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
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。
如果你因为圆角、子视图和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，这样当你想要删除表时就可以引用它(或者例如使用insertSubview:aboveView:)
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)
}
}
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。
推荐文章
- 如何删除默认的导航栏空间在SwiftUI导航视图
- 如何在iOS中使用Swift编程segue
- Swift -整数转换为小时/分钟/秒
- Swift:声明一个空字典
- 在成功提交我的应用程序后，“太多符号文件”
- 首先添加一个UIView，甚至是导航栏
- 我如何改变UIButton标题颜色?
- 如何从UIImage (Cocoa Touch)或CGImage (Core Graphics)获取像素数据?
- 在Swift中如何调用GCD主线程上的参数方法?
- NSLayoutConstraints是可动画的吗?
- iOS -构建失败，CocoaPods无法找到头文件
- CFNetwork SSLHandshake iOS 9失败
- 请求失败:不可接受的内容类型:文本/html使用AFNetworking 2.0
- 缺少推荐的图标文件-该包不包含iPhone / iPod Touch的应用程序图标，像素为“120x120”，png格式
- 以编程方式创建segue
