self.tabBarItem respondsToSelector always returns no

I am trying to change the font color on tab bar items. I'm using code from this post:

change tabbar text color,iPhone

My code is as follows:

if ([self.tabBarItem respondsToSelector:@selector(setTitleTextAttributes:)]) {
    NSLog(@"yes");
    [self.tabBarItem setTitleTextAttributes:[NSDictionary dictionaryWithObjectsAndKeys:
                                             darkGreen, UITextAttributeTextColor,
                                             nil] forState:UIControlStateNormal];
}
else {
    NSLog(@"no");
}

respondsToSelector always returns no, and I'm stuck as to how to fix it. This code block is in viewDidLoad, and the class is a subclass of UITabBarController.

Any ideas?

This method setTitleTextAttributes: doesn't exists at all, the correct signature of that method is setTitleTextAttributes: forState:

if ([self.tabBarItem respondsToSelector:@selector(setTitleTextAttributes: forState:)]) {
    NSLog(@"yes");
    [self.tabBarItem setTitleTextAttributes:[NSDictionary dictionaryWithObjectsAndKeys:
                                             darkGreen, UITextAttributeTextColor,
                                             nil] forState:UIControlStateNormal];
}
else {
    NSLog(@"no");
}