Detect backspace in UITextField on a blank textfield [duplicate]

Answer 1

:) just for the title "Detect backspace", where I use UIKeyboardTypeNumberPad.

I also meet the same question tonight, and following is my code to find it out:

- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
{
    NSLog([NSString stringWithFormat:@"%d", [string length]]);
}

Because with UIKeyboardTypeNumberPad, user can only input Number or backspace, so when the length of string is 0, it must be backspace key.

Hope the above will do some help.