Set a custom subclass of UINavigationBar in UINavigationController programmatically

You don't need to muck with the XIB simply use KVC.

[self.navigationController setValue:[[[CustomNavBar alloc]init] autorelease] forKeyPath:@"navigationBar"];

Since iOS5, apple provides a method to do this directly. Reference

UINavigationController *navigationController= [[UINavigationController alloc]initWithNavigationBarClass:[CustomNavBar class] toolbarClass:nil];[navigationController setViewControllers:[NSArray arrayWithObject:yourRootViewController]];

As of iOS 4, you can use the UINib class to help solve this issue.

1. Create your custom UINavigationBar subclass.
2. Create an empty xib, add a UINavigationController as the singleobject.
3. Set the class for the UINavigationController's UINavigationBar to your custom subclass.
4. Set your root view controller via one of these methods:
   • [navController setViewcontrollers[NSArray arrayWithObject:myRootVC]];
   • [navController pushViewController:myRootVC];

In code:

UINib *nib = [UINib nibWithNibName:@"YourCustomXib" bundle:nil];UINavigationController *navController =              [[nib instantiateWithOwner:nil options:nil] objectAtIndex:0];

Now you've got a UINavigationController with your custom UINavigationBar.