Push from navigation controller after do something in background - ios

Question

I create a method to do something in background and manipulate ui on foreground. In background i still do nothing right now/ but later i want to take one core data object and On foreground i push from active navigation controller.
When I do that I got this error :
Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: ' -[__NSArrayM insertObject:atIndex:]: object cannot be nil'
This is a piece of my code :
[[NSOperationQueue new] addOperationWithBlock:^{
[[NSOperationQueue mainQueue]addOperationWithBlock:^{
//theCatalog is not nil here just FYI
PO1(theCatalog); //just for log the catalog object
[theCatalog showImageForThisCatalogwithNavigationController:self.delegateBGCatalogSearchTableCellResultProtocol.navigationController withPage:pageNumber];
}];
}];
But when i just call this, my code doesn't give error like that.
[theCatalog showImageForThisCatalogwithNavigationController:self.delegateBGCatalogSearchTableCellResultProtocol.navigationController withPage:pageNumber];
Basically, the code simply won't run in any block.
I can run
[theCatalog showImageForThisCatalogwithNavigationController:self.delegateBGCatalogSearchTableCellResultProtocol.navigationController withPage:pageNumber]; just fine
Bit if I run
[[NSOperationQueue mainQueue]addOperationWithBlock:^{
[theCatalog showImageForThisCatalogwithNavigationController:self.delegateBGCatalogSearchTableCellResultProtocol.navigationController withPage:pageNumber];
//theCatalog is not nil here just FYI
}];
Which is almost equivalent, then I got that error. I can't know where the error is. I just get redirected to main() and the program crash there.
This is the full error code
2014-09-18 18:15:52.808 [1735:60b] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '*** -[__NSArrayM insertObject:atIndex:]: object cannot be nil'
*** First throw call stack:
(0x2f262fd3 0x39a0fccf 0x2f19cf9d 0x31b15c6f 0x31b15aab 0x31b15633 0x31b2cf49 0x31b2cb8d 0x31b2cb25 0x31a7ed79 0x316fc62b 0x316f7e3b 0x316f7ccd 0x316f76df 0x316f74ef 0x316f121d 0x2f22e2a5 0x2f22bc49 0x2f22bf8b 0x2f196f4f 0x2f196d33 0x3409b663 0x31ae216d 0xc91cd 0x39f1cab7)
Perhaps numbers below First throw call stack, which are (0x2f262fd3 0x39a0fccf 0x2f19cf9d 0x31b15c6f 0x31b15aab 0x31b15633 0x31b2cf49 0x31b2cb8d 0x31b2cb25 0x31a7ed79 0x316fc62b 0x316f7e3b 0x316f7ccd 0x316f76df 0x316f74ef 0x316f121d 0x2f22e2a5 0x2f22bc49 0x2f22bf8b 0x2f196f4f 0x2f196d33 0x3409b663 0x31ae216d 0xc91cd 0x39f1cab7) could help to debug but I have no idea what those are.
libc++abi.dylib: terminating with uncaught exception of type NSException
Right now i got another first throw call stack like this 2014-09-19 14:13:19.595[18059:60b] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '*** -[__NSArrayM insertObject:atIndex:]: object cannot be nil'
*** First throw call stack:
(
0 CoreFoundation 0x05e501e4 __exceptionPreprocess + 180
1 libobjc.A.dylib 0x02c258e5 objc_exception_throw + 44
2 CoreFoundation 0x05e02abc -[__NSArrayM insertObject:atIndex:] + 844
3 CoreFoundation 0x05e02760 -[__NSArrayM addObject:] + 64
4 UIKit 0x012e8050 -[UINavigationBar pushNavigationItem:] + 244
5 UIKit 0x012e73b7 -[UINavigationBar _pushNavigationItem:transition:] + 429
6 UIKit 0x01389fee __71-[UINavigationController pushViewController:transition:forceImmediate:]_block_invoke + 207
7 UIKit 0x01388a2d -[UINavigationController _startDeferredTransitionIfNeeded:] + 998
8 UIKit 0x013894e9 -[UINavigationController __viewWillLayoutSubviews] + 57
9 UIKit 0x014ca0d1 -[UILayoutContainerView layoutSubviews] + 213
10 UIKit 0x11ebd21b -[UILayoutContainerViewAccessibility(SafeCategory) layoutSubviews] + 50
11 UIKit 0x012b1964 -[UIView(CALayerDelegate) layoutSublayersOfLayer:] + 355
12 libobjc.A.dylib 0x02c3782b -[NSObject performSelector:withObject:] + 70
13 QuartzCore 0x00f3b45a -[CALayer layoutSublayers] + 148
14 QuartzCore 0x00f2f244 _ZN2CA5Layer16layout_if_neededEPNS_11TransactionE + 380
15 QuartzCore 0x00f2f0b0 _ZN2CA5Layer28layout_and_display_if_neededEPNS_11TransactionE + 26
16 QuartzCore 0x00e957fa _ZN2CA7Context18commit_transactionEPNS_11TransactionE + 294
17 QuartzCore 0x00e96b85 _ZN2CA11Transaction6commitEv + 393
18 QuartzCore 0x00e97258 _ZN2CA11Transaction17observer_callbackEP19__CFRunLoopObservermPv + 92
19 CoreFoundation 0x05e1836e __CFRUNLOOP_IS_CALLING_OUT_TO_AN_OBSERVER_CALLBACK_FUNCTION__ + 30
20 CoreFoundation 0x05e182bf __CFRunLoopDoObservers + 399
21 CoreFoundation 0x05df6254 __CFRunLoopRun + 1076
22 CoreFoundation 0x05df59d3 CFRunLoopRunSpecific + 467
23 CoreFoundation 0x05df57eb CFRunLoopRunInMode + 123
24 GraphicsServices 0x034f95ee GSEventRunModal + 192
25 GraphicsServices 0x034f942b GSEventRun + 104
26 UIKit 0x01242f9b UIApplicationMain + 1225
27 0x0000291d main + 141
28 libdyld.dylib 0x03118701 start + 1
29 ??? 0x00000001 0x0 + 1
)