A Completed Game: Belt Commander - Beginning iOS6 Games Development - page 273

In Listing 12-4, we see the task alertView:clickedButtonAtIndex: , which is defined by the protocol
UIAlertViewDelegate and implemented by RootViewController . In this task, we first check which
UIAlertView was clicked.
If alertView is equal to pauseGameAlertView , then we know that the user has clicked the Pause button
on the Game view and is responding to the dialog that is presented. If the user clicks Yes on the
dialog ( buttonIndex == 0 ), then the user wants to exit the current game. We call endOfGameCleanup
and popViewControllerAnimated: ; the latter, of course, returns us to the Start view. The task
endOfGameCleanup is responsible for reporting on the social media services, and we will look at
it shortly. If the user had clicked No, we simply unpause the game by calling setIsPaused : and
beltCommanderController and pass in NO .
In Listing 12-4, there are two possible UIAlertViews that might be responsible for
alertView:clickedButtonAtIndex: being called. We looked at the case for the UIAlertView
pauseGameAlertView ; the other option is that the newGameAlertView is responsible. This UIAlertView
is displayed at the end of a game when the user's ship has lost all of its health. This dialog allows the
user to simply start a new game or return to the Start view. As can be seen, starting a new game is
as simple as calling doNewGame: on beltCommanderController . To return to the Start view, we use the
now familiar task popViewControllerAnimated: .
The code responsible for displaying the two different UIAlertView is very similar; let's just look at one
of those to understand it. The code that displays the UIAlertVIew at the end of a game is shown in
Listing 12-5.
Listing 12-5. RootViewController.m (gameOver:)
-(void)gameOver:(BeltCommanderController*)aBeltCommanderController{
if (newGameAlertView == nil){
newGameAlertView = [[UIAlertView alloc] initWithTitle:@"Your Game Is
Over." message:@"Play Again?" delegate:self cancelButtonTitle:@"Yes"
otherButtonTitles:@"No", nil];
}
[newGameAlertView show];
[self endOfGameCleanup];
}
In Listing 12-5, we see the task gameOver: as implemented by RootViewController . The task
gameOver: is defined by the protocol BeltCommanderDelegate , which is the delegate protocol used
to communicate between the RootViewController and the BeltCommanderController when a game
starts or stops. That is to say, the RootViewController is a delegate of beltCommanderView . This
relationship is defined in the XIB file. In this case, we are looking at the code that is called when the
game is over. In this task, we lazily create the UIAlertView newGameAlertView , specifying the text to
be displayed and that self should be used as the delegate. To display the UIAlertView we call show ,
causing the view to pop up on the user's screen. The last thing we do is call endOfGameCleanup , as
shown in Listing 12-6.