Question

Well I have an image and I I want that when I touch it and then I move my finger it follows it.but I want that it follows it only vertically like a vertical scrollview(but I don’t wanna use a scrollview).How can I do this please. sorry for my english I’m french :/

Answer 1

Why wouldn’t you subclass UIScrollView for your view that displays the image? If you do it’s pretty simple: define its size so that the horizontal length doesn’t exceed the screen length. You’d have to also remember to change this if you allow rotation of the device/view to landscape. Suppose the width of your UIScrollView is 320, you would do this:

CGSize scrollableSize = CGSizeMake(320, myScrollableHeight);
[myScrollView setContentSize:scrollableSize];

Where myScrollableHeight is the full height of the image.

I’ve never used it but if that doesn’t work there is apparently a method you can provide for your UIScrollView class that is called whenever the user attempts to scroll and you can just not adjust the X-coordinate there:

float oldX; // make this ivar in your .h file

- (void)scrollViewDidScroll:(UIScrollView *)aScrollView
{
    [aScrollView setContentOffset: CGPointMake(aScrollView.contentOffset.y, oldX)];
}