//CALayer - 渲染层
CALayer *layer = [CALayer layer];
layer.frame = CGRectMake(0, 63.5, [UIScreen mainScreen].bounds.size.width, 0.5);
//UIColor要转CGColor
layer.backgroundColor = [UIColor colorWithRed:0.70 green:0.70 blue:0.70 alpha:1.00].CGColor;
[self.layer addSublayer:layer];