有没有办法为一个UIView的左上角和右上角设置角半径?
我尝试了下面的方法,但最终它再也看不到视图了。
UIView *view = [[UIView alloc] initWithFrame:frame];
CALayer *layer = [CALayer layer];
UIBezierPath *shadowPath = [UIBezierPath bezierPathWithRoundedRect:frame byRoundingCorners:(UIRectCornerTopLeft|UIRectCornerTopRight) cornerRadii:CGSizeMake(3.0, 3.0)];
layer.shadowPath = shadowPath.CGPath;
view.layer.mask = layer;
下面是@JohnnyRockex的Swift版本的回答
extension UIView {
func roundCorners(_ corners: UIRectCorner, radius: CGFloat) {
let path = UIBezierPath(roundedRect: self.bounds, byRoundingCorners: corners, cornerRadii: CGSize(width: radius, height: radius))
let mask = CAShapeLayer()
mask.path = path.cgPath
self.layer.mask = mask
}
}
view.roundCorners([.topLeft, .bottomRight], radius: 10)
Note
如果你正在使用自动布局,你需要子类化你的UIView,并在视图的layoutSubviews中调用roundCorners以获得最佳效果。
class View: UIView {
override func layoutSubviews() {
super.layoutSubviews()
self.roundCorners([.topLeft, .bottomLeft], radius: 10)
}
}
注意,如果你有布局约束附加到它,你必须在你的UIView子类中按如下方式刷新它:
override func layoutSubviews() {
super.layoutSubviews()
roundCorners(corners: [.topLeft, .topRight], radius: 3.0)
}
如果你不这样做,它就不会出现。
和圆角,使用扩展:
extension UIView {
func roundCorners(corners: UIRectCorner, radius: CGFloat) {
let path = UIBezierPath(roundedRect: bounds, byRoundingCorners: corners, cornerRadii: CGSize(width: radius, height: radius))
let mask = CAShapeLayer()
mask.path = path.cgPath
layer.mask = mask
}
}
附加的视图控制器情况:无论你不能或不想子类化一个视图,你仍然可以舍入一个视图。通过覆盖viewWillLayoutSubviews()函数,从它的视图控制器中完成,如下所示:
class MyVC: UIViewController {
/// The view to round the top-left and top-right hand corners
let theView: UIView = {
let v = UIView(frame: CGRect(x: 10, y: 10, width: 200, height: 200))
v.backgroundColor = .red
return v
}()
override func loadView() {
super.loadView()
view.addSubview(theView)
}
override func viewWillLayoutSubviews() {
super.viewWillLayoutSubviews()
// Call the roundCorners() func right there.
theView.roundCorners(corners: [.topLeft, .topRight], radius: 30)
}
}
简单的扩展
extension UIView {
func roundCorners(corners: UIRectCorner, radius: CGFloat) {
if #available(iOS 11, *) {
self.clipsToBounds = true
self.layer.cornerRadius = radius
var masked = CACornerMask()
if corners.contains(.topLeft) { masked.insert(.layerMinXMinYCorner) }
if corners.contains(.topRight) { masked.insert(.layerMaxXMinYCorner) }
if corners.contains(.bottomLeft) { masked.insert(.layerMinXMaxYCorner) }
if corners.contains(.bottomRight) { masked.insert(.layerMaxXMaxYCorner) }
self.layer.maskedCorners = masked
}
else {
let path = UIBezierPath(roundedRect: bounds, byRoundingCorners: corners, cornerRadii: CGSize(width: radius, height: radius))
let mask = CAShapeLayer()
mask.path = path.cgPath
layer.mask = mask
}
}
}
用法:
view.roundCorners(corners: [.bottomLeft, .bottomRight], radius: 12)
在Swift 4.2中,通过@IBDesignable创建它,如下所示:
@IBDesignable
class DesignableViewCustomCorner: UIView {
@IBInspectable var cornerRadious: CGFloat = 0 {
didSet {
let path = UIBezierPath(roundedRect: self.bounds, byRoundingCorners: [.topLeft, .topRight], cornerRadii: CGSize(width: cornerRadious, height: cornerRadious))
let mask = CAShapeLayer()
mask.path = path.cgPath
self.layer.mask = mask
}
}
}