下面的代码片段为v(一个UIView)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>

关于masksToBounds，请参阅我的另一个答案。

请注意

这可能并不适用于所有情况。如果你发现这个方法干扰了你正在执行的其他绘图操作，请参阅这个答案。

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。

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];
}

如果你因为四舍五入的corners vs. subviews vs. masksToBounds而挣扎，那么尝试使用我的函数:

- (UIView*)putView:(UIView*)view insideShadowWithColor:(UIColor*)color andRadius:(CGFloat)shadowRadius andOffset:(CGSize)shadowOffset andOpacity:(CGFloat)shadowOpacity
{
CGRect shadowFrame; // Modify this if needed
shadowFrame.size.width = 0.f;
shadowFrame.size.height = 0.f;
shadowFrame.origin.x = 0.f;
shadowFrame.origin.y = 0.f;
UIView * shadow = [[UIView alloc] initWithFrame:shadowFrame];
shadow.userInteractionEnabled = NO; // Modify this if needed
shadow.layer.shadowColor = color.CGColor;
shadow.layer.shadowOffset = shadowOffset;
shadow.layer.shadowRadius = shadowRadius;
shadow.layer.masksToBounds = NO;
shadow.clipsToBounds = NO;
shadow.layer.shadowOpacity = shadowOpacity;
[view.superview insertSubview:shadow belowSubview:view];
[shadow addSubview:view];
return shadow;
}

在你的视图中调用它。无论你的视图是否有圆角，无论它的大小，它的形状-一个漂亮的阴影将被绘制出来。

只要保留函数的返回值，以便在想要删除表时引用它(或例如使用insertSubview:aboveView:)

当为容器视图分配阴影路径时，我使用以下技巧解决了这个问题:

[UIBezierPath bezierPathWithRoundedRect:cell.bounds cornerRadius:12]

请注意，阴影的路径是一个圆角矩形，与单元格包含的背景具有相同的角半径:

//this is the border for the UIView that is added to a cell
cell.backgroundView.layer.cornerRadius = 12;
cell.backgroundView.layer.masksToBounds = YES;
cell.backgroundView.layer.borderColor = [UIColor darkGrayColor].CGColor;
cell.backgroundView.layer.borderWidth = 1;


//this is the shadow around the cell itself (cannot have round corners with borders and shadow, need to use two views
cell.layer.shadowRadius = 2;
cell.layer.cornerRadius = 12;
cell.layer.masksToBounds = NO;
[[cell layer] setShadowColor:[[UIColor darkGrayColor] CGColor]];


[[cell layer] setShadowOffset:CGSizeMake(0.0,0.0)];
[[cell layer] setShadowOpacity:1.0];


UIBezierPath *path = [UIBezierPath bezierPathWithRoundedRect:cell.bounds cornerRadius:12];
[[cell layer] setShadowPath:[path CGPath]];

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，使它可以与按钮等一起使用。 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它的速度

+ (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;
}

Evan Mulawski提供的答案将会非常有效。问题是你必须将视图的背景色设置为clearColor，并将masksToBounds属性设置为NO。

你可以为视图设置任何你想要的颜色

v.layer.backgroundColor = your color;

希望这能有所帮助。

丹尼尔。Gindi上面的回答对我很有用!然而，我不得不做一些小的调整-改变shadowFrame的大小与视图的帧大小相同，并启用用户交互。以下是更新后的代码:

+ (UIView*)putView:(UIView*)view insideShadowWithColor:(UIColor*)color andRadius:(CGFloat)shadowRadius andOffset:(CGSize)shadowOffset andOpacity:(CGFloat)shadowOpacity
{
CGRect shadowFrame; // Modify this if needed


// Modified this line
shadowFrame.size = CGSizeMake(view.frame.size.width, view.frame.size.height);


shadowFrame.origin.x = 0.f;
shadowFrame.origin.y = 0.f;
UIView * shadow = [[UIView alloc] initWithFrame:shadowFrame];


// Modified this line
shadow.userInteractionEnabled = YES;
shadow.layer.shadowColor = color.CGColor;
shadow.layer.shadowOffset = shadowOffset;
shadow.layer.shadowRadius = shadowRadius;
shadow.layer.masksToBounds = NO;
shadow.clipsToBounds = NO;
shadow.layer.shadowOpacity = shadowOpacity;


