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;
当前回答
下面是一个实现的简短方法:
- (void)viewDidLoad {
[super viewDidLoad];
UIButton *openInMaps = [UIButton new];
[openInMaps setFrame:CGRectMake(15, 135, 114, 70)];
openInMaps = (UIButton *)[self roundCornersOnView:openInMaps onTopLeft:NO topRight:NO bottomLeft:YES bottomRight:NO radius:5.0];
}
- (UIView *)roundCornersOnView:(UIView *)view onTopLeft:(BOOL)tl topRight:(BOOL)tr bottomLeft:(BOOL)bl bottomRight:(BOOL)br radius:(float)radius {
if (tl || tr || bl || br) {
UIRectCorner corner = 0;
if (tl) {corner = corner | UIRectCornerTopLeft;}
if (tr) {corner = corner | UIRectCornerTopRight;}
if (bl) {corner = corner | UIRectCornerBottomLeft;}
if (br) {corner = corner | UIRectCornerBottomRight;}
UIView *roundedView = view;
UIBezierPath *maskPath = [UIBezierPath bezierPathWithRoundedRect:roundedView.bounds byRoundingCorners:corner cornerRadii:CGSizeMake(radius, radius)];
CAShapeLayer *maskLayer = [CAShapeLayer layer];
maskLayer.frame = roundedView.bounds;
maskLayer.path = maskPath.CGPath;
roundedView.layer.mask = maskLayer;
return roundedView;
}
return view;
}
其他回答
如果你正在寻找一个界面构建器的唯一解决方案，有一个适用于iOS 11或更高版本。在这里可以看到我的答案:https://stackoverflow.com/a/58626264
对于 SwiftUI
我找到了这些解决方案，你可以在这里查看https://stackoverflow.com/a/56763282/3716103
我强烈推荐第一个
选项1:使用Path + GeometryReader
(更多关于GeometryReader的信息:https://swiftui-lab.com/geometryreader-to-the-rescue/)
struct ContentView : View {
var body: some View {
Text("Hello World!")
.foregroundColor(.white)
.font(.largeTitle)
.padding(20)
.background(RoundedCorners(color: .blue, tl: 0, tr: 30, bl: 30, br: 0))
}
}
RoundedCorners
struct RoundedCorners: View {
var color: Color = .white
var tl: CGFloat = 0.0
var tr: CGFloat = 0.0
var bl: CGFloat = 0.0
var br: CGFloat = 0.0
var body: some View {
GeometryReader { geometry in
Path { path in
let w = geometry.size.width
let h = geometry.size.height
// Make sure we do not exceed the size of the rectangle
let tr = min(min(self.tr, h/2), w/2)
let tl = min(min(self.tl, h/2), w/2)
let bl = min(min(self.bl, h/2), w/2)
let br = min(min(self.br, h/2), w/2)
path.move(to: CGPoint(x: w / 2.0, y: 0))
path.addLine(to: CGPoint(x: w - tr, y: 0))
path.addArc(center: CGPoint(x: w - tr, y: tr), radius: tr, startAngle: Angle(degrees: -90), endAngle: Angle(degrees: 0), clockwise: false)
path.addLine(to: CGPoint(x: w, y: h - be))
path.addArc(center: CGPoint(x: w - br, y: h - br), radius: br, startAngle: Angle(degrees: 0), endAngle: Angle(degrees: 90), clockwise: false)
path.addLine(to: CGPoint(x: bl, y: h))
path.addArc(center: CGPoint(x: bl, y: h - bl), radius: bl, startAngle: Angle(degrees: 90), endAngle: Angle(degrees: 180), clockwise: false)
path.addLine(to: CGPoint(x: 0, y: tl))
path.addArc(center: CGPoint(x: tl, y: tl), radius: tl, startAngle: Angle(degrees: 180), endAngle: Angle(degrees: 270), clockwise: false)
}
.fill(self.color)
}
}
}
RoundedCorners_Previews
struct RoundedCorners_Previews: PreviewProvider {
static var previews: some View {
RoundedCorners(color: .pink, tl: 40, tr: 40, bl: 40, br: 40)
