UIScrollView - Scroll, Zoom, and Touches?

Question

Im having an issue with a UIScrollView that I cannot figure out.
what I want to be able to do is to add images to a scrollview, and move them around by touching and moving them, while still being able to scroll/zoom the scrollview.
I've got an app where I have a ViewController whoes view (MyScrollView) is a custom view inherited from a UIScrollView.
MyScrollView implements touchesShouldBegin, touchesMoved and touchesEnd.
I add some subviews (UIImageViews) to MyScrollView.
when a touch event is handled, I compare the contentview to each of my UIImageView subviews, and if they match, then I save off which image is being moved. in thouchesmoved, I apply my changes to the selected subview.
I also have MyScrollViews delegate set (the viewController), and have implemented the two functions needed to zoom.
Now, here is the weird thing. If I comment out the touchesmoved implementation in MyScrollView, then MyScrollView will scroll and zoom like expected, but wont move the subviews (expected), but if I uncomment the touchesmoved implementation, then I can move my subviews, but MyScrollView no longer scrolls or zooms.
any thoughts as to why I cant get both working at the same time?

Answer 1

Since MyScrollView is a subclass of UIScrollView, you need to manually call the touchesMoved for the UIScrollView parent object so that it can do its default scrolling behavior. When you commented out your custom touchesMoved, then the message was automatically being passed to the UIScrollView's touchesMoved method.
At the end of your touchesMoved implementation, put
[super touchesMoved:touches withEvent:event];
Assuming "touches" and "event" are the names of arguments in your function.