您必须从UITextView的属性更改白色颜色

1 .添加UIScrollViewDelegate

@interface ViewController : UIViewController<UIScrollViewDelegate>
@end

2.在实现部分增加scrollViewDidScroll

如果你要换新的颜色

func scrollViewDidScroll(scrollView: UIScrollView){
        let verticalIndicator: UIImageView = (scrollView.subviews[(scrollView.subviews.count - 1)] as! UIImageView)
        verticalIndicator.backgroundColor = UIColor.greenColor()

        let horizontalIndicator: UIImageView = (scrollView.subviews[(scrollView.subviews.count - 2)] as! UIImageView)
        horizontalIndicator.backgroundColor = UIColor.blueColor()
   }

使用以下代码更新UIScrollView的指示器颜色

func scrollViewDidScroll(_ scrollView: UIScrollView) {
    let verticalIndicator: UIImageView = (scrollView.subviews[(scrollView.subviews.count - 1)] as! UIImageView)

    verticalIndicator.backgroundColor = UIColor(red: 211/255.0, green: 138/255.0, blue: 252/255.0, alpha: 1).

}