* Terminating app due to uncaught exception 'CALayerInvalidGeometry', reason: 'CALayer position contains NaN: [nan 40]'
今天早上上班，发现程序就直接挂了，昨天调得好好的，怎么来上班就挂了呢？
栈信息打印如下：
2015-10-20 10:01:12.871 Putaoji[49129:1691777] *** Terminating app due to uncaught exception 'CALayerInvalidGeometry', reason: 'CALayer position contains NaN: [nan 40]' *** First throw call stack: ( 0 CoreFoundation 0x000000010df49f65 __exceptionPreprocess + 165 1 libobjc.A.dylib 0x000000010d244deb objc_exception_throw + 48 2 CoreFoundation 0x000000010df49e9d +[NSException raise:format:] + 205 3 QuartzCore 0x000000010cc2f7e6 _ZN2CA5Layer12set_positionERKNS_4Vec2IdEEb + 152 4 QuartzCore 0x000000010cc2f959 -[CALayer setPosition:] + 44 5 QuartzCore 0x000000010cc2ffbd -[CALayer setFrame:] + 650 6 UIKit 0x000000010e9673f7 -[UIView(Geometry) setFrame:] + 356 7 UIKit 0x000000010ec50422 -[UIButton _setFrame:deferLayout:] + 125 8 UIKit 0x000000010ec50522 -[UIButton setFrame:] + 178 9 Putaoji 0x000000010ae41132 -[PTJInviteFriendsViewController createShareButtonWithFrame:atIndex:title:imageName:] + 690 10 Putaoji 0x000000010ae4004b -[PTJInviteFriendsViewController setupUI] + 2715 11 Putaoji 0x000000010ae3f5a4 -[PTJInviteFriendsViewController viewDidLoad] + 228 12 UIKit 0x000000010ea59931 -[UIViewController loadViewIfRequired] + 1344 13 UIKit 0x000000010ea5f923 -[UIViewController __viewWillAppear:] + 120 14 UIKit 0x000000010ea8f18a -[UINavigationController _startCustomTransition:] + 1177 15 UIKit 0x000000010ea9e7c7 -[UINavigationController _startDeferredTransitionIfNeeded:] + 712 16 UIKit 0x000000010ea9f67d -[UINavigationController __viewWillLayoutSubviews] + 57 17 UIKit 0x000000010ec3763d -[UILayoutContainerView layoutSubviews] + 248 18 UIKit 0x000000010e97f11c -[UIView(CALayerDelegate) layoutSublayersOfLayer:] + 710 19 QuartzCore 0x000000010cc3836a -[CALayer layoutSublayers] + 146 20 QuartzCore 0x000000010cc2cbd0 _ZN2CA5Layer16layout_if_neededEPNS_11TransactionE + 366 21 QuartzCore 0x000000010cc2ca4e _ZN2CA5Layer28layout_and_display_if_neededEPNS_11TransactionE + 24 22 QuartzCore 0x000000010cc211d5 _ZN2CA7Context18commit_transactionEPNS_11TransactionE + 277 23 QuartzCore 0x000000010cc4e9f0 _ZN2CA11Transaction6commitEv + 508 24 UIKit 0x000000010e8f853a _afterCACommitHandler + 174 25 CoreFoundation 0x000000010de759d7 __CFRUNLOOP_IS_CALLING_OUT_TO_AN_OBSERVER_CALLBACK_FUNCTION__ + 23 26 CoreFoundation 0x000000010de75947 __CFRunLoopDoObservers + 391 27 CoreFoundation 0x000000010de6b59b __CFRunLoopRun + 1147 28 CoreFoundation 0x000000010de6ae98 CFRunLoopRunSpecific + 488 29 GraphicsServices 0x0000000112b04ad2 GSEventRunModal + 161 30 UIKit 0x000000010e8ce676 UIApplicationMain + 171 31 Putaoji 0x000000010af306ff main + 111 32 libdyld.dylib 0x000000010fe9d92d start + 1 ) libc++abi.dylib: terminating with uncaught exception of type NSException (lldb)
解决方法：
实际标题已经很清楚的写到：>* Terminating app due to uncaught exception 'CALayerInvalidGeometry', reason: 'CALayer position contains NaN: [nan 40]'
意思是说程序崩溃是CALayer的位置中含有不存在的数,说白了就是你的View.frame 中计算的时候，有的地方除以0了。例如在我的程序中计算的时候：
CGFloat leftSpace = 24.0f; CGFloat width = SCREENWIDTH; CGFloat itemWH = 80.0-22.0; NSInteger count = shareTitleArray.count; CGFloat innerSpace = (width -leftSpace*2 - itemWH *count)/(shareTitleArray.count -1); for (int i = 0; i<shareTitleArray.count; i++)
{ CGFloat x = leftSpace+i*(innerSpace+itemWH); CGRect frame = CGRectMake(x, 11, itemWH, itemWH);
[self createShareButtonWithFrame:frame atIndex:i title:shareTitleArray[i] imageName:shareImageArray[i]];
}
仔细一看没有什么问题，但是如果shareTitleArray数组中的个数为1的情况的下，就会导致除以0，从而导致程序崩溃。
