Heap memory is growing

[iph_s]

Today I made some tests and I am curious of the results. I made an app (ARC) which have UINavigationController and two UIViewControllers. In the first view there is a button and when that button is pressed the second view is loaded. In the second view when shake gesture is detected the first view is loaded and so on. What I notice in instruments is that the heap grows every time when a view is loaded. Here is some code

AppDelegate.m

self.navigationController = [[UINavigationController alloc]init];
self.window setRootViewController:self.navigationController];
FirstViewController *firstview = [FirstViewController alloc]init];
[self.navigationController pushViewController:FirstViewController animated:YES];

FirstViewController.m

-(IBAction)loadSecondView
{
  SecondViewController *secondview = [SecondViewController alloc]init];
  [self.navigationController pushViewController:secondview animated:YES];
}

SecondViewController.m

-(IBAction)loadFirstView
{
  FirstViewController *firstview = [FirstViewController alloc]init];
  [self.navigationController pushViewController:first view animated:YES];
}

I can't figure out why that happens. How to avoid heap of growing in that case ?

[gmarro]

Originally Posted by iph_s

FirstViewController.m

-(IBAction)loadSecondView
{
  SecondViewController *secondview = [SecondViewController alloc]init];
  [self.navigationController pushViewController:secondview animated:YES];
}

SecondViewController.m

-(IBAction)loadFirstView
{
  FirstViewController *firstview = [FirstViewController alloc]init];
  [self.navigationController pushViewController:first view animated:YES];
}

I can't figure out why that happens. How to avoid heap of growing in that case ?

You are pushing second view over first view over second view over first view.... etc.

In SecondViewController you have to POP the view with popViewControllerAnimated:

Then your second view and secondViewController are both released.

[iph_s]

I did what you suggested. Here is the result of instruments. I made every snapshot while switching between the views.



It think the memory is still growing. Am I right ?

[gmarro]

Originally Posted by iph_s

I did what you suggested. Here is the result of instruments. I made every snapshot while switching between the views.

It think the memory is still growing. Am I right ?

Can you show me the new code in SecondViewController?

Have you deleted the alloc of a new FirstViewController? You don't need it now that you are popping.

[iph_s]

FirstView.m

    SecondView *secondview = [[SecondView alloc]init];
    [self.navigationController pushViewController:secondview animated:YES];

SecondView.m

FirstView *firstview = [[FirstView alloc]init];
[self.navigationController popViewControllerAnimated:YES];
[self.navigationController pushViewController:firstview animated:YES];

[Duncan C]

Originally Posted by iph_s

FirstView.m

    SecondView *secondview = [[SecondView alloc]init];
    [self.navigationController pushViewController:secondview animated:YES];

SecondView.m

FirstView *firstview = [[FirstView alloc]init];
[self.navigationController popViewControllerAnimated:YES];
[self.navigationController pushViewController:firstview animated:YES];

No. Not right. A navigation controller presents a stack of view controllers. When you push a view controller, the current view controller gets covered up by the new one, but sticks around. In order to go back to the previous view controller, just pop the new view controller off the top of the stack, without creating anything. The old view controller will still be there, and will be revealed.

[gmarro]

Please, modify your secondView.m file:

SecondView.m

[self.navigationController popViewControllerAnimated:YES];

[/quote]

Thats all. You only have to remove the other lines.