iPhone Keyboard key value return

I would like to know if a method like touchesBegan for touches Event exists for the iPhone keyboard. I mean 开发者_运维百科just how to know when I press a key, which value is it. (Don't display it on UITextfield or UILabel but display it with an NSLog for example). Is there any way?

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You want the UITextFieldDelegate Protocol method:

– textField:shouldChangeCharactersInRange:replacementString:

The keyboard sends this every time a key is pressed so you can decide if you want to display the character associated with the key or perform some other action.

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Accessing the keyboard view direct is strictly undocumented, so don't think of applying it to any AppStore apps.

However, you can make an off-screen text field, and use it to capture keyboard input.