UISegmentedControl register taps on selected segment

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]);
    }
}