//设置textfile的Placeholder的颜色和字体大小
nameText.attributedPlaceholder = NSAttributedString.init(string: "用户名", attributes: [NSForegroundColorAttributeName: UIColor.white,NSFontAttributeName: UIFont.systemFont(ofSize: 18)])
//设置textfile的Placeholder的颜色和字体大小
nameText.attributedPlaceholder = NSAttributedString.init(string: "用户名", attributes: [NSForegroundColorAttributeName: UIColor.white,NSFontAttributeName: UIFont.systemFont(ofSize: 18)])