Question

For example, I have 9 grids. It order like this:

7 8 9

4 5 6

1 2 3

If I am in the position 5, the user can now scroll to 3 using one scroll. But I would like to limit they scroll to 6 only, then go to 3 or scroll to 2, and then 3. Which not allow them scroll to 3 only.

Any ideas on how to implement it?

Answer 1

Your own logic + These below three properties of UIScrollview will help you to acheive your goal.

yourScroller.directionalLockEnabled = YES;
yourScroller.pagingEnabled = YES;
[yourScroller scrollRectToVisible:yourFrame animated:YES];  

ExampleCode:

-(void)changeAndIncrementBottomScrollerPage{

    //maximum number of pages is 3
    if (3 != UpAndDownPager.currentPage) {      

        int page = UpAndDownPager.currentPage + 1;
        CGRect frame = scroller.frame;  
        frame.origin.y  = frame.size.height * page;

        if (0 != sidePager.currentPage) {

            frame.origin.x = frame.size.width * (sidePager.currentPage);
        }

        [yourScroller scrollRectToVisible:frame animated:YES];      
        UpAndDownPager.currentPage = UpAndDownPager.currentPage + 1;    

    }
}