.A.dylib                     0x015937de -[NSObject performSelector:] + 62
9   CoreFoundation                      0x017fd76a -[NSArray makeObjectsPerformSelector:] + 314
10  UIKit                               0x004f6d4d -[UINib instantiateWithOwner:options:] + 1417
11  UIKit                               0x0035f6f5 -[UIViewController _loadViewFromNibNamed:bundle:] + 280
12  UIKit                               0x0035fe9d -[UIViewController loadView] + 302
13  UIKit                               0x003600d3 -[UIViewController loadViewIfRequired] + 78
14  UIKit                               0x003605d9 -[UIViewController view] + 35
15  UIKit                               0x00280267 -[UIWindow addRootViewControllerViewIfPossible] + 66
16  UIKit                               0x002805ef -[UIWindow _setHidden:forced:] + 312
17  UIKit                               0x0028086b -[UIWindow _orderFrontWithoutMakingKey] + 49
18  UIKit                               0x0028b3c8 -[UIWindow makeKeyAndVisible] + 65
19  UIKit                               0x0023bbc0 -[UIApplication _callInitializationDelegatesForURL:payload:suspended:] + 2097
20  UIKit                               0x00240667 -[UIApplication _runWithURL:payload:launchOrientation:statusBarStyle:statusBarHidden:] + 824
21  UIKit                               0x00254f92 -[UIApplication handleEvent:withNewEvent:] + 3517
22  UIKit                               0x00255555 -[UIApplication sendEvent:] + 85
23  UIKit                               0x00242250 _UIApplicationHandleEvent + 683
24  GraphicsServices                    0x037f7f02 _PurpleEventCallback + 776
25  GraphicsServices                    0x037f7a0d PurpleEventCallback + 46
26  CoreFoundation                      0x0177dca5 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE1_PERFORM_FUNCTION__ + 53
27  CoreFoundation                      0x0177d9db __CFRunLoopDoSource1 + 523
28  CoreFoundation                      0x017a868c __CFRunLoopRun + 2156
29  CoreFoundation                      0x017a79d3 CFRunLoopRunSpecific + 467
30  CoreFoundation                      0x017a77eb CFRunLoopRunInMode + 123
31  UIKit                               0x0023fd9c -[UIApplication _run] + 840
32  UIKit                               0x00241f9b UIApplicationMain + 1225
33  Cards                               0x0000c24d main + 141
34  libdyld.dylib                       0x01e49701 start + 1
)
libc++abi.dylib: terminating with uncaught exception of type NSException

Answer 1

Try to rename property Description to something else. description is read only property of NSObject and some other objects and maybe it collides with your property.

Answer 2

Check your outlets for the Xibs or Storyboards, if one of them is not connected you will get this error. If you are using Key Value Coding then there is a wrong key name (check spelling).

Answer 3

I found the answer.

It happened after I changed the name of my project (top left in the xcode window). When you do this, Xcode asks if it also has to rename a couple of system files to which I answered "yes". After that, the name of my app is changed correctly, but crashes on the simulator unless it runs in 64 bit mode. On the iPhone it works fine in all cases.

Even when I leave all the all the item names unchanged except for the name of the app, the same things happens. When I change the name of the app back, all is OK.

I say it's a bug in Xcode.