[shadow addSubview:view];
return shadow;
}

我想补充的是，在我的情况下，我试图将此添加到第三方视图控制器，即我没有对代码的直接控制。下面是我如何使用上面的函数:

UIView *shadow = [self putView:vc.view
insideShadowWithColor:[UIColor blackColor]
andRadius:5.0
andOffset:CGSizeMake(0.0, 0.0)
andOpacity:1.0];
vc.view = shadow;
vc.view.layer.cornerRadius = 5.0;
vc.view.layer.masksToBounds = YES;

我对daniel.gindi的代码做了一些修改

这就是你要做的一切。

+ (void)putView:(UIView*)view insideShadowWithColor:(UIColor*)color andBlur:         (CGFloat)blur andOffset:(CGSize)shadowOffset andOpacity:(CGFloat)shadowOpacity
{
CGRect shadowFrame = view.frame;
UIView * shadow = [[UIView alloc] initWithFrame:shadowFrame];
shadow.backgroundColor = [UIColor redColor];
shadow.userInteractionEnabled = YES; // Modify this if needed
shadow.layer.shadowColor = color.CGColor;
shadow.layer.shadowOffset = shadowOffset;
shadow.layer.shadowRadius = blur;
shadow.layer.cornerRadius = view.layer.cornerRadius;
shadow.layer.masksToBounds = NO;
shadow.clipsToBounds = NO;
shadow.layer.shadowOpacity = shadowOpacity;
[view.superview insertSubview:shadow belowSubview:view];
}

这对我很管用。窍门是将背景颜色从主视图移到图层中。

CALayer *layer = view.layer;
layer.cornerRadius = 15.0f;
layer.masksToBounds = NO;


layer.shadowOffset = CGSizeMake(0, 3);
layer.shadowColor = [[UIColor blackColor] CGColor];
layer.shadowRadius = 2.0f;
layer.shadowOpacity = 0.35f;
layer.shadowPath = [[UIBezierPath bezierPathWithRoundedRect:layer.bounds cornerRadius:layer.cornerRadius] CGPath];


CGColorRef  bColor = view.backgroundColor.CGColor;
view.backgroundColor = nil;
layer.backgroundColor =  bColor ;

这里是masksToBounds冲突问题的解决方案，它适用于我。

在你设置corderRadius/borderColor/shadow等之后，将masksToBounds设置为NO:

v.layer.masksToBounds = NO;

你需要使用两个UIViews来实现这一点。一个UIView将像阴影一样工作，另一个将为圆形边界工作。

下面是Class Method在protocol的帮助下的代码片段:

@implementation UIMethods


+ (UIView *)genComposeButton:(UIViewController <UIComposeButtonDelegate> *)observer;
{
UIView *shadow = [[UIView alloc]init];
shadow.layer.cornerRadius = 5.0;
shadow.layer.shadowColor = [[UIColor blackColor] CGColor];
shadow.layer.shadowOpacity = 1.0;
shadow.layer.shadowRadius = 10.0;
shadow.layer.shadowOffset = CGSizeMake(0.0f, -0.5f);


UIButton *btnCompose = [[UIButton alloc]initWithFrame:CGRectMake(0, 0,60, 60)];
[btnCompose setUserInteractionEnabled:YES];
btnCompose.layer.cornerRadius = 30;
btnCompose.layer.masksToBounds = YES;
[btnCompose setImage:[UIImage imageNamed:@"60x60"] forState:UIControlStateNormal];
[btnCompose addTarget:observer action:@selector(btnCompose_click:) forControlEvents:UIControlEventTouchUpInside];
[shadow addSubview:btnCompose];
return shadow;
}

在上面的代码中，btnCompose_click:将成为一个@required委托方法，该方法将在单击按钮时触发。

在这里，我像这样在UIViewController中添加了一个按钮:

UIView *btnCompose = [UIMethods genComposeButton:self];
btnCompose.frame = CGRectMake(self.view.frame.size.width - 75,
self.view.frame.size.height - 75,
60, 60);
[self.view addSubview:btnCompose];

结果如下所示:

这就是你怎么做的，有圆角和圆角阴影，而不用担心路径。

//Inner view with content
[imageView.layer setBorderColor:[[UIColor lightGrayColor] CGColor]];
[imageView.layer setBorderWidth:1.0f];
[imageView.layer setCornerRadius:8.0f];
[imageView.layer setMasksToBounds:YES];


