UIScrollerView Top screen backColor

UIScrollView+topBackColor.mm

-(void)setTopBackgroundColor:(UIColor *)color{
    
    CGRect frame = self.bounds;
    frame.origin.y = -CGRectGetHeight(UIScreen.mainScreen.bounds);
    frame.size = UIScreen.mainScreen.bounds.size;
    UIView* grayView = [UIView.alloc initWithFrame:frame];
    grayView.backgroundColor = color;
    [self addSubview:grayView];
}