你需要添加masksToBounds = true的组合之间的corderRadius shadowRadius。

button.layer.masksToBounds = false;

在研究了一整天的圆角视图与阴影之后，我很高兴在这里发布我的自定义uiview类，希望结束这个问题:

RoundCornerShadowView.h

#import <UIKit/UIKit.h>

@interface RoundCornerShadowView : UIView

@end

RoundCornerShadowView.m

#import "RoundCornerShadowView.h"

@implementation RoundCornerShadowView

// *** must override this method, not the other method ***
// otherwise, the background corner doesn't disappear....
// @2015/05/29
-(void) layoutSubviews {
    [super layoutSubviews];//is must to ensure rightly layout children view

    //1. first, create Inner layer with content
    CALayer *innerView = [CALayer layer];
    innerView.frame = CGRectMake(0,0,self.bounds.size.width,self.bounds.size.height);
    //instead of: innerView.frame = self.frame;
    innerView.borderWidth = 1.0f;
    innerView.cornerRadius = 6.0f;
    innerView.masksToBounds = YES;
    innerView.borderColor = [[UIColor lightGrayColor] CGColor];
    innerView.backgroundColor = [[UIColor whiteColor] CGColor];
    //put the layer to the BOTTOM of layers is also a MUST step...
    //otherwise this layer will overlay the sub uiviews in current uiview...
    [self.layer insertSublayer:innerView atIndex:0];

    //2. then, create shadow with self layer
    self.layer.masksToBounds = NO;
    self.layer.shadowColor = [[UIColor darkGrayColor] CGColor];
    self.layer.shadowOpacity = 0.4f;
    //shadow length
    self.layer.shadowRadius = 2.0f;
    //no offset
    self.layer.shadowOffset = CGSizeMake(0, 0);
    //right down shadow
    //[self.layer setShadowOffset: CGSizeMake(1.0f, 1.0f)];

    //3. last but important, MUST clear current view background color, or the color will show in the corner!
    self.backgroundColor = [UIColor clearColor];
}

@end

所以，不需要在视图中添加子视图或在目标视图中添加子视图，只需在当前视图中添加一层，并执行3步即可完成!

仔细查看代码中的注释，这有助于理解组件!

import UIKit

extension UIView {

    func addShadow(shadowColor: UIColor, offSet: CGSize, opacity: Float, shadowRadius: CGFloat, cornerRadius: CGFloat, corners: UIRectCorner, fillColor: UIColor = .white) {

        let shadowLayer = CAShapeLayer()
        let size = CGSize(width: cornerRadius, height: cornerRadius)
        let cgPath = UIBezierPath(roundedRect: self.bounds, byRoundingCorners: corners, cornerRadii: size).cgPath //1
        shadowLayer.path = cgPath //2
        shadowLayer.fillColor = fillColor.cgColor //3
        shadowLayer.shadowColor = shadowColor.cgColor //4
        shadowLayer.shadowPath = cgPath
        shadowLayer.shadowOffset = offSet //5
        shadowLayer.shadowOpacity = opacity
        shadowLayer.shadowRadius = shadowRadius
        self.layer.addSublayer(shadowLayer)
    }
}

如果你不想像David c建议的那样改变你的nibs和视图层次结构，这个方法可以帮你。为你的UIImageView添加圆角和阴影只需使用这个方法，例如:

[Utils roundCornersForImageView:myImageView withCornerRadius:6.0 
andShadowOffset:2.0];

(!)出于性能原因，我不认为在像UITableView这样的东西中使用这段代码是个好主意，因为这段代码改变了视图层次结构。所以我会建议改变你的nib，并添加一个容器视图的阴影效果和使用戴维C.代码。

+ (void)roundCornersForImageView:(UIImageView *)imageView 
withCornerRadius:(float)cornerRadius andShadowOffset:(float)shadowOffset
{
    const float CORNER_RADIUS = cornerRadius;
    const float BORDER_WIDTH = 1.0; 
    const float SHADOW_OFFSET = shadowOffset;
    const float SHADOW_OPACITY = 0.8;
    const float SHADOW_RADIUS = 3.0;

    //Our old image now is just background image view with shadow
    UIImageView *backgroundImageView = imageView;
    UIView *superView = backgroundImageView.superview;

    //Make wider actual visible rect taking into account shadow
    //offset
    CGRect oldBackgroundFrame = backgroundImageView.frame;
    CGRect newBackgroundFrame = CGRectMake(oldBackgroundFrame.origin.x, oldBackgroundFrame.origin.y, oldBackgroundFrame.size.width + SHADOW_OFFSET, oldBackgroundFrame.size.height + SHADOW_OFFSET);
    [backgroundImageView removeFromSuperview];
    backgroundImageView.frame = newBackgroundFrame;        

    //Make new UIImageView with rounded corners and put our old image
    CGRect frameForRoundedImageView = CGRectMake(0, 0, oldBackgroundFrame.size.width, oldBackgroundFrame.size.height);
    UIImageView *roundedImageView = [[UIImageView alloc]initWithFrame:frameForRoundedImageView];
    roundedImageView.image = imageView.image;
    [roundedImageView.layer setCornerRadius:CORNER_RADIUS];
    [roundedImageView.layer setBorderColor:[UIColor lightGrayColor].CGColor];        
    [roundedImageView.layer setBorderWidth:BORDER_WIDTH]; 
    [roundedImageView.layer setMasksToBounds:YES];

    //Set shadow preferences
    [backgroundImageView setImage:nil];
    [backgroundImageView.layer setShadowColor:[UIColor blackColor].CGColor];
    [backgroundImageView.layer setShadowOpacity:SHADOW_OPACITY];
    [backgroundImageView.layer setShadowRadius:SHADOW_RADIUS];
    [backgroundImageView.layer setShadowOffset:CGSizeMake(SHADOW_OFFSET, SHADOW_OFFSET)];   

    //Add out two image views back to the view hierarchy.
    [backgroundImageView addSubview:roundedImageView];
    [superView addSubview:backgroundImageView];   
}    

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];

}

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;
}