when i run my app, i received this error :
2014-08-11 10:52:10.546 ControlViewTest[918:60b] -[UIViewController collectionView:numberOfItemsInSection:]: unrecognized selector sent to instance 0x8c862f0
2014-08-11 10:52:10.605 ControlViewTest[918:60b] * Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[UIViewController collectionView:numberOfItemsInSection:]: unrecognized selector sent to instance 0x8c862f0'
* First throw call stack:
(
0 CoreFoundation 0x017ec1e4 exceptionPreprocess + 180
1 libobjc.A.dylib 0x0156b8e5 objc_exception_throw + 44
2 CoreFoundation 0x01889243 -[NSObject(NSObject) doesNotRecognizeSelector:] + 275
3 CoreFoundation 0x017dc50b ___forwarding_ + 1019
4 CoreFoundation 0x017dc0ee _CF_forwarding_prep_0 + 14
5 UIKit 0x008b0c34 -[UICollectionViewData _updateItemCounts] + 331
6 UIKit 0x008b0ce1 -[UICollectionViewData _validateItemCounts] + 45
7 UIKit 0x008b2c64 -[UICollectionViewData numberOfSections] + 35
8 UIKit 0x0087d6ed -[UICollectionView numberOfSections] + 62
9 UIKit 0x0089d614 -[UICollectionViewFlowLayout(Internal) _getSizingInfos] + 205
10 UIKit 0x0089e48f -[UICollectionViewFlowLayout(Internal) _fetchItemsInfo] + 521
11 UIKit 0x00899fe2 -[UICollectionViewFlowLayout prepareLayout] + 157
12 UIKit 0x008b0d9d -[UICollectionViewData _prepareToLoadData] + 76
13 UIKit 0x008b15c5 -[UICollectionViewData validateLayoutInRect:] + 56
14 UIKit 0x00877603 -[UICollectionView layoutSubviews] + 173
15 UIKit 0x0029a964 -[UIView(CALayerDelegate) layoutSublayersOfLayer:] + 355
16 libobjc.A.dylib 0x0157d82b -[NSObject performSelector:withObject:] + 70
17 QuartzCore 0x03c5745a -[CALayer layoutSublayers] + 148
18 QuartzCore 0x03c4b244 _ZN2CA5Layer16layout_if_neededEPNS_11TransactionE + 380
19 QuartzCore 0x03c573a5 -[CALayer layoutIfNeeded] + 160
20 UIKit 0x0035cae3 -[UIViewController window:setupWithInterfaceOrientation:] + 304
21 UIKit 0x00272aa7 -[UIWindow _setRotatableClient:toOrientation:updateStatusBar:duration:force:isRotating:] + 5212
22 UIKit 0x00271646 -[UIWindow _setRotatableClient:toOrientation:updateStatusBar:duration:force:] + 82
23 UIKit 0x00271518 -[UIWindow _setRotatableViewOrientation:updateStatusBar:duration:force:] + 117
24 UIKit 0x002715a0 -[UIWindow _setRotatableViewOrientation:duration:force:] + 67
25 UIKit 0x0027063a 57-[UIWindow _updateToInterfaceOrientation:duration:force:]_block_invoke + 120
26 UIKit 0x0027059c -[UIWindow _updateToInterfaceOrientation:duration:force:] + 400
27 UIKit 0x002712f3 -[UIWindow setAutorotates:forceUpdateInterfaceOrientation:] + 870
28 UIKit 0x002748e6 -[UIWindow setDelegate:] + 449
29 UIKit 0x0034eb77 -[UIViewController _tryBecomeRootViewControllerInWindow:] + 180
30 UIKit 0x0026a474 -[UIWindow addRootViewControllerViewIfPossible] + 591
31 UIKit 0x0026a5ef -[UIWindow _setHidden:forced:] + 312
32 UIKit 0x0026a86b -[UIWindow _orderFrontWithoutMakingKey] + 49
33 UIKit 0x002753c8 -[UIWindow makeKeyAndVisible] + 65
34 UIKit 0x00225bc0 -[UIApplication _callInitializationDelegatesForURL:payload:suspended:] + 2097
35 UIKit 0x0022a667 -[UIApplication _runWithURL:payload:launchOrientation:statusBarStyle:statusBarHidden:] + 824
36 UIKit 0x0023ef92 -[UIApplication handleEvent:withNewEvent:] + 3517
37 UIKit 0x0023f555 -[UIApplication sendEvent:] + 85
38 UIKit 0x0022c250 _UIApplicationHandleEvent + 683
39 GraphicsServices 0x037e1f02 _PurpleEventCallback + 776
40 GraphicsServices 0x037e1a0d PurpleEventCallback + 46
41 CoreFoundation 0x01767ca5 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE1_PERFORM_FUNCTION + 53
42 CoreFoundation 0x017679db __CFRunLoopDoSource1 + 523
43 CoreFoundation 0x0179268c __CFRunLoopRun + 2156
44 CoreFoundation 0x017919d3 CFRunLoopRunSpecific + 467
45 CoreFoundation 0x017917eb CFRunLoopRunInMode + 123
46 UIKit 0x00229d9c -[UIApplication _run] + 840
47 UIKit 0x0022bf9b UIApplicationMain + 1225
48 ControlViewTest 0x0000264d main + 141
49 libdyld.dylib 0x01e33701 start + 1
)
libc++abi.dylib: terminating with uncaught exception of type NSException
(lldb)somebody can help me pls
Your UICollectionView has a data source set which does not implement the required method collectionView:numberOfItemsInSection:. You need to assign your UICollectionView a valid data source: a class that you've written and that implements collectionView:numberOfItemsInSection:.
来源：https://stackoverflow.com/questions/25239766/libc-abi-dylib-terminating-with-uncaught-exception-of-type-nsexception-collecti