下面的代码片段为UIView v添加了边框、边框半径和投影:

// border radius
[v.layer setCornerRadius:30.0f];

// border
[v.layer setBorderColor:[UIColor lightGrayColor].CGColor];
[v.layer setBorderWidth:1.5f];

// drop shadow
[v.layer setShadowColor:[UIColor blackColor].CGColor];
[v.layer setShadowOpacity:0.8];
[v.layer setShadowRadius:3.0];
[v.layer setShadowOffset:CGSizeMake(2.0, 2.0)];

Swift 5版本:

// border radius
v.layer.cornerRadius = 30.0

// border
v.layer.borderColor = UIColor.lightGray.cgColor
v.layer.borderWidth = 1.5

// drop shadow
v.layer.shadowColor = UIColor.black.cgColor
v.layer.shadowOpacity = 0.8
v.layer.shadowRadius = 3.0
v.layer.shadowOffset = CGSize(width: 2.0, height: 2.0)

您可以根据需要调整设置。

此外，将QuartzCore框架添加到您的项目中，并:

#import <QuartzCore/QuartzCore.h>

请看我关于masksToBounds的其他答案。

Note

这可能并不适用于所有情况。如果您发现此方法干扰您正在执行的其他绘图操作，请参阅此答案。

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];   
}    

使用Swift 4和Xcode 9，这是一个用投影和边框舍入ImageView的工作示例。

    //set dimensions and position of image (in this case, centered)
    let imageHeight: CGFloat = 150, imageWidth: CGFloat = 150
    let xPosition = (self.view.frame.width / 2) - (imageWidth / 2)
    let yPosition = (self.view.frame.height / 2) - (imageHeight / 2)

    //set desired corner radius
    let cornerRadius: CGFloat = 20

    //create container for the image
    let imageContainer = UIView(frame: CGRect(x: xPosition, y: yPosition, width: imageWidth, height: imageHeight))

    //configure the container
    imageContainer.clipsToBounds = false
    imageContainer.layer.shadowColor = UIColor.black.cgColor
    imageContainer.layer.shadowOpacity = 1
    imageContainer.layer.shadowOffset = CGSize(width: 3.0, height: 3.0)
    imageContainer.layer.shadowRadius = 5
    imageContainer.layer.shadowPath = UIBezierPath(roundedRect: imageContainer.bounds, cornerRadius: cornerRadius).cgPath

    //create imageView
    let imageView = UIImageView(frame: imageContainer.bounds)

    //configure the imageView
    imageView.clipsToBounds = true
    imageView.layer.cornerRadius = cornerRadius
    //add a border (if required)
    imageView.layer.borderColor = UIColor.black.cgColor
    imageView.layer.borderWidth = 1.0
    //set the image
    imageView.image = UIImage(named: "bird")

    //add the views to the superview
    view.addSubview(imageContainer)
    imageContainer.addSubview(imageView)

如果你想让图像是圆形的:(并且显示为无边框)

let cornerRadius = imageWidth / 2

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

button.layer.masksToBounds = false;

一种方法是将带有圆角的视图放到带有投影的视图中。

UIView* roundedView = [[UIView alloc] initWithFrame: frame];
roundedView.layer.cornerRadius = 5.0;
roundedView.layer.masksToBounds = YES;

UIView* shadowView = [[UIView alloc] initWithFrame: frame];
shadowView.layer.shadowColor = [UIColor blackColor].CGColor;
shadowView.layer.shadowRadius = 5.0;
shadowView.layer.shadowOffset = CGSizeMake(3.0, 3.0);
shadowView.layer.shadowOpacity = 1.0;
[shadowView addSubview: roundedView];

然后你可以在任何你想要的地方添加shadowView。