How to detect UIKeyboard “backspace” button touch on UITextField? [duplicate]

Answer 1

First of all your UIViewController that references the UITextField needs to conform to the UITextFieldDelegate protocol. Then set your class as delegate to the UITextField (eg. [myTextField setDelegate:self] ). Then in your class you add the following. When a string of "" is sent as the replacementString you know it's backspace.

(BOOL)textField:(UITextField *)textField 
      shouldChangeCharactersInRange:(NSRange)range 
      replacementString:(NSString *)string
{                
    if ([string isEqualToString:@""]) {
        NSLog(@"Backspace");            
    }
    return YES;
}