How to release a view when it's not visible in a tabbar controller?

Question

I have a simple app with a tabbar navigation interface. It has three view (A, B and C) and a modal view. Each view has its own view controller and nib . They are all designed and connected in the interface builder.

I'd like to release views which are not visible. Tried release and nil them when another view appears such as

[[[self.navigationController.viewControllers objectAtIndex:0] view] release];       
[[self.navigationController.viewControllers objectAtIndex:0] view] = nil;

etc.

It doesn't cause any issues but when I run instruments it does not make any difference. I don't see any drop in memory usage

I would appreciate your help

Answer 1

The drop in memory usage might not be significant, depending on what the released viewController holds on to. I sugest you out a NSLog into the 'dealloc' of the viewController to see if it really gets dealloced or if there is some other object still holding on to it. Remember that release won't free the memory, it will only do so (by calling dealloc) if the objects retain count reached 0.

Answer 2

You don't want to do this. Let the TabBarController handle your view controllers for you. (It will already retain your viewController internally so whatever you do will only make retain count go out of sync)

You may be able to make it more memory efficient if you release objects in viewWillDisappear. Then rebuild the data again in viewWillAppear.

Answer 3

as @Daryl Teo wrote you should release and recreate in viewWillDis/Appear and (thats why I write this answer) you have a method called didReceiveMemoryWarning , use it!
You can simply log out whenever it gets called and test it with the Simulator included memory warning test function.
Simply open a tab, open another tab and call that test function. Your debug console should print out the log. If not you should double check if you have released all objects maybe someone is over-retained (which again should be released in viewWillDisappear ).