CODEWITHSUNDEEP
objective-ciosmemory-management
Zhen
Zhen

Reputation: 12431

How to handle situation where page unloads due to low memory

//In App Delegate
UserProfileTableViewController *uptvc = [[UserProfileTableViewController alloc]init];
UITabBarItem *tempTabBarItem4 = [[UITabBarItem alloc]initWithTitle:@"Fans" image:nil tag:FANSTAB_INDEX];

//I am setting the user id information here directly in app delegate
uptvc.userId = [[UserStockInfo sharedUserStockInfo]getUserId];
UINavigationController *navconUptvc = [[UINavigationController alloc]initWithRootViewController:uptvc];

The problem arises when my UserProfileTableViewController gets unloaded due to low memory (might be due to using the camera feature in my app). The page will fail to load properly as it is missing the 'userId' information passed in from the app delegate (as seen above). I am unable to set this userId information directly in the UserProfileTableViewController (in view did load method) as other pages might pass a different userId when pushing the page onto their stack.

Any advise on how I can resolve this issue?

Upvotes: 0

Views: 72

Answers (1)

Psycho
Psycho

Reputation: 1883

First off, you should keep your UserProfileTableViewController object into an ivar of the app delegate (since you allocate it there). Second, make the app delegate provide that userId to the controller. Third, if the navigation controller is removed from the interface/deallocated, then even with low memory your uptvc should not be deallocated either. View controllers maintain the full hierarchy of controllers, even when running out of memory, what's deleted are views, and anything you tell them to remove.

You most certainly want to keep the UINavigationController in an ivar of the AppDelegate as well.

Upvotes: 2

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