如何从 UIScrollView 中卸载 UIViewController？

Question

I am using pretty much the same code to load my UIViewController (called LessonScrollView) into the UIScrollView. The method is called when in the scrollViewDidScroll method

- (void)loadScrollViewWithPage:(int)page {

if (page < 0)
    return;
if (page >= numPages)
    return;

LessonScrollView *controller = [imageViewControllers objectAtIndex:page];
if ((NSNull *)controller == [NSNull null]) {
    controller = [[LessonScrollView alloc] initWithPage:page forLesson:[self title]];
    [imageViewControllers replaceObjectAtIndex:page withObject:controller];
    [controller release];
}

if (controller.view.superview == nil) {
    CGRect frame = CGRectMake(0, 80, 320, 285);
    frame.origin.x = frame.size.width * page;
    frame.origin.y = 0;
    controller.view.frame = frame;
    [scrollView addSubview:controller.view];
}

}

In some circumstances I have quite a few pages, which I believe, remain in memory until the UIViewController responsible for the scrollView is released (or a memory warning occurs).

My question is, how would I release the LessonScrollView object. I would call a method called, say

- (void)unloadScrollViewWithPage:(int)page 

in scrollViewDidScroll and page would be the current page - 1.

Thanks for any help you can offer.

Answer 1

Try this:

[controller.view removeFromSuperview];//to release the controller's view
[imageViewControllers replaceOjectAtIndex:page withObject:[NSNull null]];//to release the actual controller which should lead to it being dealocated