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])

您可以使用带属性的字符串设置占位符文本。只需要把你想要的颜色传递给属性参数。

斯威夫特5:

let myTextField = UITextField(frame: CGRect(x: 0, y: 0, width: 200, height: 30))
myTextField.backgroundColor = .blue
myTextField.attributedPlaceholder = NSAttributedString(
    string: "Placeholder Text",
    attributes: [NSAttributedString.Key.foregroundColor: UIColor.white]
)

斯威夫特3:

myTextField.attributedPlaceholder = NSAttributedString(
    string: "Placeholder Text",
    attributes: [NSAttributedStringKey.foregroundColor: UIColor.white]
)

年长的迅速:

myTextField.attributedPlaceholder = NSAttributedString(
    string: "Placeholder Text",
    attributes: [NSForegroundColorAttributeName: UIColor.white]
)

您可以使用Interface Builder快速完成此任务，而无需添加一行代码。

选择UITextField并打开右边的标识检查器:

点击加号按钮，添加一个新的运行时属性:

placeholderLabel。textColor (Swift 4)

_placeholderLabel。textColor (Swift 3或更少)

使用颜色作为类型并选择颜色。

就是这样。

你不会看到结果，直到你再次运行你的应用程序。

为迅速

func setPlaceholderColor(textField: UITextField, placeholderText: String) {
    textField.attributedPlaceholder = NSAttributedString(string: placeholderText, attributes: [NSForegroundColorAttributeName: UIColor.pelorBlack])
}

你可以用这个;

self.setPlaceholderColor(textField: self.emailTextField, placeholderText: "E-Mail/Username")

对于Swift 4.0, X-code 9.1版本或iOS 11，您可以使用以下语法来拥有不同的占位符颜色

textField.attributedPlaceholder = NSAttributedString(string: "Placeholder Text", attributes: [NSAttributedStringKey.foregroundColor : UIColor.white])

Swift 3(可能是2)，你可以覆盖didSet占位符在UITextField子类上应用属性，这样:

override var placeholder: String? {

    didSet {
        guard let tmpText = placeholder else {
            self.attributedPlaceholder = NSAttributedString(string: "")
            return
        }

        let textRange = NSMakeRange(0, tmpText.characters.count)
        let attributedText = NSMutableAttributedString(string: tmpText)
        attributedText.addAttribute(NSForegroundColorAttributeName , value:UIColor(white:147.0/255.0, alpha:1.0), range: textRange)

        self.attributedPlaceholder = attributedText
    }
}