iphone - UISegmentedControl register taps on selected segment

Question

I have a segmented control where the user can select how to order a list. Works fine.

However, I would like that when an already selected segment is tapped, the order gets inverted. I have all the code in place, but I don't know how to register the taps on those segments. It seems the only control event you can use is UIControlEventValueChanged, but that isn't working (since the selected segment isn't actually changing).

Is there a solution for this? And if so, what is it?

Thanks in advance!

Answer 1

You can subclass UISegmentedControl, and then override setSelectedSegmentIndex:

- (void) setSelectedSegmentIndex:(NSInteger)toValue {
    if (self.selectedSegmentIndex == toValue) {
        [super setSelectedSegmentIndex:UISegmentedControlNoSegment];
    } else {
        [super setSelectedSegmentIndex:toValue];        
    }
}

If using IB, make sure you set the class of your UISegmentedControl to your subclass.

Now you can listen for the same UIControlEventValueChanged as you would normally, except if the user deselected the segment, you will see a selectedSegmentIndex equal to UISegmentedControlNoSegment:

-(IBAction) valueChanged: (id) sender {
    UISegmentedControl *segmentedControl = (UISegmentedControl*) sender;
    switch ([segmentedControl selectedSegmentIndex]) {
        case 0:
            // do something
            break;
        case 1:
            // do something
            break;
        case UISegmentedControlNoSegment:
            // do something
            break;
        default:
            NSLog(@"No option for: %d", [segmentedControl selectedSegmentIndex]);
    }
}