//Outer view with shadow
UIView* shadowContainer = [[UIView alloc] initWithFrame:imageView.frame];
[shadowContainer.layer setMasksToBounds:NO];
[shadowContainer.layer setShadowColor:[[UIColor blackColor] CGColor]];
[shadowContainer.layer setShadowOpacity:0.6f];
[shadowContainer.layer setShadowRadius:2.0f];
[shadowContainer.layer setShadowOffset: CGSizeMake(0.0f, 2.0f)];


[shadowContainer addSubview:imageView];

带有内容的视图，在我的例子中是UIImageView，有一个角半径，因此必须屏蔽到边界。

我们为阴影创建另一个同样大小的视图，设置它的maskToBounds为NO，然后将内容视图添加到容器视图(例如shadowContainer)。

阴影+边界+角半径

    scrollview.backgroundColor = [UIColor whiteColor];
CALayer *ScrlViewLayer = [scrollview layer];
[ScrlViewLayer setMasksToBounds:NO ];
[ScrlViewLayer setShadowColor:[[UIColor lightGrayColor] CGColor]];
[ScrlViewLayer setShadowOpacity:1.0 ];
[ScrlViewLayer setShadowRadius:6.0 ];
[ScrlViewLayer setShadowOffset:CGSizeMake( 0 , 0 )];
[ScrlViewLayer setShouldRasterize:YES];
[ScrlViewLayer setCornerRadius:5.0];
[ScrlViewLayer setBorderColor:[UIColor lightGrayColor].CGColor];
[ScrlViewLayer setBorderWidth:1.0];
[ScrlViewLayer setShadowPath:[UIBezierPath bezierPathWithRect:scrollview.bounds].CGPath];

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!

斯威夫特

// corner radius
blueView.layer.cornerRadius = 10


// border
blueView.layer.borderWidth = 1.0
blueView.layer.borderColor = UIColor.black.cgColor


// shadow
blueView.layer.shadowColor = UIColor.black.cgColor
blueView.layer.shadowOffset = CGSize(width: 3, height: 3)
blueView.layer.shadowOpacity = 0.7
blueView.layer.shadowRadius = 4.0

探索选择

问题1:阴影被剪掉了

如果我们希望将子层或子视图(如图像)的内容剪辑到视图的边界，该怎么办?

我们可以用

blueView.layer.masksToBounds = true

(或者，blueView.clipsToBounds = true给出相同的结果。)

但是，阴影也被剪掉了，因为它在边界之外!怎么办呢?怎么办呢?

解决方案

阴影和边界使用单独的视图。基本视图是透明的，并且有阴影。边界视图将它拥有的任何其他子内容剪辑到它的边界。

// add the shadow to the base view
baseView.backgroundColor = UIColor.clear
baseView.layer.shadowColor = UIColor.black.cgColor
baseView.layer.shadowOffset = CGSize(width: 3, height: 3)
baseView.layer.shadowOpacity = 0.7
baseView.layer.shadowRadius = 4.0


// add the border to subview
let borderView = UIView()
borderView.frame = baseView.bounds
borderView.layer.cornerRadius = 10
borderView.layer.borderColor = UIColor.black.cgColor
borderView.layer.borderWidth = 1.0
borderView.layer.masksToBounds = true
baseView.addSubview(borderView)


// add any other subcontent that you want clipped
let otherSubContent = UIImageView()
otherSubContent.image = UIImage(named: "lion")
otherSubContent.frame = borderView.bounds
borderView.addSubview(otherSubContent)

结果如下:

问题2:表现不佳

添加圆角和阴影可以提高性能。您可以通过为阴影使用预定义的路径并指定它是栅格化来提高性能。下面的代码可以添加到上面的示例中。

baseView.layer.shadowPath = UIBezierPath(roundedRect: baseView.bounds, cornerRadius: 10).cgPath
baseView.layer.shouldRasterize = true
baseView.layer.rasterizationScale = UIScreen.main.scale

更多细节参见这篇文章。也请参见在这里和在这里。

我们用Swift 4和Xcode 9测试了这个答案。

- (void)addShadowViewWithCornerRadius:(CGFloat)radius {


UIView *container = self.superview;


if (!container) {
return;
}


UIView *shadowView = [[UIView alloc] init];
shadowView.translatesAutoresizingMaskIntoConstraints = NO;
shadowView.backgroundColor = [UIColor lightGrayColor];
shadowView.layer.cornerRadius = radius;
shadowView.layer.masksToBounds = YES;


