我有一个UIButton,当我点击它,下降给一个效果click/tap.

我的问题是,我必须添加一个black border围绕UIButton,但增加这保持边界的静态,它不向下移动与UIButton,这让我有点击效果的代码UIButton是这样的:
- (void)drawRect:(CGRect)rect
{
[super drawRect:rect];
CGSize size = self.bounds.size;
CGContextRef context = UIGraphicsGetCurrentContext();
CGRect faceRect = CGRectMake(0, 0, size.width, size.height);
UIGraphicsBeginImageContextWithOptions(faceRect.size, NO, 0.0);
[[self faceColorForState:self.state] set];
[self drawRoundedRect:faceRect radius:self.radius context:UIGraphicsGetCurrentContext()];
UIImage *faceImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
[[self sideColorForState:self.state] set];
CGRect sideRect = CGRectMake(0, size.height * 1.0 / 4.0, size.width, size.height * 3.0 / 4.0);
[self drawRoundedRect:sideRect radius:self.radius context:context];
CGRect faceShrinkedRect;
if(self.state == UIControlStateSelected || self.state == …Run Code Online (Sandbox Code Playgroud)