ios Changing UIScrollView scrollbar color to different colors

Here's more safe Swift 3 method:

func scrollViewDidScroll(_ scrollView: UIScrollView) {
    let verticalIndicator = scrollView.subviews.last as? UIImageView
    verticalIndicator?.backgroundColor = UIColor.green
}

Unfortunately you can't, of course you can always roll your own. These are your options:

UIScrollViewIndicatorStyleDefault:

The default style of scroll indicator, which is black with a white border. This style is good against any content background.

UIScrollViewIndicatorStyleBlack:

A style of indicator which is black and smaller than the default style. This style is good against a white content background.

UIScrollViewIndicatorStyleWhite:

A style of indicator is white and smaller than the default style. This style is good against a black content background.