我在一个应用程序上工作了几年，收到了一个简单的设计请求:在UIView上圆角并添加投影。做以下所给的事
我想要一个自定义的UIView…:我只是想要一个空白的白色视图与圆角和光滴阴影(没有照明效果)。我可以逐个执行这些操作，但通常会发生clipToBounds/maskToBounds冲突。
当前回答
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
(另外,blueView。clipsToBounds = true给出相同的结果。)
但是，哦不!影子也被剪掉了，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
更多细节请看这篇文章。看这里和这里。
我们用Swift 4和Xcode 9测试了这个答案。
其他回答
下面的方法最适合我 (这段代码位于UIView扩展中，因此self表示一些我们必须添加阴影和圆角的UIView)
- (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之间的主要区别在于，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。
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)
}
}
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
(另外,blueView。clipsToBounds = true给出相同的结果。)
但是，哦不!影子也被剪掉了，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
更多细节请看这篇文章。看这里和这里。
我们用Swift 4和Xcode 9测试了这个答案。
你需要使用两个uiview来实现这一点。一个UIView会像阴影一样工作，另一个会为圆角边界工作。
下面是一个在协议帮助下的类方法的代码片段:
@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。
在这里我添加了一个按钮到我的UIViewController，像这样:
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:
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];
}
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