故事板场景“游戏结束”屏幕

Question

I'm new to programming and Obj-c and looking for some clarity on a problem I'm having. I'm using storyboards to present each page of my game and in the main game scene, I have code to instantiate the Game Over screen at a certain time but I'm concerned that the way I'm calling the new scene is not the right way to get what I'm after.

Currently the main scene continues running underneath the Game Over screen, instead I'd like it to stop everything in the game scene, with only the score value being transferred to the Game Over page.

My current code to load the Game Over screen:

-(void)goGameOver
{
//Send to Game Over screen
UIStoryboard *sb = [UIStoryboard storyboardWithName:@"MainStoryboard" bundle:nil];
UIViewController *vc = [sb instantiateViewControllerWithIdentifier:@"gameOverPage"];
vc.modalTransitionStyle = UIModalTransitionStyleCrossDissolve;
[self presentViewController:vc animated:NO completion:NULL];
}

I hope my objective is clear, if not please let me know and I'll attempt to rephrase things.

Answer 1

the way that view controllers work is that they will continue to be active until they have been "popped" or "dismissed". Since you are presenting a modal view over your game page, the game page is still in memory and can continue to do things if you want it to.

One very common design pattern is that the "underneath" page - the one that created and presented the modal view controller is supposed to dismiss it via a mechanism called protocol/delegate. The only way it can do that is if its still active and because its still active - other code can also be running.

I'm not sure in your game what happens after the "game over" view is presented? Can a new game be started and if so, where do they start from? Regardless, navigation can always vary from one application to another.

One thought I had was to return to a base navigation point and present both your start page and your game over page from that controller and when your game is over, have the active view controller "pop" back to the root controller where it can present the game over view. Then this way, if you want to "start over", a simple "pop" or "dismiss" puts you right back at the beginning where you would want the game to start from.

To actually make that happen, you need a UINavigationController. Since you mentioned you were using storyboards and segues, it's pretty common to line up view controllers that are attached to a UINavigation controller.

If that is the case, you might use a flag or object to determine that game has started and use that same flag to determine its game over.

so for example, on the very first view controller in your navigation stack you might have some logic like this:

-(void)viewWillAppear:(BOOL)animated {

     if(self.gameStarted == NO){
         self.gameStarted = YES;
         [self performSegueWithIdentifier:@"startGame"];
}
else {
        self.gameStarted = NO;
        [self performSegueWithIdentifier:@"endGame"];
}

Now, you at the point where you determine the game is over, in that view controller and it should be in the navigation stack, you need to "pop" back to the first controller like this:

[self.navigationController popToRootViewControllerAnimated:YES];

I hope that idea helps in some way. It can be challenging at times to get your navigation to work the way you want it to.