Need Help calling a function when UI Picker value selected

I am building a simple unit conversi开发者_StackOverflowon app and want to have the user select what type conversion they want and have a function called so that when they input a number in one of the text boxes the conversion gets displayed in the other. I am using an NSMutableArray.

You could use the delegate method textFieldDidEndEditing: or register for UITextFieldTextDidChangeNotification.