Xcode 9.2 Swift 4

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

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])
            }
        }
    }
}

用于更改占位符文本颜色的Objective C代码。

首先导入这个objc/runtime类-

#进口< objc / >

然后替换文本字段名称- Ivar Ivar = class_getinstancvariable ([UITextField类]，"_placeholderLabel"); UILabel *placeholderLabel = object_getIvar(YourTxtField, ivar); placeholderLabel。textColor = [UIColor whiteColor];

只要把下面的代码写进Appdelegate的didFinishLaunchingWithOptions方法，如果你想在Swift 4.2编写的整个应用程序中进行更改，使用这个方法

UILabel.appearance(whenContainedInInstancesOf: [UITextField.self]).textColor = UIColor.white

    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!])
                }
            } 
}

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])