Question

My main xib file has a tab bar controller and each tab is linked to a different xib.

One of the tabs is a nav controller and its view controller is linked to a xib as per this answer.

When I run the app I get the below error. its as if its not even looking in the view controller for these methods.

i have tried everything including using a different xib, checking the links in interface builder i.e. the tableview’s delegate and datasource. i have implemented the required protocol methods in the vc e.g. numberofrowsinsection.

as soon as i remove the datasource link in the xib the error goes away.

EDIT: When I add this view controller’s view to the main window (just to test) the tableview loads without issues. So it seems it only happens when I use it as part of the nav controller and tab controller.

Terminating app due to uncaught exception
‘NSInvalidArgumentException’, reason: ‘-[UIViewController
tableView:numberOfRowsInSection:]: unrecognized selector sent to
instance 0x6120ae0’
* Call stack at first throw: ( 0 CoreFoundation
0x00dc45a9 exceptionPreprocess + 185 1 libobjc.A.dylib
0x00f18313 objc_exception_throw + 44 2 CoreFoundation
0x00dc60bb -[NSObject(NSObject) doesNotRecognizeSelector:] + 187 3
CoreFoundation 0x00d35966 __forwarding + 966
4 CoreFoundation 0x00d35522
_CF_forwarding_prep_0 + 50 5 UIKit
0x001d32b7 -[UISectionRowData
refreshWithSection:tableView:tableViewRowData:] + 1834 6 UIKit
0x001d0d88 -[UITableViewRowData numberOfRows] + 108 7 UIKit
0x00084677 -[UITableView noteNumberOfRowsChanged] + 132 8 UIKit
0x00091708 -[UITableView reloadData] + 773 9 UIKit
0x0008e844 -[UITableView layoutSubviews] + 42 10 QuartzCore
0x016aea5a -[CALayer layoutSublayers] + 181 11 QuartzCore
0x016b0ddc CALayerLayoutIfNeeded + 220 12 QuartzCore
0x016560b4 _ZN2CA7Context18commit_transactionEPNS_11TransactionE + 310
13 QuartzCore 0x01657294
_ZN2CA11Transaction6commitEv + 292 14 QuartzCore
0x0165746d
_ZN2CA11Transaction17observer_callbackEP19__CFRunLoopObservermPv + 99
15 CoreFoundation 0x00da589b
CFRUNLOOP_IS_CALLING_OUT_TO_AN_OBSERVER_CALLBACK_FUNCTION + 27 16
CoreFoundation 0x00d3a6e7 __CFRunLoopDoObservers
+ 295 17 CoreFoundation 0x00d031d7
__CFRunLoopRun + 1575 18 CoreFoundation
0x00d02840 CFRunLoopRunSpecific + 208 19 CoreFoundation
0x00d02761 CFRunLoopRunInMode + 97 20 GraphicsServices
0x00ffc1c4 GSEventRunModal + 217 21 GraphicsServices
0x00ffc289 GSEventRun + 115 22 UIKit
0x00024c93 UIApplicationMain + 1160 23 MyPractice
0x00002339 main + 121 24 MyPractice
0x000022b5 start + 53 ) terminate called after throwing an instance of
‘NSException’

Answer 1

This log message:

[UIViewController tableView:numberOfRowsInSection:]: unrecognized selector sent to instance 

Implies that the UITableView dataSource method is being sent to an instance of UIViewController, not an instance of your subclass. How are you initialising your VC? If you’re initialising it from within a XIB, have you correctly set the VC’s class to your subclass?