UIScrollView Rotation Issues - iphone

Question

I have a scrollview that automatically generates a series of subviews containing imageviews. The concept is that it's pretty much a custom PDF style reader, where each page is loaded in to an imageview as an image. There are three "layers" - the outer UIScrollView, the automatically generated subViews and the imageview inside the subview.
I've been having some trouble with this, I've asked the question previously, but unfortunately, the core of my question was in the wrong place. Here is my second attempt:
On rotate, everything is rotated as needed. Unfortunately, this is what I'm getting:
Obviously, I would like Image 1 to be centred and for there to be no hint of image 2 until you flick the view across.
Here is my code for setting up the view:
- (void)loadView {
[self setUpView];
}
- (void)setUpView {
//INITIALISE PAGING SCROLL VIEW
CGRect pagingScrollViewFrame = [[UIScreen mainScreen] bounds];
pagingScrollViewFrame.origin.x -= 10;
pagingScrollViewFrame.size.width += 20;
pagingScrollView = [[UIScrollView alloc] initWithFrame:pagingScrollViewFrame];
pagingScrollView.contentMode = UIViewContentModeScaleAspectFit;
//CONFIGURE PAGING SCROLL VIEW
pagingScrollView.pagingEnabled = YES;
pagingScrollView.backgroundColor = [UIColor blackColor];
pagingScrollView.contentSize = CGSizeMake(pagingScrollViewFrame.size.width*7, pagingScrollViewFrame.size.height);
//ACTIVATE PAGING SCROLL VIEW
self.view = pagingScrollView;
//ADD PAGES TO SCROLL VIEW
for (int i = 0; i < 7; i++){
ImageScrollView *page = [[[ImageScrollView alloc] init] autorelease];
[self configurePage:page forIndex:i];
[pagingScrollView addSubview:page];
}
}
How do I re-define the size of the frame? What function should I call etc. How do I centre the image?
I'm new to this so I apologise for the ambiguity of my question.
Cheers

Answer 1

I've figured it out. It was the Frame of the individual pages that I needed to change, so (with the help gained from another question) I wrote a re-orient method.
The first step to this came because I figured out that I needed to iterate through and re-size each frame for each of my pages and then re-apply the frames to the view. For this to happen I needed to create an array which I would fill in the For Loop above. I have 7 total pages.
Then I could (on rotate) call the below re-orient method to re-size each view:
- (void) reOrient{
if(UIInterfaceOrientationIsPortrait(self.interfaceOrientation)){
CGRect f;
int i = 0;
for (ImageScrollView *page in pageArray) {
f = page.frame;
f.size.width = 320;
f.origin.x = (f.size.width * i);
page.frame = f;
pagingScrollView.contentSize = CGSizeMake(f.size.width * 7, 480);
i++;
}
}else{
CGRect f;
int i = 0;
for (ImageScrollView *page in pageArray) {
f = page.frame;
f.size.width = 480;
f.origin.x = (f.size.width * i);
page.frame = f;
pagingScrollView.contentSize = CGSizeMake(f.size.width * 7, 480);
i++;
}
}
}

Answer 2

This worked for me:
- (void)willRotateToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation duration:(NSTimeInterval)duration
{
[super willRotateToInterfaceOrientation:toInterfaceOrientation duration:duration];
//get current page based on offset before rotation
NSInteger currentPage = self.scrollView.contentOffset.x / self.scrollView.bounds.size.width;
//set anticipated scrollview content size by switching width and height (they will be switched after rotation)
[self.scrollView setContentSize:CGSizeMake(totalPages * self.view.bounds.size.height, self.view.bounds.size.width)];
//set the anticipated content offset based on height before rotation
[self.scrollView setContentOffset:CGPointMake(currentPage * self.scrollView.bounds.size.height, 0.0f)];
}
Basically I am setting the content offset for the new scrollview content size before rotating (I'm switching height and width for the anticipated height and width).
This worked for me when rotating a full-screen paged UIScrollView.
All of the paged subviews have the following autoresizing mask so that they neatly fall into place after rotation:
UIViewAutoresizingFlexibleLeftMargin | UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight | UIViewAutoresizingFlexibleRightMargin