[container addSubview:shadowView];
[container bringSubviewToFront:shadowView];


[container addConstraint:[NSLayoutConstraint constraintWithItem:shadowView
attribute:NSLayoutAttributeWidth
relatedBy:NSLayoutRelationEqual
toItem:self
attribute:NSLayoutAttributeWidth
multiplier:1.0
constant:0.0]];
[container addConstraint:[NSLayoutConstraint constraintWithItem:shadowView
attribute:NSLayoutAttributeLeading
relatedBy:NSLayoutRelationEqual
toItem:self
attribute:NSLayoutAttributeLeading
multiplier:1.0
constant:2.0]];


[container addConstraint:[NSLayoutConstraint constraintWithItem:shadowView
attribute:NSLayoutAttributeHeight
relatedBy:NSLayoutRelationEqual
toItem:self
attribute:NSLayoutAttributeHeight
multiplier:1.0
constant:0.0]];
[container addConstraint:[NSLayoutConstraint constraintWithItem:shadowView
attribute:NSLayoutAttributeTop
relatedBy:NSLayoutRelationEqual
toItem:self
attribute:NSLayoutAttributeTop
multiplier:1.0
constant:2.0]];
[container sendSubviewToBack:shadowView];
}

此代码与其他代码示例的主要区别在于，它将阴影视图添加为兄弟视图(而不是将当前视图添加为阴影视图的子视图)，从而消除了以任何方式修改现有视图层次结构的需要。

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。这是完整的证明解决方案。

- (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;
}

检查GitHub上的示例项目以确保正确使用了该组件。

简单的Swift 5解决方案，没有任何额外的子视图或子类化:

extension UIView {


func addShadow(offset: CGSize, color: UIColor, radius: CGFloat, opacity: Float) {
layer.masksToBounds = false
layer.shadowOffset = offset
layer.shadowColor = color.cgColor
layer.shadowRadius = radius
layer.shadowOpacity = opacity


let backgroundCGColor = backgroundColor?.cgColor
backgroundColor = nil
layer.backgroundColor =  backgroundCGColor
}
}

注意，你应该用圆角半径和其他属性在调用之前 addShadow来设置你的视图。

之后，像这样从viewDidLoad调用它:

button.addShadow(offset: CGSize.init(width: 0, height: 3), color: UIColor.black, radius: 2.0, opacity: 0.35)

最终结果:

超级简单!

我写了这个UIView分类方法来解决这个问题，使用单独的视图来表示阴影和角的半径。

-(UIView *)shadowedWrapViewWithBounds:(CGRect)bounds {
UIView *baseView = [[UIView alloc] init];
baseView.bounds = bounds;
baseView.backgroundColor = [UIColor clearColor];
baseView.layer.shadowColor = [UIColor blackColor].CGColor;
baseView.layer.shadowOffset = CGSizeMake(0, 0);
baseView.layer.shadowOpacity = 0.7;
baseView.layer.shadowRadius = 4.0;


// improve performance
baseView.layer.shadowPath = [UIBezierPath bezierPathWithRoundedRect:baseView.bounds cornerRadius:4].CGPath;
baseView.layer.shouldRasterize = YES;
baseView.layer.rasterizationScale = [UIScreen mainScreen].scale;


[baseView addSubview:self];
//use Masonry autolayout, self can set corner radius
[self makeConstraints:^(MASConstraintMaker *make) {
make.edges.equalTo(baseView);
}];


return baseView;
}

你需要使用shadowView和roundView

shadowView

• 必须有背景色
• 应该放在roundView后面
• 诀窍是将shadowView布局在内部一点，并且它的阴影需要发光。调整insets，使shadowView在roundView后面完全不可见

roundView

• 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

首先，创建一个UIView扩展:

