UIViewcontroller dealloc not being called

[sheisdig]

My app has a main UIViewController that loads a custom UIViewController for each screen in my app.

Its a linear experience, so the main controller loads the 1st screen. Then, when the player clicks a button, it loads the 2nd screen and releases the 1st one. For some reason, one of the UIViewControllers is being retained and so even though I'm releasing it, dealloc is not being called. I've seen several similar posts, but no clear solution. I have read all of the articles related to NIB files and memory management. I'm not sure I understand completely, but I can see no difference in how I am instantiating the UIViewController that isn't getting the dealloc call.

I would appreciate any suggestions.

Here is the header for my main controller:

#import <UIKit/UIKit.h>

@class JoinViewController;
@class LoginViewController;

@interface SwitchViewController : UIViewController {
	JoinViewController *joinViewController;
	LoginViewController *loginViewController;
}

@property (retain, nonatomic) JoinViewController *joinViewController;
@property (retain, nonatomic) LoginViewController *loginViewController;

- (void)initJoinView;
- (void)initLoginView;
- (void)launchLogin:(UIViewController *)sender;
- (void)launchGame:(UIViewController *)sender;

@end

Here is the implementation file for the main controller:

- (void)initJoinView {
	joinViewController = [[JoinViewController alloc] initWithNibName:@"JoinView" bundle:nil];
	self.joinViewController.rootWindowRef = self;
	[self.view insertSubview:joinViewController.view atIndex:0];
}

- (void)initLoginView {
	loginViewController = [[LoginViewController alloc] initWithNibName:@"LoginView" bundle:nil];
	loginViewController.rootWindowRef = self;
    [self.view insertSubview:loginViewController.view atIndex:0];
	[self.loginViewController displayPref:self.prefObj];
}

- (void)launchLogin:(UIViewController *)sender {
	[self initLoginView];
	[[joinViewController view] removeFromSuperview]; 
	[joinViewController release]; 
}


- (void)launchGame:(UIViewController *)sender {
	[self initGameView];
	[[loginViewController view] removeFromSuperview];
	[loginViewController release];
}

The loginViewController gets the dealloc message. The joinViewController does not.

For fun, I reversed the order and loaded the loginViewController first and the
joinViewController second. Same results.

[sheisdig]

I figured it out - I was setting UIView animation delegate which prevented the view from being released.

[caleboller]

I'm having a similar issue, using a pair of custom buttons to go from a UIView to UITableViews, could you clarify how you corrected the issue?

Thanks!

[caleboller]

Update: Figured it out. Thanks

[sheisdig]

The issue had to do with IBOutlets within UIViewControllers. I resolved my issue by adding this method:

-(void)setView:(UIView*)aView {
	if (!aView){
		//set outlets to nil here
		self.scrollView = nil;
		self.joinButton = nil;
		self.activityProgress = nil;
		self.numPlayersLabel = nil;
		self.numPlayersText = nil;
		self.timeView = nil;
		self.timeLabel = nil;
	}
	[super setView:aView];
}

And then in your dealloc method, release IBOutlets and set to nil.

- (void)dealloc {
	[scrollView release], scrollView = nil;
	[joinButton release], joinButton = nil;
	[activityProgress release], activityProgress = nil;
	[numPlayersLabel release], numPlayersLabel = nil;
	[numPlayersText release], numPlayersText = nil;
	[timeView release], timeView = nil;
	[timeLabel release], timeLabel = nil;
        [super dealloc];
}

I think I also may have had an IBOutlet instance that I didn't actually declare as an outlet in my header file.

Hope that helps.

[mga]

I have a similar situation to yours. I have managed to get the dealloc to fire but the nib is still around taking up memory. What am I missing?

I have a more detailed question (with code and all) posted here: iphone app with multiple views/subviews: memory is not being deallocated - Stack Overflow

[cheyengu]

I have a simple view controller that is switching to another view controller. When the switch occurs the dealloc method of the current view controller is not being called. I cannot see any references being left open. Note: Item is a core data object.

header file:

#import <UIKit/UIKit.h>

@interface AddCollectionViewController : UIViewController {
	IBOutlet UITextField *tfCollection;
	IBOutlet UITextField *tfYear;
	NSManagedObjectContext *managedObjectContext;
}

@property (nonatomic, retain) UITextField *tfCollection;
@property (nonatomic, retain) UITextField *tfYear;
@property (nonatomic, retain) NSManagedObjectContext *managedObjectContext;

-(IBAction) btnClicked: (id) sender;
-(IBAction) cancelClicked: (id) sender;
-(void)insertNewObject;

@end

implementation:

#import "AddCollectionViewController.h"
#import "CollectionListViewController.h"
#import "Collection.h"

@implementation AddCollectionViewController

@synthesize tfCollection,tfYear,managedObjectContext;

-(IBAction) btnClicked:(id) sender {
	[self insertNewObject];

	CollectionListViewController *viewController = [[CollectionListViewController alloc] initWithNibName:@"CollectionListViewController" bundle:nil];
	viewController.managedObjectContext = [[UIApplication sharedApplication].delegate managedObjectContext]; 
	[self.navigationController pushViewController:viewController animated:YES];
	[viewController release];
}

-(IBAction) cancelClicked:(id) sender {
	CollectionListViewController *viewController = [[CollectionListViewController alloc] initWithNibName:@"CollectionListViewController" bundle:nil];
	viewController.managedObjectContext = [[UIApplication sharedApplication].delegate managedObjectContext];
	[self.navigationController pushViewController:viewController animated:YES];
	[viewController release];
}


#pragma mark -
#pragma mark Add a new object

- (void)insertNewObject {
	NSEntityDescription *entity = [NSEntityDescription entityForName:@"Collection" inManagedObjectContext:managedObjectContext];
	Collection *coll = (Collection*)[NSEntityDescription insertNewObjectForEntityForName:[entity name] inManagedObjectContext:managedObjectContext];
	
	coll.name = tfCollection.text ;
	coll.year = tfYear.text ;
	
	// Save the context.
    NSError *error = nil;
    if (![managedObjectContext save:&error]) {
		NSLog(@"Unresolved error %@, %@", error, [error userInfo]);
		abort();
    }
}

- (void)didReceiveMemoryWarning {
	// Releases the view if it doesn't have a superview.
    [super didReceiveMemoryWarning];
	
	// Release any cached data, images, etc that aren't in use.
}

- (void)viewDidUnload {
	NSLog(@"AddCollectionViewController: viewDidUnload");
	self.tfCollection = nil ;
	self.tfYear = nil ;
}


- (void)dealloc {
	NSLog(@"In dealloc for AddCollectionViewController");
	[tfCollection release];
	[tfYear release];
	[managedObjectContext release];
    [super dealloc];
}


@end