Question

I am trying to save my data from a view that was loaded on applicationWillTerminate but am running into a few problems.

I have four views:
inFinateViewController
FirestViewController
SecondViewController
ThirdViewController

I am loading my views from like this (thanks to Mauricio Giraldo code) via the infinateViewController:

- (void) displayView:(int)intNewView {

NSLog(@"%i", intNewView);   

[self.currentView.view removeFromSuperview];
[self.currentView release];
switch (intNewView) {
    case 1:
        self.currentView = [[FirstViewController alloc] initWithNibName:@"FirstView" bundle:nil];
        break;
    case 2:
        self.currentView = [[SecondViewController alloc] initWithNibName:@"SecondView" bundle:nil];
        break;
    case 3:
        self.currentView = [[ThirdViewController alloc] initWithNibName:@"ThirdView" bundle:nil];
        break;
}

[self.view addSubview:self.currentView.view];

CATransition *animation = [CATransition animation];
[animation setDelegate:self];
[animation setType:kCATransitionReveal]; 
[animation setDuration:0.75];
[animation setTimingFunction:[CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut]]; 
[[self.currentView.view layer] addAnimation:animation forKey:kCATransition];

}

And it starts up via:

- (void)viewDidLoad {
self.currentView = [[FirstViewController alloc]
               initWithNibName:@"FirstView" bundle:nil];
[self.view addSubview:self.currentView.view];
[super viewDidLoad];
}

In my SecondViewController, I have a NSMutableArray that on start, I initialize with numbers, scramble them, and then use. My goal is to save these entries when the applicationWillTerminate is called.

In my SecondViewController I also have a method that has:

-(void) saveExitData
{
[pnames writeToFile:[self saveFilePath: @"gameArrayData.plist"] atomically:YES];

 }

My problem is that the applicationWillTerminate is in the appDelegate and although I am calling it, it does not seem to run. I attempted to step into it via debugger, but it only hits it and never jumps into it. Code is:

- (void)applicationWillTerminate:(UIApplication *)application {
[secondViewController saveExitData];

} 

My infinateViewsAppDelegate looks like this:

//  InfiniteViewsAppDelegate.h
#import <UIKit/UIKit.h>
@class SecondViewController;
@class InfiniteViewsViewController;

@interface InfiniteViewsAppDelegate : NSObject <UIApplicationDelegate> {
UIWindow *window;
InfiniteViewsViewController *viewController;
SecondViewController  *secondViewController;

}

@property (nonatomic, retain) IBOutlet UIWindow *window;
@property (nonatomic, retain) IBOutlet InfiniteViewsViewController *viewController;
@property (nonatomic, retain) IBOutlet SecondViewController *secondViewController;

-(void) displayView:(int)intNewView;

@end

and the .m File:

//  InfiniteViewsAppDelegate.m
#import "SecondViewController.h"
#import "InfiniteViewsAppDelegate.h"
#import "InfiniteViewsViewController.h"

@implementation InfiniteViewsAppDelegate

@synthesize window;
@synthesize viewController;
@synthesize secondViewController;

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {

[window addSubview:viewController.view];

[window makeKeyAndVisible];

return YES;
 }

- (void)displayView:(int)intNewView {
[viewController displayView:intNewView];
}

- (void)dealloc {
[viewController release];
[window release];
[super dealloc];
}


@end

So, I guess my question is, how would I be able to save this data? Can the applicationWillTerminate be placed in my SecondViewController so I could write the data and save from there? Or does applicationWillTerminate only exist in the appDelegate?

Thanks to anyone who can shed some light on this. I have read books upon books and googled forever…but still no answer.

Geo…

Answer 1

If your app delegate is set up correctly, applicationWillTerminate: should definitely be called. You should investigate this because if it isn’t, you have an error somewhere.

It’s not necessary to solve your problem, though: besides applicationWillTerminate:, the UIApplication instance will also send out a notification named UIApplicationWillTerminateNotification on exit. You can have your view controllers observe this notification and then there is no need for your app delegate to maintain a reference to your view controllers.

When a view controller is created, have it register for the notification:

[[NSNotificationCenter defaultCenter] addObserver:self 
                                         selector:@selector(applicationWillTerminateNotification:)
                                             name:UIApplicationWillTerminateNotification
                                           object:[UIApplication sharedApplication]];

The notification center will then call the selector you specified and you can save your stuff in that method:

- (void)applicationWillTerminateNotification:(NSNotification *)notification {
    // save stuff ...
}

Don’t forget to unregister yourself when the view controller is deallocated:

[[NSNotificationCenter defaultCenter] removeObserver:self 
                                                name:UIApplicationWillTerminateNotification 
                                              object:[UIApplication sharedApplication]];