Question

I have implemented a TTPickerTextField in my application,
I would like to limit the number of choice the user can do it.

Now, the TTPickerTextField has no limit. The user can select an unlimited number of fields.

Thank a lot.
Sahid

Answer 1

TTPickerTextField is a subclass of UITextField, so you should be able to use its delegate methods to do what you want. You can do this by implementing the textField:shouldChangeCharactersInRange delegate method and returning NO when the maximum number of tokens are reached.

Where you create and initialize the TTPickerTextField, set the delegate method appropriately:

pickerTextField.delegate = self;

Then your delegate object (probably the controller) can implement the delegate method to limit the number of tokens:

- (BOOL) textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
{
    BOOL canEdit = YES;

    if (textField == pickerTextField)  // 'pickerTextField' is the Three20's picker textfield that you want to limit.
    {
        if (range.length == 0 && pickerTextField.cells.count >= MAX_NUMBER_OF_TOKENS)
        {
            canEdit = NO;
        }
    }

    return canEdit;
}