在 UIImageView 周围设置边框

Question

我想在UIImageView上应用两种类型的边框：

1. 一个是UIImageView layer的边界。
2. 其次是UIImageView layer周围的边界。

我该怎么做？

Answer 1

试试

#define kBorderWidth 3.0
#define kCornerRadius 8.0
CALayer *borderLayer = [CALayer layer];
CGRect borderFrame = CGRectMake(0, 0, (imageView.frame.size.width), (imageView.frame.size.height));
[borderLayer setBackgroundColor:[[UIColor clearColor] CGColor]];
[borderLayer setFrame:borderFrame];
[borderLayer setCornerRadius:kCornerRadius];
[borderLayer setBorderWidth:kBorderWidth];
[borderLayer setBorderColor:[[UIColor redColor] CGColor]];
[imageView.layer addSublayer:borderLayer];

并且不要忘记导入QuartzCore/QuartzCore.h

本示例将在图层上绘制一个边界，但稍微更改其框架以使图层周围的边框。

Answer 2

另一种方式

您必须导入

#import <QuartzCore/QuartzCore.h>

然后为您的 UIImageView 添加代码

imgView.clipsToBounds = YES;
imgView.layer.cornerRadius = 8.0;
imgView.layer.borderWidth = 2.0;
imgView.layer.borderColor = [UIColor greenColor].CGColor;

Answer 3

另一种方法是添加另一个层，该层位于UIImageView的层之外，如下所示：

CALayer * externalBorder = [CALayer layer];
externalBorder.frame = CGRectMake(-1, -1, myView.frame.size.width+2, myView.frame.size.height+2);
externalBorder.borderColor = [UIColor blackColor].CGColor;
externalBorder.borderWidth = 1.0;
[myView.layer addSublayer:externalBorder];
myView.layer.masksToBounds = NO;

Answer 4

Swift 5

使用UIImageView时要小心; masksToBounds = false意味着图像将溢出

let outsideBorder = CALayer()
outsideBorder.frame = CGRect(x: -1, y: -1, width: myView.frame.size.width+2, height: myView.frame.size.height+2)
outsideBorder.borderColor = UIColor.black.cgColor
outsideBorder.borderWidth = 1.0
myView.layer.addSublayer(outsideBorder)
myView.masksToBounds = false