我很惊讶这里有这么多糟糕的解决方案。

这里有一个永远有效的版本。

斯威夫特4.2

extension UITextField{
    @IBInspectable var placeholderColor: UIColor {
        get {
            return self.attributedPlaceholder?.attribute(.foregroundColor, at: 0, effectiveRange: nil) as? UIColor ?? .lightText
        }
        set {
            self.attributedPlaceholder = NSAttributedString(string: self.placeholder ?? "", attributes: [.foregroundColor: newValue])
        }
    }
}

提示:如果在设置颜色后更改占位符文本-颜色将重置。

这段代码在Swift3中工作:

yourTextFieldName .setValue(UIColor.init(colorLiteralRed: 80/255, green: 80/255, blue: 80/255, alpha: 1.0), forKeyPath: "_placeholderLabel.textColor")

如果你有任何问题，请告诉我。

它更多的是个性化你的textField，但无论如何，我将分享这段代码从另一个页面，使它更好一点:

import UIKit
extension UITextField {
func setBottomLine(borderColor: UIColor, fontColor: UIColor, placeHolderColor:UIColor, placeHolder: String) {
    self.borderStyle = UITextBorderStyle.none
    self.backgroundColor = UIColor.clear
    let borderLine = UIView()
    let height = 1.0
    borderLine.frame = CGRect(x: 0, y: Double(self.frame.height) - height, width: Double(self.frame.width), height: height)
    self.textColor = fontColor
    borderLine.backgroundColor = borderColor
    self.addSubview(borderLine)
    self.attributedPlaceholder = NSAttributedString(
        string: placeHolder,
        attributes: [NSAttributedStringKey.foregroundColor: placeHolderColor]
    )
  }
}

你可以这样使用它:

self.textField.setBottomLine(borderColor: lineColor, fontColor: fontColor, placeHolderColor: placeHolderColor, placeHolder: placeHolder)

知道你有一个UITextField连接到一个ViewController。

来源:http://codepany.com/blog/swift-3-custom-uitextfield-with-single-line-input/

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])
            }
        }
    }
}

    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!])
                }
            } 
}

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