Question

I have a small application for displaying several UIImageViews in a UIScroller in a similar fashion to the Photo app. I have a TableView which, when i select an item, parses an XML document of photos (added to an array) and adds a UIViewController which displays the images.

The problem is I have a tab bar controller which, upon clicking a tab bar item should go back to the TableView after remove the View that displays the images and dealloc all used memory. The problem is I can’t work out how to achieve this. Whether it’s a lack of understanding the memory rules I don’t know.

Here’s the process I’m having issues with.

Table View Controller

This is called after parserDidEndDocument:. backToMenu is called from the tab bar item.

@interface AlbumsViewController : UIViewController <UITableViewDelegate, UITableViewDataSource> {
    AlbumViewController *albumViewController;
}
@property (nonatomic, retain) AlbumViewController *albumViewController;


- (void)displayPhotos {
    albumViewController = [[AlbumViewController alloc] initWithNibName:@"AlbumView" bundle:nil];

    albumViewController.parentView = self;
    albumViewController.arrPhotos = self.arrCurrentSetOfPhotos;

    [self.view addSubview:albumViewController.view];

    [albumViewController populateScroller];
}

- (void)backToMenu {
    [albumViewController.view removeFromSuperview];
}

Album View Controller

This is a UIViewController containing a UIScroller and UIPageControl. It adds several ImageViewControllers.

- (void)populateScroller {

    imagesScroller.pagingEnabled = YES;
    imagesScroller.contentSize = CGSizeMake(imagesScroller.frame.size.width * [self.arrPhotos count], 380);
    imagesScroller.showsHorizontalScrollIndicator = NO;
    imagesScroller.showsVerticalScrollIndicator = NO;
    imagesScroller.scrollsToTop = NO;
    imagesScroller.delegate = self;
    imagesScroller.backgroundColor = [UIColor blackColor];

    pageControl.numberOfPages = [self.arrPhotos count];
    pageControl.currentPage = 0;
    pageControl.backgroundColor = [UIColor blackColor];

    NSMutableArray *controllers = [[NSMutableArray alloc] init];
    for (int i = 0; i < [self.arrPhotos count]; i++) {

        CGRect frame = imagesScroller.frame;
        frame.origin.x = frame.size.width * i;
        frame.origin.y = 0;

        NSString *strImagePath = [self.arrPhotos objectAtIndex:i];

        ImageViewController *imageViewController = [ImageViewController alloc];
        imageViewController.localImage = YES;
        [imageViewController initWithPhotoName:strImagePath];
        [controllers addObject:imageViewController];

        imageViewController.view.frame = frame;
        [imagesScroller addSubview:imageViewController.view];

        [imageViewController release];

    }

    self.viewControllers = controllers;
    [controllers release];

}

ImageViewController

This has one method. It adds an subclassed UIView called ImageView which handles adding a UIImageView.

- (void)loadImage {

    NSString *strRootURL = @"http://www.marklatham.co.uk";

    CGRect rect = CGRectMake(0.0, 0.0, 320.0, 480.0);

    ImageView *imageView = [ImageView alloc];
    imageView.strURL = [strRootURL stringByAppendingString:self.strThisPhoto];
    imageView.strTmpPrefix = (self.localImage) ? @"_tmp_rockphotothumb_" : @"_tmp_rockphotolarge_";
   [imageView initWithFrame:rect];

   [self.view addSubview:imageView];

   [imageView release];
}

The backToMenu function is supposed to remove/dealloc AlbumViewController and call delloc on ALL child subviews freeing up the used memory.

Where am going wrong? Any help would be appreciated.

Thanks.

Answer 1

After convincing my client I managed to get around this by going with the three20 framework.