title: Move a UIImageView with an animation
body: <p>I have implemented a slider bar type UI control, like the Unlock mechanism on the iPhone.</p>
  
  <p>When the touchesEnded method gets called, I return the slider to it's starting position. Instead, I would like to animate its move back to it's starting position.</p>
  
  <p>The code should be something like this, but it doesn't work. What am I doing wrong here?</p>
  
  <p>Self.unlock is a UIImageView:</p>
  
  <pre><code>CABasicAnimation *theAnimation;
  theAnimation = [CABasicAnimation animationWithKeyPath:@"position.x"];
  theAnimation.fromValue = [NSNumber numberWithFloat:BEGINX];
  theAnimation.toValue = [NSNumber numberWithFloat: 0.0];
  theAnimation.duration = 0.5;
  [self.unlock addAnimation: theAnimation];
  </code></pre>
  
  <p>Sorry for the bone-headed question!</p>