像这样创建UITextField扩展:

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!])
        }
    }
}

在你的故事板或。xib中。你会看到

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/

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。

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];

在Swift中这样使用，

 let placeHolderText = textField.placeholder ?? ""
 let str = NSAttributedString(string:placeHolderText!, attributes: [NSAttributedString.Key.foregroundColor :UIColor.lightGray])
 textField.attributedPlaceholder = str

在Objective C中

NSString *placeHolder = [textField.placeholder length]>0 ? textField.placeholder: @"";
NSAttributedString *str = [[NSAttributedString alloc] initWithString:placeHolder attributes:@{ NSForegroundColorAttributeName : [UIColor lightGrayColor] }];
textField.attributedPlaceholder = str;

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