Paging in UIScrollView broken in iPad 3.2?

[krye]

Finally got my hands on an iPad and just noticed now that my UIScrollvew is corrupted in one of my apps when you scroll left or right. It works fine on iPhone 3.1.3. But it broken on the iPad. Need to fix this fast since it's on the store.

It has something to do with Paging and Bounce Scroll being checked off in IB. I disabled them and it's OK now, but I'm left without paging.

Anyone found a way to fix it?

[krye]

Originally Posted by krye

Finally got my hands on an iPad and just noticed now that my UIScrollvew is corrupted in one of my apps when you scroll left or right. It works fine on iPhone 3.1.3. But it broken on the iPad. Need to fix this fast since it's on the store.

It has something to do with Paging and Bounce Scroll being checked off in IB. I disabled them and it's OK now, but I'm left without paging.

Anyone found a way to fix it?

Wow, haven't been able to find an answer to this. I wonder if it is a bug?

[Ray9s]

Yeah, I've been having issues with scrollview in 3.2 as well. Just figured I was doing something wrong. Hopefully someone has some insight.

[wojtkow]

I have this same problem, in typical:

- (void)scrollViewDidEndDragging:(UIScrollView *)scrollView willDecelerate:(BOOL)decelerate {
	CGFloat pageWidth = scrollView.frame.size.width;
    int page = floor((scrollView.contentOffset.x - pageWidth / 2) / pageWidth) + 1;
}

I have crazy results, because scrollView.contentOffset.x always returns 0.

[linkmx]

Weird, I'm using a scrollview with paging on the iPad and I haven't had any problems.

[wojtkow]

Can you post how you create UIScrollView?
There is my code:

- (void)layoutScrollImages {
	
	int imageWidth = (PMI_MINIATURE_WIDTH + PMI_MARGIN_LEFT +PMI_MARGIN_RIGHT);
	int popr = ([scrollView bounds].size.width -imageWidth) /2;
	
	UIImageView *view = nil;
	NSArray *subviews = [scrollView subviews];

	// reposition all image subviews in a horizontal serial fashion
	CGFloat curXLoc = popr;
	for (view in subviews)
	{
		if ([view isKindOfClass:[ProjectImageView class]] && view.tag > 0)
		{
			CGRect frame = view.frame;
			frame.origin = CGPointMake(curXLoc, 0);
			view.frame = frame;
			
			curXLoc += (imageWidth +popr*2);
		}
	}
	
	// set the content size so it can be scrollable
	int size = dataArray.count * (imageWidth +2*popr);
	[scrollView setContentSize:CGSizeMake(size, scrollView.bounds.size.height)];



}

- (void)createView {
	if (self.dataArray != nil) {
		for (int i=0; i<self.dataArray.count; i++) {
			Project *project = (Project *)[self.dataArray objectAtIndex:i];
			UIImage *image = [UIImage imageWithData:project.miniature];
			ProjectImageView *imageView = [[ProjectImageView alloc] initWithImage:image];
			[imageView setDelegate:self];
			[imageView setImageName:project.projectName];

			imageView.tag = i+1;	// tag our images for later use when we place them in serial fashion
			imageView.userInteractionEnabled = YES;
			[scrollView addSubview:imageView];
			[imageView release];
		}
		
	}	
}

- (void)viewDidLoad {
    scrollView = [[UIScrollView alloc] initWithFrame:CGRectMake(20, 67, 728, 680)];
    scrollView.pagingEnabled = YES;
    scrollView.backgroundColor = [UIColor clearColor];
    scrollView.showsHorizontalScrollIndicator = NO;
    scrollView.showsVerticalScrollIndicator = NO;
    scrollView.scrollsToTop = NO;
    scrollView.delegate = self;
    scrollView.userInteractionEnabled = YES;
	
    [self.view addSubview:scrollView];

    [self createView];
    [self layoutScrollImages];
}

[hveveris]

I think the same or a similar bug is described here: Bynomial Code UIScrollView bug . Ran into the same problem when tried to custom animate UIScrollView after didEndDragging event.
SDK 3.1.3 was fine - this appeared starting from sdk 3.2

[bshirley]

I was having a problem with my scroll view in iPad as well.
Often the pages were being set half-way through.
I am also customizing some of the movement inside the scroll view.

I was setting the contentOffset at launch.
This caused scrollViewDidScroll: to be called.

though the frame said it was 960 wide, the standardOffset value below was being set to 480, i removed my superstitious casting of these values and the value went back to 960,

the processing that was being performed depending upon offset i think was all of my issues,

CGUInteger offset = [scrolledView contentOffset].x;
CGUInteger standardOffset = (CGUInteger)[scrolledView frame].size.width;

CGFloat offset = [scrolledView contentOffset].x;
CGFloat standardOffset = [scrolledView frame].size.width;


my suggestion, break in scrollViewDidScroll: and look for problems