Shadow not appearing for UIView using CALayer - iphone

Question

I have a subclassed UIView loaded from a nib, and I cannot get a shadow to draw around it. I'm trying to get a shadow to appear around the entire view for quite some time now. I elected to place it in it's own sublayer to simplify animating it later. Here's the code:
-(void)awakeFromNib
{
self.clipsToBounds = NO;
// set up the shadow layer
CALayer *shadow = [CALayer layer];
shadow.frame = CGRectMake(self.frame.origin.x, self.frame.origin.y, self.bounds.size.width, self.bounds.size.height);
shadow.shadowColor = [UIColor blueColor].CGColor;
shadow.shadowRadius = 15.0;
shadow.opacity = 1.0;
[self.layer addSublayer:shadow];
// I set this property so I have access to it later to more easily animate it.
self.shadowLayer = shadow;
}
When I NSLog the shadowLayer property, the coordinates and frame are correct. It's matches the view it's backing.
I also set a border color and corner radius on self.layer and it appears correctly. If I put the shadow on self.layer it appears but it encompasses all the subviews of my parent UIView.
Any help is greatly appreciated.

Answer 1

Am assuming you have QuartzCore imported. I think you need to set & create a border to the UIView. The way to use this [self roundedLayerWithShadow:yourView.layer radius:5.0f];
- (void)roundedLayerWithShadow:(CALayer *)viewLayer
radius:(float)r
{
[viewLayer setMasksToBounds:YES];
[viewLayer setCornerRadius:r];
[viewLayer setBorderColor:[RGB(180, 180, 180) CGColor]];
[viewLayer setBorderWidth:1.0f];
[viewLayer setShadowColor:[RGB(0, 0, 0) CGColor]];
[viewLayer setShadowOffset:CGSizeMake(0, 0)];
[viewLayer setShadowOpacity:1];
[viewLayer setShadowRadius:2.0];
return;
}

Answer 2

I struggled with the same, and it turns out you need to set shadowOpacity to 1.0. In your code you accidentally use opacity instead of shadowOpacity. That's the same issue I had.

Answer 3

In general, for the shadow to appear:
the shadowOpacity should be larger than 0
the shadowRadius should be larger than 0
the masksToBounds should be set to false (to avoid the clipping of the shadow)
the shadowColor should be different than the background color of the view's superview
Swift 4.2. example implementation:
let myCustomView = MyCustomView()
myCustomView.layer.shadowColor = UIColor.black.cgColor
myCustomView.layer.shadowOpacity = 0.15
myCustomView.layer.shadowRadius = 5
myCustomView.layer.masksToBounds = false
myCustomView.layer.shadowOffset = CGSize(width: 0, height: 2)

Answer 4

Aside from borderRadius, your shadow layer looks very much transparent. Therefore it will not drop any shadow on shadow.superlayer.