view加底线

1. CALayer *bottomBorder = [CALayer layer];  
2. float height1=view.frame.size.height-0.5f;  
3. float width1=view.frame.size.width;  
4. bottomBorder.frame = CGRectMake(0.0f, height1, width1, 0.5f);  
5. bottomBorder.backgroundColor = [UIColor blackColor].CGColor;  
6. [view.layer addSublayer:bottomBorder];