Xcode How to keep track of certain screens opened?

Working with a QR scanner for IOS. Generated my own unique QR codes to match each "screen". Below is the code snippet used to list all the screens the QR Scanner finds.That woks fine and does scan the QR Code and opens the corresponding screen.

What I need now is to keep track of a certain screen and how many times it's scanned and displayed so that if it is displayed more than say 3 times a different screen will appear.

The idea is that if the same QR Code is scanned more than 3 times a warning screen will appear. Any ideas how to do this? Thanks:)

//loop through every screen in the applications list of screens
    for(int i = 0; i < [[appDelegate.rootApp screens] count]; i++){
        BT_item *thisScreen = [[appDelegate.rootApp screens] objectAtIndex:i];
      //  [BT_debugger showIt:self message:[NSString stringWithFormat:@"thisScreen:%@", thisScreen.itemId]];

        if ([thisScreen.itemId isEqualToString:result] ) {
            [self handleTapToLoadScreen:thisScreen theMenuItemData:nil];
            return;`enter code here`