ios: how to get index of current ?UIscrollView page

Question

I want to know index of current scrolled page in UIScrollView. I have searched through many sites by none helps. Any suggestions are welcome.

similar question it's work for me [link] http://stackoverflow.com/questions/4132993/getting-the-current-page — sash, Jul 21 '15 at 06:28
note that the answer here may be as simple as using views.index#of ! **let index = v.superview?.subviews.index(of: v)** works perfectly in a UIScrollView — Fattie, Apr 20 '17 at 14:21
the only wholly correct answer https://stackoverflow.com/a/76058339/294884 — Fattie, Apr 19 '23 at 19:57

score 6 · Answer 1 · edited Dec 18 '15 at 17:25

6

Try this

    //Horizontal
    NSInteger pagenumber = scrollView.contentOffset.x / scrollView.bounds.size.width;
    //Vertical
    NSInteger pagenumber = scrollView.contentOffset.y / scrollView.bounds.size.height;

edited Dec 18 '15 at 17:25

Kyle Howells

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answered Oct 05 '12 at 13:58

Lithu T.V

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1

isn't it the strict opposite ? – Ben May 26 '15 at 13:58
Yes..I think the comments is opposite.will change it nw – Lithu T.V May 26 '15 at 14:23
wrong, unfortunately. You have to correctly round and encapsulate, or it will (a) often be wrong (b) often crash – Fattie Apr 19 '23 at 19:54
also, you can bounds.width https://stackoverflow.com/a/76058339/294884 – Fattie Apr 19 '23 at 19:58

score 5 · Answer 2 · answered Aug 04 '16 at 23:29

5

For those needing code (swift) , the UIScrollViewDelegate provides the method, this uses the horizontal example from above

func scrollViewDidEndDecelerating(scrollView: UIScrollView) {
    print("END Scrolling \(scrollView.contentOffset.x / scrollView.bounds.size.width)")
    index = Int(scrollView.contentOffset.x / scrollView.bounds.size.width)
}

answered Aug 04 '16 at 23:29

Mindeater

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wrong, unfortunately. You have to correctly round and encapsulate, or it will (a) often be wrong (b) often crash – Fattie Apr 19 '23 at 19:54

score 0 · Answer 3 · answered Oct 05 '12 at 10:50

0

Use the contentOffset property, which returns a CGSize that is the offset of the content in the UIScrollView.

answered Oct 05 '12 at 10:50

craigmj

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Divide it by the scrollView's `bounds.size`, you'll have the "page number". – Cyrille Oct 05 '12 at 10:53

score -1 · Answer 4 · answered Oct 05 '12 at 11:00

with the help of some mathematical calculation you can get index number of page I am sending code for reference only . I have done.

-(void)KinarafindingSelectedCategory:(UIScrollView*)scrollView{
    for (UIView *v in scrollView.subviews)
    {
        if ([v isKindOfClass:[UIButton class]])
        {
            UIButton *btn=(UIButton*)v;

            float x1=scrollView.contentOffset.x+(([UIScreen mainScreen].bounds.size.width/2)-(btn.frame.size.width/2));
            float x2=scrollView.contentOffset.x+(([UIScreen mainScreen].bounds.size.width/2)+(btn.frame.size.width/2));
            float BtnMidPoint=btn.frame.origin.x+(btn.frame.size.width/2);
            if(BtnMidPoint >= x1 && BtnMidPoint <= x2)
            {
                if(scrollView==KinaraCategory)
                {
                    KinaraSelectedCategoryName=btn.titleLabel.text;
                    KinaraSelectedCategoryID=btn.tag;
                    NSLog(@"Selected Category Tag : %d",KinaraSelectedCategoryID);
                    NSLog(@"Selected Category Name : %@",KinaraSelectedCategoryName);
                }
                else if(scrollView==KinaraSubCategory)
                {
                    KinaraSelectedSubCategoryID=btn.tag;
                    KinaraSelectedSubCategoryName=btn.titleLabel.text;

                    NSLog(@"Selected SubCategory Tag : %d",KinaraSelectedSubCategoryID);
                    NSLog(@"Selected SubCategory Name : %@",KinaraSelectedSubCategoryName);
                }
                break;
            }
        }
    }

}

ios: how to get index of current ?UIscrollView page

4 Answers4