ios：如何获取当前的索引？UIscrollView页面

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.

Answer 1

Try this

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

Answer 2

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)
}

Answer 3

使用contentOffset属性，该属性返回一个CGSize ，它是UIScrollView内容的偏移量。

Answer 4

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;
            }
        }
    }

}