ios trigger an event (function) when and how to prepare the input box when the input focus textField

ios trigger an event (function) when and how to prepare the input box when the input focus textField
Reply:
Write a judge, when appropriate won the first, and went to call a method
Reply:
isFirstResponder to determine the focus, and then call the method
Reply:
Not sure what you mean
If you want to capture this event when uitextfield is clicked to get the focus, you can achieve UITextfieldDelegate related methods, and these methods are UITextfield event handler.
If you want to get through the code to allow uitextfield focus, adjust [uitextfield becomeFirstResponder]
Reply:
TextField look into the delegate, then there

 - (BOOL) textFieldShouldBeginEditing: (UITextField *) textField; / / return NO to disallow editing 
.- (Void) textFieldDidBeginEditing: (UITextField *) textField;