iPhone UITableViewCell layer shadow

问题

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);

回答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

回答2:

Just adding the @Paul Soult answer in Swift:

cell?.layer.shadowOffset = CGSizeMake(0, 1)
cell?.layer.shadowColor = UIColor.blackColor().CGColor
cell?.layer.shadowRadius = 1
cell?.layer.shadowOpacity = 0.6

// Maybe just me, but I had to add it to work:
cell?.clipsToBounds = false

let shadowFrame: CGRect = (cell?.layer.bounds)!
let shadowPath: CGPathRef = UIBezierPath(rect: shadowFrame).CGPath
cell?.layer.shadowPath = shadowPath

回答3:

The view hierarchy of a grouped table view cell is really rather opaque. cell.layer is actually referring to the layer of the main view of the cell, which takes of the entire width of the table. The rounded part of the cell that is inset is actually handled by apple's private methods for drawing grouped cells.

You're probably going to have more luck creating a custom subclass of UITableViewCell.

来源：https://stackoverflow.com/questions/3546880/iphone-uitableviewcell-layer-shadow

标签

iphone

cocoa-touch

uitableview

Shadow