Obtain notifies of connecting and disconnecting screens

ScreenNotify.mm

//setting notifiers
- (void)setupScreenConnectionNotificationHandlers {
    NSNotificationCenter* center = [NSNotificationCenter 
                                      defaultCenter];
 
    [center addObserver:self selector:@selector(
                                handleScreenConnect:)
            name:UIScreenDidConnectNotification object:nil];
    [center addObserver:self selector:@selector(
                                handleScreenDisconnect:)
            name:UIScreenDidDisconnectNotification object:nil];
}

//handling screen connection
- (void)handleScreenConnect:(NSNotification*)aNotification
{
    UIScreen*    newScreen = [aNotification object];
    CGRect        screenBounds = newScreen.bounds;
 
    if (!_secondWindow)
    {
        _secondWindow = [[UIWindow alloc] initWithFrame:screenBounds];
        _secondWindow.screen = newScreen;
 
        // Set the initial UI for the window.
        [viewController displaySelectionInSecondaryWindow:
                                                _secondWindow];
    }
}

//handling screen disconnection
- (void)handleScreenDisconnect:(NSNotification*)aNotification
{
    if (_secondWindow)
    {
        // Hide and then delete the window.
        _secondWindow.hidden = YES;
        [_secondWindow release];
        _secondWindow = nil;
 
        // Update the main screen based on what is showing here.
        [viewController displaySelectionOnMainScreen];
    }
 
}