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

button.layer.masksToBounds = false;

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;

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。

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;
}

iOS阴影和拐角半径

[iOS CALayer]

[iOS masksToBounds]

[iOS调试渲染]

你可以使用图层设置阴影

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从0到1 shadowRadius从0开始为正

不是简单的任务

请注意，阴影不是仅根据边界和边角raduis计算的。在创建阴影的过程中，需要考虑以下事项:

子视图层 子层 内容(支持图像)

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uisscreen .main.scale =当前屏幕的缩放因子

[iOS像素、点数、单位]

的绩效

使用层。角半径，阴影有一些性能影响

至于层。cornerRadius性能:

应用它的颜色混合使用[阅读更多]

至于影子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应该创建一个屏幕外视图，并基于这个信息创建一个阴影。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-缺乏活力。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)

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)
        }

    }
}