How to transition a gesture from a UIPinchGestureRecognizer handler to a UIPanGestureRecognizer handler?

Question

I have a handler method for a UIPinchGestureRecognizer that is used to scale a view. What I'm trying to is to make it so that while two touches are on screen for the pinch gesture, and if a finger is lifted, the remaining finger would be managed by a pan gesture recognizer. Is there any way to do this? I can't think of a proper way to pass one gesture from one handler to another.

Answer 1

This should be pretty easy. Create two gesture recognisers. the UIPinchGestureRecognizer and the UIPanGestureRecognizer. Don't forget to become the delegate of both!

    pinchRecognizer = [[UIPinchGestureRecognizer alloc] initWithTarget:self action:@selector(scaleHandler:)];
    [pinchRecognizer setDelegate:self];
    [pinchRecognizer setDelaysTouchesBegan:NO];
    [pinchRecognizer setDelaysTouchesEnded:NO];
    [pinchRecognizer setCancelsTouchesInView:NO];
    panRecognizer = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(panHandler:)];
    [panRecognizer setMaximumNumberOfTouches:2];
    [panRecognizer setMinimumNumberOfTouches:1];
    [panRecognizer setDelegate:self];
    [panRecognizer setDelaysTouchesBegan:NO];
    [panRecognizer setDelaysTouchesEnded:NO];
    [panRecognizer setCancelsTouchesInView:NO];

Now implement the following method of the gesture delegate.

- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer{
return YES;

}

This will make both handlers be triggered, so that when you release one of the fingers it will pan, but when you have both of them it will pinch.