A button is added to the navigation bar which is shown on all the screens. I need to hide it from all screens except one

In my app for iPad, I have first a welcome 开发者_高级运维screen then home screen and then home screen navigates to rest of the screens. I have made a button on navigation bar of the home screen which takes the user back to the welcome screen. But that button is shown on all other screens as well. I want to remove that button from all the screens and show it only in the home screen. How can I hide that button from all other screens and make it visible only on the home screen?

Thanks PC

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In viewDidDisappear:

self.navigationItem.rightBarButtonItem = nil; 
// or on whichever side your button is

In viewWillAppear:

self.navigationItem.rightBarButtonItem = self.showWelcomeButton; 
// self.showWelcomeButton is a retained UIBarButtonItem property