how to handle touch event like UITableView or ScollView - iphone

Question

I made a customer control, inherit from UIView and add a lot of UIButtons on the UIView.
When a user touches and moves I will do some animation: let buttons move by the function touchesMoved:
- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
but buttonClick event seems to have a higher priority.
I want to it can like UITableView, scroll things have higher priority then button click.

Answer 1

You need to look into UIPanGestureRecognizer.
It allows you the ability to cancel events sent to other handlers.
Updated with additional information about how to safe previous points.
In the action callback, you gett notified of the initial touch location recognizer.state == UIGestureRecognizerStateBegan. You can save this point as an instance variable. You also get callbacks at various intervals recognizer.state == UIGestureRecognizerStateChanged. You can save this information also. Then when you get the callback with recognizer.state == UIGestureRecognizerStateEnded, you reset any instance variables.
- (void)handler:(UIPanGestureRecognizer *)recognizer
{
CGPoint location = [recognizer locationInView:self];
switch (recognizer.state)
{
case UIGestureRecognizerStateBegan:
self.initialLocation = location;
self.lastLocation = location;
break;
case UIGestureRecognizerStateChanged:
// Whatever work you need to do.
// location is the current point.
// self.lastLocation is the location from the previous call.
// self.initialLocation is the location when the touch began.
// NOTE: The last thing to do is set last location for the next time we're called.
self.lastLocation = location;
break;
}
}
Hope that helps.