Two scroll view work Simultaneous with one touch

Question

I am working on application in it I have to work with two scroll view Simultaneous in one touch. It means if I scroll one scroll view at same time another scroll view must scroll with it.

If this is possible then how can it be done?

Answer 1

Implement the UIScrollViewDelegate protocol in the view controller containing both scroll views. In the:

- (void)scrollViewDidScroll:(UIScrollView *)scrollView

delegate method, get the content offset:

CGPoint offset = [scrollViewA contentOffset]; // or scrollViewB

Then set the other control with:

- (void)setContentOffset:(CGPoint)contentOffset animated:(BOOL)animated

You can determine which one to change by comparing in the delegate method above:

if( scrollView == scrollViewA ) // change offset of B
else // change offset of A

Answer 2

Don't have to read

Generally (at least from what I know) it's bad "style" to have 2 UIScrollView/UITableVIew's in each other because it causes the UI to be hard to interact with. But I think if you have a valid enough use/reason for doing it then I'll show you a way to get it done.

CODE!

If it was me then I'd just override the UIScrollView's touchesMoved method and scroll the other UIScrollView that way.

Within scrollView_1

-(void) touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event  {

    UITouch *touch = [ touches anyObject];
    CGPoint newLocation = [touch locationInView: [touch view]];
    CGPoint oldLocation = [touch previousLocationInView:touch.view];
    CGPoint translation = CGPointMake(newLocation.x - oldLocation.x, newLocation.y - oldLocation.y);
    scrollView_2.contentOffset = CGPointMake(scrollView_2.contentOffset.x + translation.x, scrollView_2.contentOffset.y + translation.y)

}

Hope this helps