Question

I want to limit the character users can type in iPhone’s keyboard, so I created an array of my own. e.g. The array including 0~9 and a dot to enable users to type a price. Then I can return NO for -(BOOL)textField:shouldChangeCharactersInRange:replacementString: if the replace string is not in the array.

The problem is that the backspace button is also disabled when I use this array to filter text. Any ideas about how to enable backspace button?

Another problem is that I want to let users type their names and therefore I don’t want to let them switch to numbers and punctuaction (backspace button is also locked if I use an array to filter). How to disable the switch button on the keyboard (Now I just limit them to type a~z, blank and “.” , but I think disable the switch button might be a better way)?

Answer 1

I find a way (maybe not good enough, but it can do the work for backspace function):

- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
{
    if(textField == txtChargeAmt)
    {
        if(string.length == 0)  //backspace button is pressed
        {
            textField.text = [textField.text substringToIndex:(textField.text.length - 1)];
            return NO;
        }

        for(NSString *s in arrNumberAndDot)
        {
            if([string isEqualToString:s])
            {
                return YES;
            }
        }
        return NO;
    }
    else
        return YES;
}

Other ideas about the backspace issue are welcomed. And how to disable the switch button then?