Memory management, addSubview for a subclass of UIViewController

I have a view that shows a map. I have a custom subclass of UIViewController (DetailViewController) that gets shown when the detailDisclosureButton of the callout above the pin is开发者_如何学运维 pressed. While in my map class, I create my detailview and add it to the subview like this:

    DetailViewController *detailView = [[DetailViewController alloc] initWithNibName:@"DetailView" bundle:nil];
    detailView.locationPoint = locationPoint;
    detailView.locationCoordinate = locationCoordinate;
    [self.view addSubview:detailView.view];
    [detailView release];   

My DetailViewController has a TableView and parses the data in DetailViewController. However I get an error of sending the numberOfSectionsInTable message to a dealloc'd instance. I'm assuming it is this since I originally had this as a property and it worked fine with (nonatomic, retain). I'm assuming that I'm releasing it before the next view is done with it. If that is the case, when would I clean up the memory??? It seems like this would be the place to do it. Thanks.

I am not sure what makes you adding the view of DetailViewController into this mapviewcontroller's view. Don't you think right approach would be to either presentModalViewController or pushNavigationController?

DetailViewController *detailView = [[DetailViewController alloc] initWithNibName:@"DetailView" bundle:nil];
    detailView.locationPoint = locationPoint;
    detailView.locationCoordinate = locationCoordinate;
    //[self.view addSubview:detailView.view];
[self.navigationController pushViewController:detailView animated:YES];
//OR
[self presentModalViewController:detailView animated:YES];
    [detailView release];   

You are getting the error because you are only using the view and deallocating the view controller immediately and hence tableview datasource and delegates are hitting a nil object.

Views do not retain their view controllers. Someone needs to retain the VC or else it will get released, and then the app will crash when the view makes a call into its delegate. When you use a navigation controller, the navcon has a stack of view controllers that it retains. Likewise with presentModalViewController, the OS takes care of retaining the detail VC.

Adding a detail view as a subview is not the normal way to navigate to a new view. Instead, one either uses a navigation controller and [navcon pushViewController::], or a modal subview and [self presentModalViewController::]. If the detail view occupies only a portion of the parent view, then it is normal to retain the view controller for the subview within the parent controller. That is, within the parent VC (your map class) add a property for the detail VC. Actually, it's more common to not even use a VC for a subview, but rather for screen-filling detail views.