exception 'CALayerInvalidGeometry', reason:

Terminating app due to uncaught exception 'CALayerInvalidGeometry', reason: 'CALayer position contains NaN: [nan 160]'

*** First throw call stack:

(0x181e32530 0x192dbc0e4 0x181e32470 0x185f8877c 0x185f886d4 0x185f88664 0x186639a3c 0x18664dc14 0x10013259c 0x100137b48 0x10011d644 0x1869374b8 0x18692c06c 0x186720c44 0x18663d4a4 0x185f917a8 0x185f8c378 0x185f8c21c 0x185f8ba14 0x185f8b798 0x185f851c8 0x181dead98 0x181de7d24 0x181de8104 0x181d151f4 0x18b13f6fc 0x1866a610c 0x1001d0bdc 0x19343aa08)

libc++abi.dylib: terminating with uncaught exception of type NSException

把除0得地方给判断一下就ok了