UINavigationController bar button Trigger

How can I trigger when a bar button is clicked in UINavigationController?

As I need to reset the image in the details view开发者_运维问答 when the bar button item "Back" is clicked.

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Question is a bit vague. 2 possible answers.

1. Link the bar button item in IB to a method in your view controller object that does the reset when clicked.

2. I assume you want to reset something when the view controller unloads or disappears. You will want to see -()viewdidunload. http://developer.apple.com/library/ios/ipad/#documentation/uikit/reference/UIViewController_Class/Reference/Reference.html