IOS开发之如何在UILabel和UIButton添加下划线

NSMutableAttributedString *str = [[NSMutableAttributedString alloc] initWithString:@"查看所有中奖记录"]; 
NSRange strRange = {0,[str length]}; 
[str addAttribute:NSUnderlineStyleAttributeName value:[NSNumber numberWithInteger:NSUnderlineStyleSingle] range:strRange]; 
[_awardDisplayBtn setAttributedTitle:str forState:UIControlStateNormal]; 

#import  
 
@interface HyperlinksButton : UIButton 
{ 
  UIColor *lineColor; 
} 
-(void)setColor:(UIColor*)color; 
@end 

HyperlinksButton.m 
[objc] view plain copy print?
#import "HyperlinksButton.h" 
 
@implementation HyperlinksButton 
 
- (id)initWithFrame:(CGRect)frame 
{ 
  self = [super initWithFrame:frame]; 
  if (self) { 
     
  } 
  return self; 
} 
 
-(void)setColor:(UIColor *)color{ 
  lineColor = [color copy]; 
  [self setNeedsDisplay]; 
} 
 
 
- (void) drawRect:(CGRect)rect { 
  CGRect textRect = self.titleLabel.frame; 
  CGContextRef contextRef = UIGraphicsGetCurrentContext(); 
   
  CGFloat descender = self.titleLabel.font.descender; 
  if([lineColor isKindOfClass:[UIColor class]]){ 
    CGContextSetStrokeColorWithColor(contextRef, lineColor.CGColor); 
  } 
   
  CGContextMoveToPoint(contextRef, textRect.origin.x, textRect.origin.y + textRect.size.height + descender+1); 
  CGContextAddLineToPoint(contextRef, textRect.origin.x + textRect.size.width, textRect.origin.y + textRect.size.height + descender+1); 
   
  CGContextClosePath(contextRef); 
  CGContextDrawPath(contextRef, kCGPathStroke); 
} 
@end