How can I set the width of the ScrollView content?

Question

Im working on a scrollview and I want it to be with paging enabled, but when I try to set a custom width to the content I cant, I need someones help, Thanks!

Heres what Im trying:

- (void)scrollViewWillEndDragging:(UIScrollView *)scrollView withVelocity:(CGPoint)velocity targetContentOffset:(inout CGPoint *)targetContentOffset {

    int PageNum = (int)(scrollView.contentOffset.x / 140);
    targetContentOffset->x = PageNum * (int)(targetContentOffset->x / PageNum);

}

When scrollViewDidScroll: I add a NSlog and Its printing correctly the current page, what does not work is the custom for the paging width:

- (void)scrollViewDidScroll:(UIScrollView *)scrollView{

    int PageNum = (int)(scrollView.contentOffset.x / 140);
    NSLog(@"%d", PageNum);

}

Hope someone can Help me, thanks!

score 0 · Answer 1 · answered Mar 29 '14 at 23:55

0

Frankly I do not really understand your code and what you are up to. This answer may not even be related to your problem, but it may help anyway.

targetContentOffset->x = PageNum * (int)(targetContentOffset->x / PageNum);

is quite an equivalent to

targetContentOffset->x = (int)(targetContentOffset->x);

which does not seem to do much but some rounding. If you do this for the side-effects of the rounding then ignore my answer.

answered Mar 29 '14 at 23:55

Hermann Klecker

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I divided scrollView.contentOffset.x into 140 because thats the width I want (if thats what you dont understand), I tried what you are telling me and its the same :S, thanks – Karlo A. López Mar 30 '14 at 00:02
Of course it is the same. You are doing x=x. What do you expect from that assignment? Again, I am not sure whether this is related to your problem. In the best case it is just a waiste of cpu usage. – Hermann Klecker Mar 30 '14 at 00:04

score 0 · Accepted Answer · answered Mar 30 '14 at 01:39

You do not have to implement scrollViewWillEndDragging:withVelocity:targetContentOffset: method to enable paging in a UIScrollView. To do this, you need only:

Set pagingEnabled property of your scrollview to YES. Documentation says about this property: If the value of this property is YES, the scroll view stops on multiples of the scroll view’s bounds when the user scrolls.
Add your subviews (pages) to the scrollview. Their widths must be equal to the scrollview's width, to retrieve a horizontal-paged scrollview.
Set your scrollview's contentSize property.

So your code should be something like this:

[scrollView setPagingEnabled:YES];
NSInteger numberOfPages = 100;

CGFloat pageWidth = scrollView.bounds.size.width;
CGFloat pageHeight = scrollView.bounds.size.height; // can be something else

for(NSInteger i = 0; i < numberOfPages; i++)
{
    UIView * view = [[UIView alloc] initWithFrame:CGRectMake(i * pageWidth, 0, pageWidth, pageHeight)];
    // do somethings with the page view
    [scrollView addSubview:view];
}

[scrollView setContentSize:CGSizeMake(numberOfPages * pageWidth, scrollView.bounds.size.height)];

How can I set the width of the ScrollView content?

2 Answers2