限定小数点位数

- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string {

NSRange last = [_borMoneyTextField.text rangeOfString:@"."];

        long digit = range.location - last.location;

        if (digit > 1) {//保留一位小数

            return NO;

        }

}