How to retain superview when adding a subview to it in iphone? - iphone

Question

I had an application in which i am having a view controller which is an appdelegate instance.I am adding that view to the self.navigationcontrollers view in order to place it above navigation bar.lke this `
if(appDelegate.viewcontroller==nil)
{
appDelegate.viewcontroller = [[ViewController alloc] init];
[self.navigationController.view addSubview:appDelegate.viewcontroller.view];
NSLog(#"My view frame: %#", NSStringFromCGRect(appDelegate.viewcontroller.view.frame));
appDelegate.viewcontroller.view.tag=7;
appDelegate.viewcontroller.view.frame =CGRectMake(0,480,300,460);
[UIView animateWithDuration:.50
animations:^{
appDelegate.viewcontroller.view.frame =CGRectMake(0,30,300,440);
}];
[appDelegate.viewcontroller viewWillAppear:YES];
}
else
{
NSLog(#"My view frame: %#", NSStringFromCGRect(appDelegate.viewcontroller.view.frame));
appDelegate.viewcontroller.view.frame=CGRectMake(0, 30,300, 440);
[self.navigationController.view addSubview:appDelegate.viewcontroller.view];
appDelegate.viewcontroller.view.frame =CGRectMake(0,480,300,460);
[UIView animateWithDuration:.50
animations:^{
appDelegate.viewcontroller.view.frame =CGRectMake(0,30,300,440);
}];
[appDelegate.viewcontroller viewWillAppear:YES];
}
...Now i am adding another viewcontrollers view in to this view by
contactphoneForAddfriend= [[EventsViewController alloc]initWithNibName:#"EventsViewController" bundle:nil];
contactphoneForAddfriend.orgarray=self.eventsArray;
[UIView beginAnimations:#"View Flip" context:nil];
[UIView setAnimationDuration:0.80];
[UIView setAnimationCurve:UIViewAnimationCurveEaseInOut];
[UIView setAnimationTransition:
UIViewAnimationTransitionFlipFromRight
forView:self.view cache:NO];
[self.view addSubview:contactphoneForAddfriend.view];
[UIView commitAnimations];
` and then from that view controller when i am going in to the background of the application ...that appdelegate viewcontroller is showing as nil.How come this happen.after all its an appdelegate variouble.when i remove he added view and then go background it is there.Can anybody point me in where i am going wrong?

Answer 1

Checked you code.And found viewController is not nil.Check yourself by applying some code in this method
- (void)applicationDidEnterBackground:(UIApplication *)application
{
if (self.viewController==nil) {
NSLog(#"ViewController is nil");
}else{
NSLog(#"ViewController Has value %#",NSStringFromClass([self.viewController class]));
}
}