Question

I have an application which has a fullscreen UIScrollView, and within it there are seven images. The images are also meant to be full screen, and the scroll view is set to enable pagination.

I have a method which either creates or moves the image views:

-(void)rebuildImageView{

    // set up images
    float screenW = self.view.bounds.size.width;
    float screenH = self.view.bounds.size.height;
    int numImgs = self.soundNames.count;

    self.mainScrollView.contentSize = CGSizeMake(screenW * numImgs, screenH);
    for(int i=0; i<numImgs; i++){

        UIImageView* imageView = (UIImageView*)[self.mainScrollView viewWithTag:i+100];
        if(imageView == nil){
            imageView = [[UIImageView alloc] init];
            imageView.tag = i+100;
            [self.mainScrollView addSubview:imageView];
            imageView.image = [UIImage imageNamed:[NSString stringWithFormat:@"image%d.jpg",i]];
            imageView.contentMode = UIViewContentModeScaleAspectFill;
            imageView.clipsToBounds = YES;
            [imageView release];
        }
        imageView.frame = CGRectMake(i * screenW, 0, screenW, screenH);
    }

    // scroll to the current one
    [self.mainScrollView scrollRectToVisible:CGRectMake(self.currentSound*screenW, 0, screenW, screenH) animated:YES];
}

I also have this on the view controller:

-(void)willAnimateRotationToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation duration:(NSTimeInterval)duration{
    [UIView animateWithDuration:duration animations:^{
        [self rebuildImageView];
    }];
}

This code works fine when I autorotate while image 0 is being shown, but when I’m on image 7, you can briefly see most of image 6 when rotating. This video shows what’s happening:

http://www.youtube.com/watch?v=1O3jOcTgVP8

Is there a better method I should use to reconfigure the scroll view and images when rotating the device?

Answer 1

Any frame changes put in the willAnimateRotationToInterfaceOrientation:duration method should automatically animate. So you could try removing it from the block?

Personally, I’ve had a lot more luck with this type of thing subclassing UIScrollView and putting the equivalent layout subview frame code in an override of the layoutSubviews method (don’t forget to call super or you might end up with misplaced scroll bars).