有没有一种方法，以一个UIView的边界的两侧设置为一种颜色，离开顶部和底部的另一？
Answer 1:
都能跟得上，CALayer的边界不支持这种行为。 最简单的方式来完成你想要的是添加具有您所需的边框颜色作为您的视图的每一侧其背景色的N点范围内的不透明子视图。
例：
CGSize mainViewSize = theView.bounds.size;
CGFloat borderWidth = 2;
UIColor *borderColor = [UIColor redColor];
UIView *leftView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, borderWidth, mainViewSize.height)];
UIView *rightView = [[UIView alloc] initWithFrame:CGRectMake(mainViewSize.width - borderWidth, 0, borderWidth, mainViewSize.height)];
leftView.opaque = YES;
rightView.opaque = YES;
leftView.backgroundColor = borderColor;
rightView.backgroundColor = borderColor;
// for bonus points, set the views' autoresizing mask so they'll stay with the edges:
leftView.autoresizingMask = UIViewAutoresizingFlexibleHeight | UIViewAutoresizingFlexibleRightMargin;
rightView.autoresizingMask = UIViewAutoresizingFlexibleHeight | UIViewAutoresizingFlexibleLeftMargin;
[theView addSubview:leftView];
[theView addSubview:rightView];
[leftView release];
[rightView release];
请注意，这将不完全匹配的CALayer的行为边界，左，右边界的意见永远是他们的上海华盈的边界之内。
Answer 2:
与就像边界的观点，答案是很不错的，但请记住，每一个观点是，花费大量内存的UI对象。
我用对子级uivew的层油漆颜色的笔画上已经存在的UIView。
-(CAShapeLayer*)drawLineFromPoint:(CGPoint)fromPoint toPoint:(CGPoint) toPoint withColor:(UIColor *)color andLineWidth:(CGFloat)lineWidth{
CAShapeLayer *lineShape = nil;
CGMutablePathRef linePath = nil;
linePath = CGPathCreateMutable();
lineShape = [CAShapeLayer layer];
lineShape.lineWidth = lineWidth;
lineShape.strokeColor = color.CGColor;
NSUInteger x = fromPoint.x;
NSUInteger y = fromPoint.y;
NSUInteger toX = toPoint.x;
NSUInteger toY = toPoint.y;
CGPathMoveToPoint(linePath, nil, x, y);
CGPathAddLineToPoint(linePath, nil, toX, toY);
lineShape.path = linePath;
CGPathRelease(linePath);
return lineShape;}
并把它添加到我们的视线。
CAShapeLayer* borderLine=[self drawLineFromPoint:CGPointMake(0, 0) toPoint:CGPointMake(0,_myView.frame.size.height) withColor:[UIColor lightGrayColor] andLineWidth:1.0f];
[_myView.layer addSublayer:borderLine];
所以......我们需要一个点，实际上画由上到我们认为的底部线。 其结果是，有一条线，看起来像一个像素宽度的边框。
Answer 3:
更新了雨燕3.0
我写了一个斯威夫特扩展名（一个UIButton），模拟在一个UIView的任何一侧设置一个边界给定的颜色和宽度。 它类似于@Noah威瑟斯庞的做法，而是自成一体，自动布局基于约束的。
// Swift 3.0
extension UIView {
enum Border {
case left
case right
case top
case bottom
}
func setBorder(border: UIView.Border, weight: CGFloat, color: UIColor ) {
let lineView = UIView()
addSubview(lineView)
lineView.backgroundColor = color
lineView.translatesAutoresizingMaskIntoConstraints = false
switch border {
case .left:
lineView.leftAnchor.constraint(equalTo: leftAnchor).isActive = true
lineView.topAnchor.constraint(equalTo: topAnchor).isActive = true
lineView.bottomAnchor.constraint(equalTo: bottomAnchor).isActive = true
lineView.widthAnchor.constraint(equalToConstant: weight).isActive = true
case .right:
lineView.rightAnchor.constraint(equalTo: rightAnchor).isActive = true
lineView.topAnchor.constraint(equalTo: topAnchor).isActive = true
lineView.bottomAnchor.constraint(equalTo: bottomAnchor).isActive = true
lineView.widthAnchor.constraint(equalToConstant: weight).isActive = true
case .top:
lineView.topAnchor.constraint(equalTo: topAnchor).isActive = true
lineView.leftAnchor.constraint(equalTo: leftAnchor).isActive = true
lineView.rightAnchor.constraint(equalTo: rightAnchor).isActive = true
lineView.heightAnchor.constraint(equalToConstant: weight).isActive = true
case .bottom:
lineView.bottomAnchor.constraint(equalTo: bottomAnchor).isActive = true
lineView.leftAnchor.constraint(equalTo: leftAnchor).isActive = true
lineView.rightAnchor.constraint(equalTo: rightAnchor).isActive = true
lineView.heightAnchor.constraint(equalToConstant: weight).isActive = true
}
}
}
Answer 4:
这听起来像是两个答案之一：
如果您的视图是一个静态的大小，那么只要把它背后一个UIView是2个像素宽，比你的前视图较短的2个像素。
如果它是非静态的大小，那么你可以做同样的，调整大小，只要您的前景视图被调整为后盾视图，或实现实现一个UIView的自定义对象，并实现（覆盖）你自己的drawRect例程。
Answer 5:
NAUIViewWithBorders奏效了我。 又见创作者的SO张贴在这里 。 值得一试，如果你需要这个功能，超过一对夫妇的意见。
Answer 6:
public extension UIView {
// Border type and arbitrary tag values to identify UIView borders as subviews
public enum BorderType: Int {
case left = 20000
case right = 20001
case top = 20002
case bottom = 20003
}
public func addBorder(borderType: BorderType, width: CGFloat, color: UIColor) {
// figure out frame and resizing based on border type
var autoresizingMask: UIViewAutoresizing
var layerFrame: CGRect
switch borderType {
case .left:
layerFrame = CGRect(x: 0, y: 0, width: width, height: self.bounds.height)
autoresizingMask = [ .flexibleHeight, .flexibleRightMargin ]
case .right:
layerFrame = CGRect(x: self.bounds.width - width, y: 0, width: width, height: self.bounds.height)
autoresizingMask = [ .flexibleHeight, .flexibleLeftMargin ]
case .top:
layerFrame = CGRect(x: 0, y: 0, width: self.bounds.width, height: width)
autoresizingMask = [ .flexibleWidth, .flexibleBottomMargin ]
case .bottom:
layerFrame = CGRect(x: 0, y: self.bounds.height - width, width: self.bounds.width, height: width)
autoresizingMask = [ .flexibleWidth, .flexibleTopMargin ]
}
// look for the existing border in subviews
var newView: UIView?
for eachSubview in self.subviews {
if eachSubview.tag == borderType.rawValue {
newView = eachSubview
break
}
}
// set properties on existing view, or create a new one
if newView == nil {
newView = UIView(frame: layerFrame)
newView?.tag = borderType.rawValue
self.addSubview(newView!)
} else {
newView?.frame = layerFrame
}
newView?.backgroundColor = color
newView?.autoresizingMask = autoresizingMask
}
文章来源: UIView set only side borders
