use in textfield number input only

numberOnly.m

// textField.keyboardType = UIKeyboardTypeNumbersAndPunctuation;



- (BOOL)doesStringContainDecimal:(NSString*) string
{
    NSString *searchForDecimal = @".";
    NSRange range = [string rangeOfString:searchForDecimal];
    
    //If we find a decimal return YES. Otherwise, NO
    if (range.location != NSNotFound)
        return YES;
    return NO;
}

- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
{
    NSCharacterSet *nonNumberSet = [[NSCharacterSet characterSetWithCharactersInString:@"0123456789."] invertedSet];
    
    // allow backspace
    if (range.length > 0 && [string length] == 0) {
        return YES;
    }
    
    
    // do not allow . at the beggining
    if (range.location == 0 && [string isEqualToString:@"."]) {
        
        return NO;
    }
    
    // do not allow . if exist a .
    if ([string isEqualToString:@"."] && [self doesStringContainDecimal:textField.text] == YES) {
        
        return NO;
        
    }
    
    
    // set the text field value manually
    NSString *newValue = [[textField text] stringByReplacingCharactersInRange:range withString:string];
    newValue = [[newValue componentsSeparatedByCharactersInSet:nonNumberSet] componentsJoinedByString:@""];
    textField.text = newValue;
    // return NO because we're manually setting the value
    return NO;
}