//
//  UIView-Extension.swift
//


import Foundation
import UIKit


@IBDesignable
extension UIView {
// Shadow
@IBInspectable var shadow: Bool {
get {
return layer.shadowOpacity > 0.0
}
set {
if newValue == true {
self.addShadow()
}
}
}


fileprivate func addShadow(shadowColor: CGColor = UIColor.black.cgColor, shadowOffset: CGSize = CGSize(width: 3.0, height: 3.0), shadowOpacity: Float = 0.35, shadowRadius: CGFloat = 5.0) {
let layer = self.layer
layer.masksToBounds = false


layer.shadowColor = shadowColor
layer.shadowOffset = shadowOffset
layer.shadowRadius = shadowRadius
layer.shadowOpacity = shadowOpacity
layer.shadowPath = UIBezierPath(roundedRect: layer.bounds, cornerRadius: layer.cornerRadius).cgPath


let backgroundColor = self.backgroundColor?.cgColor
self.backgroundColor = nil
layer.backgroundColor =  backgroundColor
}




// Corner radius
@IBInspectable var circle: Bool {
get {
return layer.cornerRadius == self.bounds.width*0.5
}
set {
if newValue == true {
self.cornerRadius = self.bounds.width*0.5
}
}
}


@IBInspectable var cornerRadius: CGFloat {
get {
return self.layer.cornerRadius
}


set {
self.layer.cornerRadius = newValue
}
}




// Borders
// Border width
@IBInspectable
public var borderWidth: CGFloat {
set {
layer.borderWidth = newValue
}


get {
return layer.borderWidth
}
}


// Border color
@IBInspectable
public var borderColor: UIColor? {
set {
layer.borderColor = newValue?.cgColor
}


get {
if let borderColor = layer.borderColor {
return UIColor(cgColor: borderColor)
}
return nil
}
}
}

然后，在界面构建器中选择你的UIView，设置蒙上阴影。和刀尖圆弧半径，如下所示:

< / >

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

button.layer.masksToBounds = false;

创建UIView的子类

class ShadowView: UIView {


required init?(coder aDecoder: NSCoder) {
super.init(coder: aDecoder)


// corner radius
self.layer.cornerRadius = 10


// border
self.layer.borderWidth = 1.0
self.layer.borderColor = UIColor.black.cgColor


// shadow
self.layer.shadowColor = UIColor.black.cgColor
self.layer.shadowOffset = CGSize(width: 3, height: 3)
self.layer.shadowOpacity = 0.7
self.layer.shadowRadius = 4.0
}


}

使用. .

斯威夫特4使UICollectionViewCell 轮和添加阴影的解决方案，没有任何扩展和并发症:)

如果同时有一个仍然 苦苦挣扎的到轮的角和添加 阴影。虽然这个解决方案适用于UICollectionViewCell，但它可以推广到任何视图。

这个技巧对我来说很有效，不需要做任何扩展和所有复杂的事情。我正在使用storyBoard。

技术

连接containerView的出口。在CellforItemAtIndexPath委托函数中添加以下代码行。

//adds shadow to the layer of cell


cell.layer.cornerRadius = 3.0
cell.layer.masksToBounds = false
cell.layer.shadowColor = UIColor.black.cgColor
cell.layer.shadowOffset = CGSize(width: 0, height: 0)
cell.layer.shadowOpacity = 0.6


//makes the cell round


let containerView = cell.containerView!
containerView.layer.cornerRadius = 8
containerView.clipsToBounds = true

输出

查看模拟器截图

在swift 4中进行了测试

import UIKit


extension UIView {
@IBInspectable var dropShadow: Bool {
set{
if newValue {
layer.shadowColor = UIColor.black.cgColor
layer.shadowOpacity = 0.4
layer.shadowRadius = 1
layer.shadowOffset = CGSize.zero
} else {
layer.shadowColor = UIColor.clear.cgColor
layer.shadowOpacity = 0
layer.shadowRadius = 0
layer.shadowOffset = CGSize.zero
}
}
get {
return layer.shadowOpacity > 0
}
}
}

生产

如果你像这样在检查器中启用它:

它将添加用户定义的运行时属性，结果是:

(我之前添加了cornerRadius = 8)

：）

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

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)
}


}
}

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)
}
}

这里有一个肯定有效的解决方案!

