旧线程仍然当前…

我编辑了Daniel Gindi的方法，使它可以用于按钮等。 如果有人需要圆角，或者想要将圆角和边框结合起来，它必须在视图层上设置，这个视图层被传递给这个方法。我还设置了栅格化来加快一点。

+ (UIView*)putView:(UIView*)view insideShadowWithColor:(CGColorRef)color 
                                 andRadius:(CGFloat)shadowRadius 
                                 andOffset:(CGSize)shadowOffset 
                                 andOpacity:(CGFloat)shadowOpacity
{
    // Must have same position like "view"
    UIView *shadow = [[UIView alloc] initWithFrame:view.frame]; 

    shadow.layer.contentsScale = [UIScreen mainScreen].scale;
    shadow.userInteractionEnabled = YES; // Modify this if needed
    shadow.layer.shadowColor = color;
    shadow.layer.shadowOffset = shadowOffset;
    shadow.layer.shadowRadius = shadowRadius;
    shadow.layer.masksToBounds = NO;
    shadow.clipsToBounds = NO;
    shadow.layer.shadowOpacity = shadowOpacity;
    shadow.layer.rasterizationScale = [UIScreen mainScreen].scale;
    shadow.layer.shouldRasterize = YES;

    [view.superview insertSubview:shadow belowSubview:view];
    [shadow addSubview:view];

    // Move view to the top left corner inside the shadowview 
    // ---> Buttons etc are working again :)
    view.frame = CGRectMake(0, 0, view.frame.size.width, view.frame.size.height);

    return shadow;
}

这是我的版本在Swift 3的UIView

let corners:UIRectCorner = [.bottomLeft, .topRight]
let path = UIBezierPath(roundedRect: rect, byRoundingCorners: corners, cornerRadii: CGSize(width: radius, height: radius))
let mask = CAShapeLayer()

mask.path = path.cgPath
mask.fillColor = UIColor.white.cgColor

let shadowLayer = CAShapeLayer()
shadowLayer.shadowColor = UIColor.black.cgColor
shadowLayer.shadowOffset = CGSize(width: 0.0, height: 4.0)
shadowLayer.shadowRadius = 6.0
shadowLayer.shadowOpacity = 0.25
shadowLayer.shadowPath = mask.path

self.layer.insertSublayer(shadowLayer, at: 0)
self.layer.insertSublayer(mask, at: 1)

我尝试了这篇文章中的很多解决方案，最终得到了下面的解决方案。这是完全证明解决方案，除非你需要在一个清晰的颜色视图下滴阴影。

- (void)addShadowWithRadius:(CGFloat)shadowRadius withOpacity:(CGFloat)shadowOpacity withOffset:(CGSize)shadowOffset withColor:(UIColor *)shadowColor withCornerradius:(CGFloat)cornerRadius
{
    UIView *viewShadow = [[UIView alloc]initWithFrame:self.frame];
    viewShadow.backgroundColor = [UIColor whiteColor];
    viewShadow.layer.shadowColor = shadowColor.CGColor;
    viewShadow.layer.shadowOffset = shadowOffset;
    viewShadow.layer.shadowRadius = shadowRadius;
    viewShadow.layer.shadowOpacity = shadowOpacity;
    viewShadow.layer.cornerRadius = cornerRadius;
    viewShadow.layer.masksToBounds = NO;
    [self.superview insertSubview:viewShadow belowSubview:self];

    [viewShadow setTranslatesAutoresizingMaskIntoConstraints:NO];
    [self.superview addConstraint:[NSLayoutConstraint constraintWithItem:viewShadow attribute:NSLayoutAttributeWidth relatedBy:NSLayoutRelationEqual toItem:self attribute:NSLayoutAttributeWidth multiplier:1.0 constant:0]];
    [self.superview addConstraint:[NSLayoutConstraint constraintWithItem:viewShadow attribute:NSLayoutAttributeHeight relatedBy:NSLayoutRelationEqual toItem:self attribute:NSLayoutAttributeHeight multiplier:1.0 constant:0]];
    [self.superview addConstraint:[NSLayoutConstraint constraintWithItem:viewShadow attribute:NSLayoutAttributeCenterX relatedBy:NSLayoutRelationEqual toItem:viewShadow attribute:NSLayoutAttributeCenterX multiplier:1.0 constant:0]];
    [self.superview addConstraint:[NSLayoutConstraint constraintWithItem:viewShadow attribute:NSLayoutAttributeCenterY relatedBy:NSLayoutRelationEqual toItem:viewShadow attribute:NSLayoutAttributeCenterY multiplier:1.0 constant:0]];
    [self layoutIfNeeded];

    self.layer.cornerRadius = cornerRadius;
    self.layer.masksToBounds = YES;
}

你需要使用shadowView和roundView

shadowView

必须有背景色 应该躺在roundView后面吗 窍门是将shadowView布局在里面，它的阴影需要发光。调整嵌入，使shadowView在roundView后面完全不可见

