Which event handles object becoming/losing first responder status?

I have a UITextView, and I'd like to show UILabel 开发者_如何学JAVAonce it receives First Responder status, and hide UILabel when UITextView loses it.

What action handles becoming/losing first responder? Or perhaps there is a better way to display UILabel only when UITextView has focus?

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There is also the UITextFieldDelegate methods available to use.

(BOOL)textFieldShouldEndEditing:(UITextField *)textField;
(void)textFieldDidEndEditing:(UITextField *)textField;

These will be called before and after the UITextField loses the first responder status.

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UIView is a subclass of UIResponder. Your view will be sent a -(BOOL)becomeFirstResponder when it becomes first responder and -(BOOL)resignFirstResponder when it loses it. You can also perform some processing before both of these events from –(BOOL)canBecomeFirstResponder and –(BOOL)canResignFirstResponder. All of these methods are defined on UIResponder.

In all cases, assuming you do want to become (or resign) first responder, you should return YES to these messages.