我已经创建了UIView扩展所需的边应用阴影如下

enum AIEdge:Int {
case
Top,
Left,
Bottom,
Right,
Top_Left,
Top_Right,
Bottom_Left,
Bottom_Right,
All,
None
}


extension UIView {
        

func applyShadowWithCornerRadius(color:UIColor, opacity:Float, radius: CGFloat, edge:AIEdge, shadowSpace:CGFloat, cornerRadius: CGFloat)    {


var sizeOffset:CGSize = CGSize.zero
        

switch edge {
case .Top:
sizeOffset = CGSize(width: 0, height: -shadowSpace)
case .Left:
sizeOffset = CGSize(width: -shadowSpace, height: 0)
case .Bottom:
sizeOffset = CGSize(width: 0, height: shadowSpace)
case .Right:
sizeOffset = CGSize(width: shadowSpace, height: 0)
            

            

case .Top_Left:
sizeOffset = CGSize(width: -shadowSpace, height: -shadowSpace)
case .Top_Right:
sizeOffset = CGSize(width: shadowSpace, height: -shadowSpace)
case .Bottom_Left:
sizeOffset = CGSize(width: -shadowSpace, height: shadowSpace)
case .Bottom_Right:
sizeOffset = CGSize(width: shadowSpace, height: shadowSpace)
            

            

case .All:
sizeOffset = CGSize(width: 0, height: 0)
case .None:
sizeOffset = CGSize.zero
}


self.layer.cornerRadius = cornerRadius
self.layer.masksToBounds = true


self.layer.shadowColor = color.cgColor
self.layer.shadowOpacity = opacity
self.layer.shadowOffset = sizeOffset
self.layer.shadowRadius = radius
self.layer.masksToBounds = false


self.layer.shadowPath = UIBezierPath(roundedRect:self.bounds, cornerRadius:self.layer.cornerRadius).cgPath
}
}

最后，你可以为你的UIView子类调用下面的阴影函数，你也可以指定边缘上应用阴影，尝试不同的变化根据你需要改变下面方法调用的参数。

viewRoundedToBeShadowedAsWell.applyShadowWithCornerRadius(color: .gray, opacity: 1, radius: 15, edge: AIEdge.All, shadowSpace: 15)

注意:如果仍然不工作，试着从主线程调用它

DispatchQueue.main.async {
viewRoundedToBeShadowedAsWell.applyShadowWithCornerRadius(color: .gray, opacity: 1, radius: 15, edge: AIEdge.All, shadowSpace: 15)
}

希望有人觉得这有用!

以下是结果图片:

var shadows = UIView()
shadows.frame = view.frame
shadows.clipsToBounds = false
view.addSubview(shadows)




let shadowPath0 = UIBezierPath(roundedRect: shadows.bounds, cornerRadius: 10)
let layer0 = CALayer()
layer0.shadowPath = shadowPath0.cgPath
layer0.shadowColor = UIColor(red: 0, green: 0, blue: 0, alpha: 0.23).cgColor
layer0.shadowOpacity = 1
layer0.shadowRadius = 6
layer0.shadowOffset = CGSize(width: 0, height: 3)
layer0.bounds = shadows.bounds
layer0.position = shadows.center


shadows.layer.addSublayer(layer0)

iOS阴影和拐角半径

[iOS CALayer]

[iOS masksToBounds] . > .

[iOS调试渲染]

你可以使用layer来设置shadow

view1.layer.shadowColor = UIColor.magenta.cgColor


view1.layer.shadowOffset = CGSize(width: 0, height: 0)
view1.layer.shadowOpacity = 1
view1.layer.shadowRadius = 0

可视化

1. shadowoffset。宽度,2. shadowoffset。高度,3。shadowOpacity 4。shadowRadius

• shadowOffset宽度和高度是任意的
• shadowOpacity是从0到1
• shadowRadius从0开始为正

不是简单的任务

请注意，阴影的不仅基于boundaries和cornerRaduis计算。在创建阴影的过程中，需要考虑以下事项:

• 子视图层
• 子层
• content (Backing Image)

view1.backgroundColor = .clear
view1.layer.contents = UIImage(named: "ring")?.cgImage
view1.layer.contentsScale = UIScreen.main.scale

ScaleFactor(contentsScale， rasterizationScale) -默认为1.0

currentBitmapSize = layerSize * scaleFactor


//non retina
1 point == 1x pixels


//Retina
1 point == 2x pixels
//or
1 point == 3x pixels


//For example to draw line
point(width: 4, height: 2) == 1x pixels(width: 4, height: 2)(8 pixels) == 2x pixels(width: 8, height: 4)(32 pixels)

使用UIScreen.main.scale =当前屏幕的缩放因子

[iOS像素vs点数vs单位]

