App is crashing when moving to other app and then moving back - ios

Question

I have an issue with my app..
It's crashing when i'm using home button for multitasking to move to another app and when i want to go back again to my app it's crashing and i get the message:
*** -[UIView convertRect:toView:]: message sent to deallocated instance 0x81e4020
It started since i've implemented "inner-view" ad's.
do i need to do something in my code to make it disspapear?
I tried to solve it but no success.
This is my code of the ad's:
CGRect frame = CGRectMake(0, 480, 320, 50);
self.adBanner = [[UIView alloc] initWithFrame:frame];
[self.view convertRect:adBanner.frame toView:nil]; --->This is a line i tried to put...
[self.view addSubview:self.adBanner];
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(iaAdReceived:) name:#"iaAdReceived" object:nil];
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(iaDefaultAdReceived:) name:#"iaDefaultAdReceived" object:nil];
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(iaAdFailed:) name:#"IaAdFailed" object:nil];
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(iaAdClicked:) name:#"IaAdClicked" object:nil];
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(iaAdWillShow:) name:#"IaAdWillShow" object:nil];
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(iaAdDidShow:) name:#"IaAdDidShow" object:nil];
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(iaAdWillHide:) name:#"IaAdWillHide" object:nil];
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(iaAdDidHide:) name:#"IaAdDidHide" object:nil];
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(iaAdWillClose:) name:#"IaAdWillClose" object:nil];
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(iaAdDidClose:) name:#"IaAdDidClose" object:nil];
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(iaAdWillResize:) name:#"IaAdWillResize" object:nil];
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(iaAdDidResize:) name:#"IaAdDidResize" object:nil];
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(iaAdWillExpand:) name:#"IaAdWillExpand" object:nil];
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(iaAdDidExpand:) name:#"IaAdDidExpand" object:nil];
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(iaAppShouldSuspend:) name:#"IaAppShouldSuspend" object:nil];
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(iaAppShouldResume:) name:#"IaAppShouldResume" object:nil];
// Display ad
if (![InneractiveAd DisplayAd:#"iOS_Test" withType:IaAdType_Banner withRoot:self.adBanner withReload:60 withParams:optionalParams])
{
[adBanner removeFromSuperview];
}
}
-(void) viewWillDisappear:(BOOL)animated
{
[super viewWillDisappear:animated];
[adBanner removeFromSuperview];
}
- (IBAction)iaAdReceived:(id)sender
{
// The ad view has finished loading a paid ad
}
- (IBAction)iaDefaultAdReceived:(id)sender
{
// The ad view has finished loading a default ad
}
- (IBAction)iaAdFailed:(id)sender
{
// The ad view has failed to load an ad
}
- (IBAction)iaAdClicked:(id)sender
{
// The ad has been clicked
}
- (IBAction)iaAdWillShow:(id)sender
{
// The ad is about to show
}
- (IBAction)iaAdDidShow:(id)sender
{
// The ad did show
}
- (IBAction)iaAdWillHide:(id)sender
{
// The ad is about to hide
}
- (IBAction)iaAdDidHide:(id)sender
{
// The ad did hide
}
- (IBAction)iaAdWillClose:(id)sender
{
// The ad is about to close
}
- (IBAction)iaAdDidClose:(id)sender
{
// The ad did close
}
- (IBAction)iaAdWillResize:(id)sender
{
// The ad is about to resize
}
- (IBAction)iaAdDidResize:(id)sender
{
// The ad did resize
}
- (IBAction)iaAdWillExpand:(id)sender
{
// The ad is about to expand
}
- (IBAction)iaAdDidExpand:(id)sender
{
// The ad did expand
}
- (IBAction)iaAppShouldSuspend:(id)sender
{
// The app should suspend (for example, when the ad expands)
}
- (IBAction)iaAppShouldResume:(id)sender
{
// The app should resume (for example, when the ad collapses)
}
I attached a screenshot...
What could it be?
Thanks...

Answer 1

Your problem is that when running :
[self.view convertRect:adBanner.frame toView:nil];
your view doesn't exists anymore.
in your appDelegate you should work on this method :
- (void)applicationDidBecomeActive:(UIApplication *)application
{
/*
Restart any tasks that were paused (or not yet started) while the application was inactive. If the application was previously in the background, optionally refresh the user interface.
*/
}
anyway, what did you try to achieve with this line ? because it's returning a CGRect which you're not using.