Question

I am developing a game, and I would like to transition between several views, e.g. Menu Screen, Game Screen, Game Over Screen etc. What would be the easiest way of doing this? I’m not sure if I should use a view stack as the order that the views are shown is not always reversed.

Answer 1

I assume by “view stack” you mean a UINavigationController?

The easiest way is to keep references to all of the view controllers somewhere, for example I see people use the application delegate a lot, so your application delegate’s class extension would look a little like:

@interface AppDelegate ()

@property (nonatomic, strong) UIViewController *rootViewController; //this is what gets set as the window's root VC
@property (nonatomic, strong) UIViewController *mainScreenViewController;
@property (nonatomic, strong) UIViewController *gameScreenViewController;
@property (nonatomic, strong) UIViewController *gameOverScreenViewController;

@end

Assume rootViewController just controls a container view for the rest of the app (You would probably actually be well served putting all this logic into the root view controller though…)

Now anytime you need to show a certain screen, call a method like:

- (void)switchToViewController:(UIViewController *)viewController
{
    [self.rootViewController.view.subviews makeObjectsPerformSelector:@selector(removeFromSuperview)];
    [self.rootViewController.view addSubview:viewController.view];
}

You can now write methods that are named more memorably like -switchToGameOverScreen

- (void)switchToGameOverScreen
{
    [self switchToViewController:self.gameOverScreenViewController];
} 

This basic pattern of view navigation is roughly found in UITabBarController and often in views controlled by UISegmentedControls.

Hopefully this helps!