在iOS 9(Xcode 7)中使用UICollectionViewLayoutAttributes时的EXC_ARITHMETIC

Question

在Xcode 7,iOS 9中运行我的应用程序时出现EXC_ARITHMETIC错误.但它在下载版本中运行良好(Xcode 6.4,iOS 8.4)

请在下面找到代码

UICollectionViewFlowLayout *flowlayout = (UICollectionViewFlowLayout *)self.collectionViewLayout;
    NSUInteger count = _tripButtons.count;
    for (NSUInteger i = 0; i < count; ++i)
{
        UIView *tripButton = [_tripButtons pointerAtIndex:i];
        if (tripButton)
     {
            CGRect frame = tripButton.frame;
               // Getting error with below line
                UICollectionViewLayoutAttributes *layout = [flowlayout layoutAttributesForItemAtIndexPath:[NSIndexPath indexPathForItem:i inSection:0]];
                frame.origin.x = layout.frame.origin.x;
                frame.origin.y = layout.frame.origin.y;
                tripButton.frame = frame;



        }
    }

我对这个错误很困惑.这个错误是由于我的代码中的错误还是由于我的升级造成的.请指导我......