extension UITextField{
            @IBInspectable var placeHolderColor: UIColor? {
                get {
                    return self.placeHolderColor
                }
                set {
                    self.attributedPlaceholder = NSAttributedString(string:self.placeholder != nil ?
        self.placeholder! : "",
        attributes:[NSAttributedString.Key.foregroundColor : newValue!])
                }
            } 
}

对于目标C:

UIColor *color = [UIColor colorWithRed:0.44 green:0.44 blue:0.44 alpha:1.0];
 emailTextField.attributedPlaceholder = [[NSAttributedString alloc] initWithString:@"Friend's Email" attributes:@{NSForegroundColorAttributeName: color}];

迅速:

emailTextField.attributedPlaceholder = NSAttributedString(string: "Friend's Email",
                             attributes: [NSAttributedString.Key.foregroundColor: UIColor.white])

在我的例子中，我必须将占位符设置为黑色。UITextField的名字是passwordText。下面的代码是在Swift 5中测试的，对我来说工作得很好。我也有一个现有的文本对应的占位符。

let placeholderColor = UIColor.black
passwordText.attributedPlaceholder = NSAttributedString(string: passwordText.placeholder!, attributes: [NSAttributedString.Key.foregroundColor : placeholderColor])

Swift 4:

txtControl.attributedPlaceholder = NSAttributedString(string: "Placeholder String...",attributes: [NSAttributedStringKey.foregroundColor: UIColor.gray])

objective - c:

UIColor *color = [UIColor grayColor];
txtControl.attributedPlaceholder = [[NSAttributedString alloc] initWithString:@"Placeholder String..." attributes:@{NSForegroundColorAttributeName: color}];

就我而言，我做了以下事情:

extension UITextField {
    @IBInspectable var placeHolderColor: UIColor? {
        get {
            if let color = self.attributedPlaceholder?.attribute(.foregroundColor, at: 0, effectiveRange: nil) as? UIColor {
                return color
            }
            return nil
        }
        set (setOptionalColor) {
            if let setColor = setOptionalColor {
                let string = self.placeholder ?? ""
                self.attributedPlaceholder = NSAttributedString(string: string , attributes:[NSAttributedString.Key.foregroundColor: setColor])
            }
        }
    }
}

在Swift 3.0中，使用

let color = UIColor.lightText
textField.attributedPlaceholder = NSAttributedString(string: textField.placeholder, attributes: [NSForegroundColorAttributeName : color])

在Siwft 5.0 +使用

let color = UIColor.lightText
let placeholder = textField.placeholder ?? "" //There should be a placeholder set in storyboard or elsewhere string or pass empty
textField.attributedPlaceholder = NSAttributedString(string: placeholder, attributes: [NSAttributedString.Key.foregroundColor : color])