Can't transition to Level 2 (using UINavigationController) - ios

Question

In my GameViewController class, I have this method displayWinScreen which gets the current level number and stores it in a public property in my WinViewController class called levelCompleted. It then runs this method called runPushAnimationWithController: which just pushes the WinViewController object onto the UINavigation stack.
- (void)displayWinScreen {
WinViewController *winViewController = [[WinViewController alloc] initWithNibName:#"WinViewController"
bundle:nil];
winViewController.levelCompleted = self.levelNumber;
[self runPushAnimationWithController:winViewController];
}
Then in WinViewController I set a button that, when pressed on the iPhone, calls this method:
-(IBAction)nextLevelSelection:(id)sender {
int num = [self.levelCompleted integerValue];
int newNum = num + 2;
self.levelCompleted = [NSNumber numberWithInteger:newNum];
GameViewController* nextLevelViewController = [[GameViewController alloc]
initWithNibName:#"GameViewController"
bundle:nil];
nextLevelViewController.levelNumber = self.levelCompleted;
[self runPushAnimationWithController:nextLevelViewController];
}
This method just increases that property value, and stores it in the GameViewController property levelNumber. When I put a breakpoint to see if that int number gets passed, everything checks out. If I originally played level 3, the number that eventually is nextLevelViewController.levelNumber is 4. Ignore the num + 2, the way I have it set up, the int value still will the increase the level by 1.
I use this same process of passing int properties for all my other UINavigationController methods and everything is ok. Except for this. Should I popping the controller or use another technique for view controller transitioning?
Here's the pop method I use to go back to the GameViewController from WinViewController.
-(void)runPopperAnimation:(UIViewController*)viewController {
CATransition *transition = [CATransition animation];
transition.duration = 0.30f;
transition.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut];
transition.type = kCATransitionFade;
[self.navigationController.view.layer addAnimation:transition forKey:nil];
[self.navigationController popToViewController:viewController animated:NO];
}

Answer 1

how would I be able to pass that levelCompleted property from the
WinViewController back up to the GameViewController?
One way is to store it to a separate singleton class:
DataModel.h
#interface DataModel : NSObject
#property NSInteger *levelCompleted;
+ (id)sharedModel;
DataModel.m
#import "DataModel.h"
#implementation DataModel
#synthesize levelCompleted;
/* Return singleton model */
+ (id)sharedModel {
static DataModel *sharedModel = nil;
static dispatch_once_t onceToken;
dispatch_once(&onceToken, ^{
sharedModel = [[self alloc] init];
});
return sharedModel;
}
- (id)init {
self = [super init];
if (self){
self.levelCompleted = 0;
return self;
}
You can then call this class from anywhere in your code and modify it's properties:
NSInteger levelCompleted = [DataModel sharedModel].levelCompleted;
To increment the value:
[DataModel sharedModel].levelCompleted+=1;
With this method, the levelCompleted will only persist over the lifecycle of the app execution. If you restart the device or close the app, the value is lost.
BUT
If you want to persist across restarts then you can save it to NSUserDefaults instead. This will persist of the lifetime of the app install:
NSUserDefaults *standardUserDefaults = [NSUserDefaults standardUserDefaults];
To Retrieve the value:
NSNumber *levelCompleted =[standardUserDefaults objectForKey:#"levelCompleted"];
To Save the value:
[stadardUserDefaults setObject:levelCompleted forKey:#"levelCompleted"];