Amount of scrolling in scrollViewWillBeginDragging

Question

Is there any way to find how much UITableView has been scrolled in any direction ? I am interested in amount not in direction.

Answer 1

You can easily grab the exact offset of the table view by looking at its contentOffset property. For the vertical scroll, look at:

tableView.contentOffset.y;

and with this you can take your tableview to any particular location

[theTableView scrollToRowAtIndexPath:[NSIndexPath indexPathForRow:savedScrollPosition inSection:0] atScrollPosition:UITableViewScrollPositionTop animated:NO];                        
CGPoint point = theTableView.contentOffset;
point .y -= theTableView.rowHeight;
theTableView.contentOffset = point;

for you requirement of load more cells after 10 you can use this logic

- (void)scrollViewDidScroll:(UIScrollView *)aScrollView {
    CGPoint offset = aScrollView.contentOffset;
    CGRect bounds = aScrollView.bounds;
    CGSize size = aScrollView.contentSize;
    UIEdgeInsets inset = aScrollView.contentInset;
    float y = offset.y + bounds.size.height - inset.bottom;
    float h = size.height;
    // NSLog(@"offset: %f", offset.y);   
    // NSLog(@"content.height: %f", size.height);   
    // NSLog(@"bounds.height: %f", bounds.size.height);   
    // NSLog(@"inset.top: %f", inset.top);   
    // NSLog(@"inset.bottom: %f", inset.bottom);   
    // NSLog(@"pos: %f of %f", y, h);

    float reload_distance = 10;
    if(y > h + reload_distance) {
        NSLog(@"load more rows");
    }
}

Answer 2

You need to measure the contentOffset of the UITableView when dragging begins and when it ends. Take a difference between the two, it will give you the amount of change from initial to final position.

CGPoint oldOffset;
CGPoint newOffset;

- (void)scrollViewWillBeginDragging:(UIScrollView *)scrollView {
      oldOffset = scrollView.contentOffset;
}

- (void)scrollViewWillEndDragging:(UIScrollView *)scrollView withVelocity:(CGPoint)velocity targetContentOffset:(inout CGPoint *)targetContentOffset {
      newOffset = *targetContentOffset;
      CGPoint diff = {newOffset.x - oldOffset.x, newOffset.y - oldOffset.y};

      // Where diff.x => amount of change in x-coord of offset
      // diff.y => amount of change in y coord of offset
}

Hope that helps!

Answer 3

you can find it using below syntax...

NSLog(@"scrolled:%f",yourtableview.contentOffset.y);//y for vertical, x for horizontal