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

I've found the problem.

When you reset the frame of a tableview, it calls the delegate method tableView:heightForRowAtIndexPath: for each row in the table so it can recalculate its content size if it needs to. At that point, we do some special handling to return the height, and due to some bad assumptions in our code, we mistakenly returned NaN due to a divide by zero error (the variable we divide by was assumed to never be zero). Making sure that we do not divide by zero here fixed it.