在 xib 中可以通過user defined runtime attributes來設置邊框的相關屬性，如圖
user defined runtime attributes.png
so，我們可以利用
分類 和 iOS 的IBInspectable關鍵字在 xib 添加自定義的屬性。原理如下：
給 UIView 擴展一個分類，用IBInspectable修飾符來定義cornerRadius、borderWidth和borderColor屬性，即可在 xib 上看見新增的三個屬性了。
WX20181213-122949@2x.png
代碼如下，源文件請點擊：https://github.com/isWinner/LayerXibDemo
Object-C
@interface UIView (BorderCircle)
/* 圓角半徑 */
@property(nonatomic, assign) IBInspectable CGFloat cornerRadius;
/* 邊框寬度 */
@property(nonatomic, assign) IBInspectable CGFloat borderWidth;
/* 邊框顏色 */
@property(nonatomic, weak) IBInspectable UIColor *borderColor;
@end
@implementation UIView (BorderCircle)
#pragma mark - -- borderColor
-(void)setBorderColor:(UIColor *)borderColor
{
self.layer.borderColor = borderColor.CGColor;
}
-(UIColor *)borderColor
{
return [UIColor colorWithCGColor:self.layer.borderColor];
}
#pragma mark - -- borderWidth
-(void)setBorderWidth:(CGFloat)borderWidth
{
self.layer.borderWidth = borderWidth;
}
-(CGFloat)borderWidth
{
return self.layer.borderWidth;
}
#pragma mark - -- cornerRadius
-(void)setCornerRadius:(CGFloat)cornerRadius
{
self.layer.masksToBounds = (cornerRadius>0);
self.layer.cornerRadius = cornerRadius;
}
-(CGFloat)cornerRadius
{
return self.layer.cornerRadius;
}
@end
Swift
extension UIView {
// 圓角
@IBInspectable var cornerRadius: CGFloat {
get {
return layer.cornerRadius
} set {
layer.masksToBounds = (newValue > 0)
layer.cornerRadius = newValue
}
}
// 邊線寬度
@IBInspectable var borderWidth: CGFloat {
get {
return layer.borderWidth
} set {
layer.borderWidth = newValue
}
}
// 邊線顏色
@IBInspectable var borderColor: UIColor {
get {
return UIColor(cgColor: layer.borderColor!)
} set {
layer.borderColor = newValue.cgColor
}
}
}
