App crashes when releasing a view properly

Question

Hope you can help me with this problem. I am having issues with the following code:

-(IBAction)swapViews:(id)sender{
    myappAppDelegate *delegate = (myappAppDelegate *) [[UIApplication sharedApplication] delegate];
    ThirdViewController *thirdView = [[ThirdViewController alloc] initWithNibName:@"ThirdViewController" bundle:nil];
    [delegate switchView:self.view toView:thirdView.view];
    [thirdView release];
}

As you can see I allocated my ViewController and released it afterwards. The problem is that when i change views to my ThirdViewController and then want to get back to the previous view, the app crashes. This is how i get back to my previous view:

-(IBAction)goBack:(id)sender{
    myappAppDelegate *delegate = (myappAppDelegate *) [[UIApplication sharedApplication] delegate];
    FirstViewController *firstView = [[FirstViewController alloc] initWithNibName:@"FirstViewController" bundle:nil];
    [delegate switchView2:self.view toView:firstView.view];
    [firstView release];
}

Again the same problem when releasing the View. If I don't release the views the app won't crash but there are lots of memory leaks and taking into account I have over 15 ViewControllers, the app will eventually crash if I use it for a long time.

Any ideas what am I doing wrong? ps: I am using a delegate for the animation/transition of the view.

Thanks!

Edit: switchView:toView: code below

-(void)switchView:(UIView *)view1 toView:(UIView *)view2 {
    [UIView beginAnimations:@"Animation" context:nil];
    [UIView setAnimationDuration:0.75];
    [UIViewsetAnimationTransition:UIViewAnimationTransitionCurlUp forView:self.window cache:YES];
    [view1 removeFromSuperview];
    [window addSubview:view2];
    [UIView commitAnimations];

}

Please use 4 spaces for every code line. HTML code tags aren't supported (well). ;-) — Constantino Tsarouhas, Jun 24 '11 at 14:26
What does [myappAppDelegate switchView:] do? And [... switchView2:]? — onnoweb, Jun 24 '11 at 14:27

score 1 · Accepted Answer · answered Jun 24 '11 at 14:34

1

Don't want to sound like Mr. Obvious, but unless the view switched to is being retained in your delegate before its controller is released, you're operating on a released view before switching back, hence the crash.

It would be probably better if your switchView:toView methods operated on UIViewControllers, not just UIViews. Then you can retain the viewController whose view you need, and release it when it's not needed any more.

But for now that's all we can take from your current problem description. Show the code of switchView:toView: and switchView2:toView: methods, and the crash log and we'll go from there.

answered Jun 24 '11 at 14:34

macbirdie

16,086
6
47
54

Thanks For answering! myappAppDelegate switchView:toView has the following code and it is used to create the transition effect. switchView2 has the same code, only instead of TransitionCurlUp -> TransitionCurlDown `-(void)switchView:(UIView *)view1 toView:(UIView *)view2{ [UIView beginAnimations:@"Animation" context:nil]; [UIView setAnimationDuration:0.75]; [UIViewsetAnimationTransition:UIViewAnimationTransitionCurlUp forView:self.window cache:YES]; [view1 removeFromSuperview]; [window addSubview:view2]; [UIView commitAnimations]; } ` – Andres Jun 24 '11 at 14:49
Yes, you retain the view (via addSubview:) but not the controller himself ! – Johnmph Jun 24 '11 at 15:31
Thanks for pointing that out. I'm fairly new to this. So I should retain the UIViewController, not just the UIView? If yes, what is the best way to do it? – Andres Jun 24 '11 at 16:05
You should already have a UIViewController member in your appDelegate, so change switchView:toView method into switchViewController:toViewController. Before doing the transition retain the new Controller, set it to the member, release the current one and you should be fine. – macbirdie Jun 24 '11 at 21:10
Thank you all guys. That was exactly the issue I had. So after switching there, retaining over there and releasing somewhere else, my app works like a charm now. I am able now to release all allocated views without crashing it and of course with ZERO memory leaks. Im new here, how should I accept an answer? – Andres Jun 26 '11 at 18:55
Just click the checkmark button below question votes count. Thanks! – macbirdie Jun 26 '11 at 19:19

App crashes when releasing a view properly

1 Answers1