iOS: Can I override pinch in/out behavior of UIScrollView?

Question

I\'m drawing a graph on a UIView, which is contained by a UIScrollView so that the user can scroll horizontally to look around the entire graph.

Answer 1

You should be able to subclass UIScrollView and override the touchesBegan: method. Don't call [super touchesBegan:] but instead, adjust the zoom as you like:

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
    //Anything you want. Probably you would want to store all the touches
    //or their values, so that you can compare them to the touches
    //in the touchesEnded: method, 
    //thus letting you know what the pinch amount was
}

If you like, you can judge whether it's a pinch or not, and if it's not, call the super method, and only handle it yourself for custom pinches.