添加阴影效果

@implementation ICSDropShadowView

- (void)drawRect:(CGRect)rect
{
    self.layer.shadowOffset = CGSizeZero;
    self.layer.shadowOpacity = 0.7f;
    
    UIBezierPath *shadowPath = [UIBezierPath bezierPathWithRect:self.bounds];
    self.layer.shadowPath = shadowPath.CGPath;
}

设置阴影效果