Question

I’m using a few UIGestureRecognizers to pan, rotate and scale a view, which resides inside a scroll view.

My problem is that sometimes the scroll view eats the touches before the gesture recognizers do, so when this happens I end up zooming the scroll view instead of dragging the view. (It doesn’t happen all the time. I still can’t describe how to reproduce this behavior).

I’m pretty sure this can be solved in some way. For example MPMoviePlayerController doesn’t have this problem: in fact, you can put it in a scroll view, and when you pinch it, it works just fine (i.e. it doesn’t zoom the outer scroll view too). Does anyone know how does MPMoviePlayerController achieve this?

I’ve already searched for answers on SO, with no results. Thanks!

Answer 1

Disclaimer: This is just an idea, I haven’t tested this.

UIGestureRecognizerDelegate defines gestureRecognizer:shouldRecognizeSimultaneouslyWithGestureRecognizer:. You could try implementing this on your gesture recognizer delegate. This won’t prevent the scroll view from zooming. To prevent zooming you could try temporary setting maximumZoomScale minimumZoomScale to zoomScale in the recognizer action method.