Question

Please could you tell me how to rotate a UIView (with a pie chart on) as if its on a pivot. It will only rotate once the user has flicked the view.

Answer 1

You’d use something like this:

- (void)spin
{
        CABasicAnimation *fullRotation;
        fullRotation = [CABasicAnimation animationWithKeyPath:@"transform.rotation"];
        fullRotation.fromValue = [NSNumber numberWithFloat:0];
        fullRotation.toValue = [NSNumber numberWithFloat:M_PI * 360 / 180.0];
        fullRotation.duration = 0.25;
        fullRotation.repeatCount = 1;
        [self.view.layer addAnimation:fullRotation forKey:@"360"];
}

Merely call the spin method when you want to spin 360º. Adjust as needed to spin more, less, faster, slower, etc.

EDIT: Should note, that in the above code, the view property is the one we’re rotating, in case it wasn’t obvious. So change self.view to whatever view you want to rotate.