cocoa touch - iPhone UITableViewCell layer shadow

Question

I'm trying to add a shadow to a UITableViewCell using the layer.shadowColor, Offset, Radius but it doesn't seem to affect it in any way. The table is grouped style. Any ideas why?

Here is the code i'm using:

cell.layer.shadowColor= [UIColor blackColor].CGColor;
cell.layer.shadowRadius = 5.0;
cell.layer.shadowOffset = CGSizeMake(10, 10);

Answer 1

You need to also set the shadow opacity, it defaults to 0 and you won't see anything if you don't explicitly set it.

CALayer Reference

cell.layer.shadowOffset = CGSizeMake(1, 0);
cell.layer.shadowColor = [[UIColor blackColor] CGColor];
cell.layer.shadowRadius = 5;
cell.layer.shadowOpacity = .25;

Also note, that if you don't set the shadow path you will have terrible performance on the iPhone/iPad. Use something like the following code to set a shadow path, it removes the need to blur the layers underneath your tableviewcell's to create a "high quality" shadow.

CGRect shadowFrame = cell.layer.bounds;
CGPathRef shadowPath = [UIBezierPath bezierPathWithRect:shadowFrame].CGPath;
cell.layer.shadowPath = shadowPath;

Watch video 425 (also 424 and 426) to learn more about shadows from the WWDC 2010 Videos available here: WWDC 2010 Session Videos