Question

I followed the tutorial about how to create a scrollView Page Control: http://www.iosdevnotes.com/2011/03/uiscrollview-paging/

This tutorial is really good and I implement well the code. Here my question:

I want to put a space between the my PageViews, but when it change the page it show the space between the views in the next page. The scroll must stop after the space when I change the page.

I changed the tutorial code here:

- (void)viewDidLoad {
    [super viewDidLoad];

    NSArray *colors = [NSArray arrayWithObjects:[UIColor redColor], [UIColor greenColor], [UIColor blueColor], nil];

    #define space 20

    for (int i = 0; i < colors.count; i++) {
        CGRect frame;
        frame.origin.x = (self.scrollView.frame.size.width + space) * i;
        frame.origin.y = 0;
        frame.size = self.scrollView.frame.

        UIView *subview = [[UIView alloc] initWithFrame:frame];
        subview.backgroundColor = [colors objectAtIndex:i];
        [self.scrollView addSubview:subview];
        [subview release];
    }

    self.scrollView.contentSize = CGSizeMake(self.scrollView.frame.size.width * colors.count+ space*(colors.count-1), self.scrollView.frame.size.height);
}

Answer 1

It sounds like you want a “gutter” between the pages, so that each page fills the scroll view and the gutter is only visible while the user is dragging the view. The built-in Photos app does this, for example.

Make your scroll view wider by space points. For example, if you want the scroll view to appear to be as wide as the screen (320 points), with a 20 point margin between items, then make the scroll view 340 points wide, with the extra 20 points hanging off the right edge of the screen.

- (void)viewDidLoad {
    [super viewDidLoad];

    NSArray *colors = [NSArray arrayWithObjects:[UIColor redColor], [UIColor greenColor], [UIColor blueColor], nil];

    #define kGutterWidth 20

    UIScrollView *scrollView = self.scrollView;
    CGRect scrollViewFrame = scrollView.frame;
    scrollViewFrame.size.width += kGutterWidth;
    scrollView.frame = scrollViewFrame;

    CGSize scrollViewSize = scrollView.bounds.size;

    for (int i = 0; i < colors.count; i++) {
        CGRect frame = CGRectMake(scrollViewSize.width * i, 0,
            scrollViewSize.width - kGutterWidth, scrollViewSize.height);
        UIView *subview = [[UIView alloc] initWithFrame:frame];
        subview.backgroundColor = [colors objectAtIndex:i];
        [scrollView addSubview:subview];
        [subview release];
    }

    scrollView.contentSize = CGSizeMake(
        colors.count * scrollViewSize.width,
        scrollViewSize.height);
}