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。
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
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)
其他回答
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];
}
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]];
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。
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。
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];
}