圆视图

必须剪辑子视图

的代码

addSubviews(shadowView, roundView)
roundView.addSubviews(titleLabel, subtitleLabel, imageView)

// need inset
shadowView.pinEdges(view: self, inset: UIEdgeInsets(constraintInsets: 2))
roundView.pinEdges(view: self)

do {
  shadowView.backgroundColor = .white // need background
  let layer = shadowView.layer
  layer.shadowColor = UIColor.black.cgColor
  layer.shadowRadius = 3
  layer.shadowOffset = CGSize(width: 3, height: 3)
  layer.shadowOpacity = 0.7
  layer.shouldRasterize = true
}

do {
  roundView.backgroundColor = .white
  let layer = roundView.layer
  layer.masksToBounds = true
  layer.cornerRadius = 5
}

或者你可以在不指定clipToBounds/maskToBounds的情况下这样做

layer.shadowColor = UIColor.gray.cgColor
layer.shadowOffset = CGSize(width: 3, height: 3)
layer.shadowOpacity = 0.8

extension UIView {
    func dropRoundedShadowForAllSides() {
        let backgroundView = UIView(frame:self.frame)
        let radius = frame.height/2
        backgroundView.layer.masksToBounds = false
        self.layer.masksToBounds = true
        backgroundView.layer.shadowOffset = CGSize(width: 0.0, height: 0.0)
        backgroundView.layer.shadowRadius = 4
        backgroundView.layer.shadowOpacity = 0.4

        let path = UIBezierPath()

        // Start at the Top Left Corner + radius distance
        path.move(to: CGPoint(x: 2*radius, y: 0.0))

        // Move to the Top Right Corner - radius distance
        path.addLine(to: CGPoint(x: backgroundView.frame.size.width - radius, y: 0.0))

        // Move to top right corner + radius down as curve
        let centerPoint1 = CGPoint(x:backgroundView.frame.size.width - radius,y:radius)
        path.addArc(withCenter: centerPoint1, radius: radius, startAngle: 3*(.pi/2), endAngle: 0, clockwise: true)

        // Move to the Bottom Right Corner - radius
        path.addLine(to: CGPoint(x: backgroundView.frame.size.width, y: backgroundView.frame.size.height - radius))

        // Move to top right corner + radius left as curve
        let centerPoint2 = CGPoint(x:backgroundView.frame.size.width - radius,y:backgroundView.frame.size.height - radius)
        path.addArc(withCenter: centerPoint2, radius: radius, startAngle: 0, endAngle: .pi/2, clockwise: true)

        // Move to the Bottom Left Corner - radius
        path.addLine(to: CGPoint(x: radius, y: backgroundView.frame.size.height))

        // Move to left right corner - radius up as curve
        let centerPoint3 = CGPoint(x:radius,y:backgroundView.frame.size.height - radius)
        path.addArc(withCenter: centerPoint3, radius: radius, startAngle: .pi/2, endAngle: .pi, clockwise: true)

        // Move to the top Left Corner - radius
        path.addLine(to: CGPoint(x: 0, y: radius))

        // Move to top right corner + radius down as curve
        let centerPoint4 = CGPoint(x:radius,y:radius)
        path.addArc(withCenter: centerPoint4, radius: radius, startAngle: .pi, endAngle: 3 * (.pi/2), clockwise: true)

        path.close()

        backgroundView.layer.shadowPath = path.cgPath
        if let superView = self.superview {
            superView.addSubview(backgroundView)
            superView.sendSubview(toBack: backgroundView)
            superView.bringSubview(toFront: self)
        }

    }
}

我在UIView中创建了一个helper

@interface UIView (Helper)

- (void)roundCornerswithRadius:(float)cornerRadius
               andShadowOffset:(float)shadowOffset;
@end

你可以这样叫它

[self.view roundCornerswithRadius:5 andShadowOffset:5];

这是实现

- (void)roundCornerswithRadius:(float)cornerRadius
               andShadowOffset:(float)shadowOffset
{
    const float CORNER_RADIUS = cornerRadius;
    const float SHADOW_OFFSET = shadowOffset;
    const float SHADOW_OPACITY = 0.5;
    const float SHADOW_RADIUS = 3.0;

    UIView *superView = self.superview;

    CGRect oldBackgroundFrame = self.frame;
    [self removeFromSuperview];

    CGRect frameForShadowView = CGRectMake(0, 0, oldBackgroundFrame.size.width, oldBackgroundFrame.size.height);
    UIView *shadowView = [[UIView alloc] initWithFrame:frameForShadowView];
    [shadowView.layer setShadowOpacity:SHADOW_OPACITY];
    [shadowView.layer setShadowRadius:SHADOW_RADIUS];
    [shadowView.layer setShadowOffset:CGSizeMake(SHADOW_OFFSET, SHADOW_OFFSET)];

    [self.layer setCornerRadius:CORNER_RADIUS];
    [self.layer setMasksToBounds:YES];

    [shadowView addSubview:self];
    [superView addSubview:shadowView];

}