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;

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}];

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]
)

yourTextfield.attributedPlaceholder = NSAttributedString(string: "your placeholder text",attributes: [NSForegroundColorAttributeName: UIColor.white])

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/