[txt_field setValue:ColorFromHEX(@"#525252") forKeyPath:@"_placeholderLabel.textColor"];

[txt_field setValue:ColorFromHEX(@"#525252") forKeyPath:@"_placeholderLabel.textColor"];

自从ios6在UIViews中引入了带属性字符串，就可以像这样为占位符文本分配颜色:

if ([textField respondsToSelector:@selector(setAttributedPlaceholder:)]) {
  UIColor *color = [UIColor blackColor];
  textField.attributedPlaceholder = [[NSAttributedString alloc] initWithString:placeholderText attributes:@{NSForegroundColorAttributeName: color}];
} else {
  NSLog(@"Cannot set placeholder text's color, because deployment target is earlier than iOS 6.0");
  // TODO: Add fall-back code to set placeholder color.
}

iOS 6及后续版本在UITextField上提供attributedPlaceholder。 iOS 3.2及更高版本提供了setAttributes:range: on NSMutableAttributedString。

您可以执行以下操作:

NSMutableAttributedString *ms = [[NSMutableAttributedString alloc] initWithString:self.yourInput.placeholder];
UIFont *placeholderFont = self.yourInput.font;
NSRange fullRange = NSMakeRange(0, ms.length);
NSDictionary *newProps = @{NSForegroundColorAttributeName:[UIColor yourColor], NSFontAttributeName:placeholderFont};
[ms setAttributes:newProps range:fullRange];
self.yourInput.attributedPlaceholder = ms;

简单无痛，对一些人来说可能是一个简单的选择。

_placeholderLabel.textColor

不建议制作，Apple可能会拒绝您的提交。

在swift 3中。X

textField.attributedPlaceholder = NSAttributedString(string: "placeholder text", attributes:[NSForegroundColorAttributeName: UIColor.black])

在swift 5中

textField.attributedPlaceholder = NSAttributedString(string: "placeholder text", attributes: [NSAttributedString.Key.foregroundColor : UIColor.black])