}
}
iOS 11, Swift 4 你可以试试这段代码:
if #available(iOS 11.0, *) {
element.clipsToBounds = true
element.layer.cornerRadius = CORNER_RADIUS
element.layer.maskedCorners = [.layerMaxXMaxYCorner]
} else {
// Fallback on earlier versions
}
你可以在表格视图单元格中使用这个。
所有已经给出的答案都是非常好的和有效的(特别是尤努斯使用蒙版属性的想法)。
然而，我需要一些更复杂的东西，因为我的层可以经常改变大小，这意味着我需要每次都调用掩蔽逻辑，这有点烦人。
我使用了swift扩展和计算属性来构建一个真正的cornerRadii属性，它负责在图层布局时自动更新蒙版。
这是使用Peter Steinberg伟大的Aspects库实现的。
完整代码在这里:
extension CALayer {
// This will hold the keys for the runtime property associations
private struct AssociationKey {
static var CornerRect:Int8 = 1 // for the UIRectCorner argument
static var CornerRadius:Int8 = 2 // for the radius argument
}
// new computed property on CALayer
// You send the corners you want to round (ex. [.TopLeft, .BottomLeft])
// and the radius at which you want the corners to be round
var cornerRadii:(corners: UIRectCorner, radius:CGFloat) {
get {
let number = objc_getAssociatedObject(self, &AssociationKey.CornerRect) as? NSNumber ?? 0
let radius = objc_getAssociatedObject(self, &AssociationKey.CornerRadius) as? NSNumber ?? 0
return (corners: UIRectCorner(rawValue: number.unsignedLongValue), radius: CGFloat(radius.floatValue))
}
set (v) {
let radius = v.radius
let closure:((Void)->Void) = {
let path = UIBezierPath(roundedRect: self.bounds, byRoundingCorners: v.corners, cornerRadii: CGSize(width: radius, height: radius))
let mask = CAShapeLayer()
mask.path = path.CGPath
self.mask = mask
}
let block: @convention(block) Void -> Void = closure
let objectBlock = unsafeBitCast(block, AnyObject.self)
objc_setAssociatedObject(self, &AssociationKey.CornerRect, NSNumber(unsignedLong: v.corners.rawValue), .OBJC_ASSOCIATION_RETAIN)
objc_setAssociatedObject(self, &AssociationKey.CornerRadius, NSNumber(float: Float(v.radius)), .OBJC_ASSOCIATION_RETAIN)
do { try aspect_hookSelector("layoutSublayers", withOptions: .PositionAfter, usingBlock: objectBlock) }
catch _ { }
}
}
}
我写了一篇简单的博客来解释这一点。
下面是一个实现的简短方法:
- (void)viewDidLoad {
[super viewDidLoad];
UIButton *openInMaps = [UIButton new];
[openInMaps setFrame:CGRectMake(15, 135, 114, 70)];
openInMaps = (UIButton *)[self roundCornersOnView:openInMaps onTopLeft:NO topRight:NO bottomLeft:YES bottomRight:NO radius:5.0];
}
- (UIView *)roundCornersOnView:(UIView *)view onTopLeft:(BOOL)tl topRight:(BOOL)tr bottomLeft:(BOOL)bl bottomRight:(BOOL)br radius:(float)radius {
if (tl || tr || bl || br) {
UIRectCorner corner = 0;
if (tl) {corner = corner | UIRectCornerTopLeft;}
if (tr) {corner = corner | UIRectCornerTopRight;}
if (bl) {corner = corner | UIRectCornerBottomLeft;}
if (br) {corner = corner | UIRectCornerBottomRight;}
UIView *roundedView = view;
UIBezierPath *maskPath = [UIBezierPath bezierPathWithRoundedRect:roundedView.bounds byRoundingCorners:corner cornerRadii:CGSizeMake(radius, radius)];
CAShapeLayer *maskLayer = [CAShapeLayer layer];
maskLayer.frame = roundedView.bounds;
maskLayer.path = maskPath.CGPath;
roundedView.layer.mask = maskLayer;
return roundedView;
}
return view;
}
