Rotate view using CGAfffineTransformRotate

Question

I have a circular image which i am trying to rotate so that the yellow and black striped circle stays under the users finger and rotates in both directions. I have this so far:

- (void)handleJogShuttle:(UIPanGestureRecognizer *)recognizer {

    UIView *shuttle = [recognizer view];

    if ([recognizer state] == UIGestureRecognizerStateBegan || [recognizer state] == UIGestureRecognizerStateChanged) {

        [recognizer view].transform = CGAffineTransformRotate([[recognizer view] transform],M_PI / 20.0f);
        [recognizer setTranslation:CGPointZero inView:[shuttle superview]];

    }   

}

Also, currently, the slightest movement can cause the view to rotate in a full circle, which is obviously not desired.

Thanks.

Answer 1

I suspect this method gets called A LOT. Try using NSLog and check how many time it does. Anyway, you are not calculating the angle properly, you could try using - (CGPoint)translationInView:(UIView *)view from the recognizer to calculate the correct angle to rotate.