您应该在覆盖中更新掩码layoutSubviews
。随着约束条件的更新frame
的观点,layoutSubviews
被调用,所以这是更新掩码的正确位置。
顺便说一句,我不鼓励使用awakeFromNib
配置视图。如果您使用情节提要,它可以正常工作,但以编程方式创建的视图不会调用它。如果您确实想在创建视图时对其进行配置,最好将代码放在一些私有配置方法中,该方法由init(frame:)
and init(coder:)
。这样,它既适用于故事板,也适用于以编程方式创建的视图。
我还可能建议观察者观察可检查的属性,以触发圆角的更新。如果更改这些属性,您希望圆角自动更新。
Thus:
@IBDesignable
public class RoundedView: UIView {
@IBInspectable public var topLeft: Bool = false { didSet { setNeedsLayout() } }
@IBInspectable public var topRight: Bool = false { didSet { setNeedsLayout() } }
@IBInspectable public var bottomLeft: Bool = false { didSet { setNeedsLayout() } }
@IBInspectable public var bottomRight: Bool = false { didSet { setNeedsLayout() } }
@IBInspectable public var cornerRadius: CGFloat = 0 { didSet { setNeedsLayout() } }
public override func layoutSubviews() {
super.layoutSubviews()
var options = UIRectCorner()
if topLeft { options.formUnion(.topLeft) }
if topRight { options.formUnion(.topRight) }
if bottomLeft { options.formUnion(.bottomLeft) }
if bottomRight { options.formUnion(.bottomRight) }
let path = UIBezierPath(roundedRect: bounds,
byRoundingCorners: options,
cornerRadii: CGSize(width: cornerRadius, height: cornerRadius))
let maskLayer = CAShapeLayer()
maskLayer.path = path.cgPath
layer.mask = maskLayer
}
}
或者,如果针对 iOS 11 及更高版本,我们可以让 CoreAnimation 进行舍入:
@IBDesignable
public class RoundedView: UIView {
@IBInspectable public var topLeft: Bool = false { didSet { updateCorners() } }
@IBInspectable public var topRight: Bool = false { didSet { updateCorners() } }
@IBInspectable public var bottomLeft: Bool = false { didSet { updateCorners() } }
@IBInspectable public var bottomRight: Bool = false { didSet { updateCorners() } }
@IBInspectable public var cornerRadius: CGFloat = 0 { didSet { updateCorners() } }
public override init(frame: CGRect = .zero) {
super.init(frame: frame)
updateCorners()
}
required init?(coder aDecoder: NSCoder) {
super.init(coder: aDecoder)
updateCorners()
}
}
private extension RoundedView {
func updateCorners() {
var corners = CACornerMask()
if topLeft { corners.formUnion(.layerMinXMinYCorner) }
if topRight { corners.formUnion(.layerMaxXMinYCorner) }
if bottomLeft { corners.formUnion(.layerMinXMaxYCorner) }
if bottomRight { corners.formUnion(.layerMaxXMaxYCorner) }
layer.maskedCorners = corners
layer.cornerRadius = cornerRadius
}
}
后一种方法的好处是,如果我们碰巧要为frame
视图的:
如果您使用上述layoutSubviews
方法,那么你必须手动管理动画(例如使用CADisplayLink
).