What causes this error? “CALayer position contains NaN: [240 nan]”

Question

I\'ve seen this happen whenever i rotate a screen that has a UITableView on it. I\'ve found out that it happens inbetween the willRotate and

Answer 1

This error also cost me a long time.
At the end I found my colleague wrote something like this:

UIEdgeInsets a;
a.left = (...some calculation);
button.imageEdgeInsets = a;

And I rewrote these code like this and fix the issue:

UIEdgeInsets a;
a.left = (...some calculation);
a.top = 0;
a.bottom = 0;
a.right = 0;
button.imageEdgeInsets = a;

some value of UIEdgeInsets isn't initialised properly, and it sometimes turn into a NaN value, and crash the application.
More generally, you should check whether all values of C-style structs are initialised properly.