iOS 7 UIBarButton back button arrow color

Question

To change the back button chevron color for a specific navigation controller*:

self.navigationController.navigationBar.tintColor = [UIColor whiteColor];

*If you are using an app with more than 1 navigation controller, and you want this chevron color to apply to each, you may want to use the appearance proxy to set the back button chevron for every navigation controller, as follows:

[[UINavigationBar appearance] setTintColor:[UIColor whiteColor]];

And for good measure, in swift (thanks to Jay Mayu in the comments):

UINavigationBar.appearance().tintColor = UIColor.whiteColor()

You have to set the tintColor of the entire app.

self.window.tintColor = [UIColor redColor];

Or in Swift 3:

self.window?.tintColor = UIColor.blue

Source: iOS 7 UI Transition Guide

You can set the color on the entire app navigation's bar using the method

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:
(NSDictionary *)launchOptions{
    [[UINavigationBar appearance] setTintColor:[UIColor whiteColor]];
}

It is possible to change only arrow's color (not back button title's color) on this way:

[[self.navigationController.navigationBar.subviews lastObject] setTintColor:[UIColor blackColor]];

Navigation bar contains subview of _UINavigationBarBackIndicatorView type (last item in subviews array) which represents arrow.

Result is navigation bar with different colors of back button arrow and back button title

If you are using storyboards you could set the navigation bar tint colour.

Inside the rootViewController that initializes the navigationController, I put this code inside my viewDidAppear method:

//set back button color
[[UIBarButtonItem appearanceWhenContainedIn:[UINavigationBar class], nil] setTitleTextAttributes:[NSDictionary dictionaryWithObjectsAndKeys:[UIColor whiteColor], UITextAttributeTextColor,nil] forState:UIControlStateNormal];
//set back button arrow color
[self.navigationController.navigationBar setTintColor:[UIColor whiteColor]];