的绩效

使用layer.cornerRadius， shadow会有一些性能影响

至于layer.cornerRadius的性能:

应用它color blending使用(了解更多)

至于shadow, Xcode提示你:

The layer is using dynamic shadows which are expensive to render. If possible try setting shadowPath, or pre-rendering the shadow into an image and putting it under the layer

1. 另外，使用shadowPath

用于内部静态层。默认情况下，它是nil，这就是为什么UIKit应该创建视图离屏，并基于此信息创建一个阴影。这就是为什么您能够预定义路径并进行设置。另一个优点是，您可以根据需要创建自定义阴影

view1.layer.shadowPath = UIBezierPath(roundedRect: view1.bounds, cornerRadius: 50).cgPath

缺点 -不是动态的。如果视图改变边界(宽度，高度，角半径…)，阴影仍然是它是(旧的边界)。如果视图的位置被改变(移动，滚动)shadowPath将是正确的

2. 缓存栅格化

[iOS shouldRasterize]

如果你特别想为UIButtons自定义圆角，有很多不同的方法来实现。

下面的代码示例(感谢艾丽卡)很好地概述了所有的可能性。

iOS 15之前的圆角按钮

在iOS 15之前，你可以通过设置layer.cornerRadius， backgroundColor和setTitleColor来创建圆角按钮。

let button = UIButton(type: .system)
button.setTitle("Button", for: .normal)
button.setTitleColor(.white, for: .normal)
button.backgroundColor = .systemPink
button.layer.cornerRadius = 8


button.contentEdgeInsets = UIEdgeInsets(
top: 10,
left: 20,
bottom: 10,
right: 20
)

胶囊按钮

如果我们增加足够大的角半径值，您可以创建一个胶囊风格的按钮。为了创建一个胶囊风格的按钮，我们设置角半径等于按钮高度的一半。由于按钮的高度可能会根据标题大小或布局而变化，我通常为胶囊样式创建一个UIButton子类。

class CapsuleButton: UIButton {
override func layoutSubviews() {
super.layoutSubviews()
let height = bounds.height
layer.cornerRadius = height/2
}
}


let capsule = CapsuleButton(type: .system)
capsule.setTitle("Button", for: .normal)
capsule.setTitleColor(.white, for: .normal)
capsule.backgroundColor = .systemPink
capsule.contentEdgeInsets = UIEdgeInsets(
top: 10,
left: 20,
bottom: 10,
right: 20
)

光滑的角落

如果你想复制Apple平滑角，你也可以用cornerCurve属性来做。要创建连续的平滑角，请设置图层。拐角按钮到.continuous的曲线。

let button = UIButton(type: .system)
button.setTitle("Button", for: .normal)
button.setTitleColor(.white, for: .normal)
button.backgroundColor = .systemPink
button.layer.cornerRadius = 8
button.layer.cornerCurve = .continuous


button.contentEdgeInsets = UIEdgeInsets(
top: 10,
left: 20,
bottom: 10,
right: 20
)

圆角按钮在iOS 15使用UIButton。配置

在iOS 15中，苹果引入了一种通过UIButton.Configuration自定义按钮的新方法。

var configuration = UIButton.Configuration.filled()


configuration.title = "Button"
configuration.baseBackgroundColor = UIColor.systemPink
configuration.contentInsets = NSDirectionalEdgeInsets(
top: 10,
leading: 20,
bottom: 10,
trailing: 20
)


let button = UIButton(configuration: configuration, primaryAction: nil)

使用cornerStyle控制角的半径

UIButton.Configuration有许多内置的角落样式供你选择。你可以用cornerStyle属性来设置。

configuration.cornerStyle = .small
configuration.cornerStyle = .medium
configuration.cornerStyle = .large
configuration.cornerStyle = .capsule

自定义角半径

如果你想要更独特的东西，你可以通过UIBackgroundConfiguration的cornerRadius指定角半径。

var configuration = UIButton.Configuration.filled()
configuration.title = "Button"
configuration.baseBackgroundColor = UIColor.systemPink
configuration.contentInsets = NSDirectionalEdgeInsets(
top: 10,
leading: 20,
bottom: 10,
trailing: 20
)
configuration.background.cornerRadius = 20


configuration.cornerStyle = .fixed




let button = UIButton(configuration: configuration, primaryAction: nil)