title: How to interrupt UIView animation before completion?
body: <p>I am using [UIView animateWithDuration... ] in order to display a text for each page of my app. Each page got its own text. I'm swiping to navigate between pages. I am using a 1 second dissolve effect to have the text fading in after the page is displayed.</p>
  
  <p>Here's the problem: If I'm swiping during that 1 second (during which the text is fading in) the animation will complete when the next page appears and 2 texts will overlap (the previous and the current).</p>
  
  <p>The solution I'd like to implement is to interrupt the animation if I happen to swipe during its occurrence. I just cannot make it happen. [self.view.layer removeAllAnimations]; does not work for me.</p>
  
  <p>Here's my animation code:</p>
  
  <pre><code>   - (void) replaceContent: (UITextView *) theCurrentContent withContent: (UITextView *) theReplacementContent {
  
      theReplacementContent.alpha = 0.0;
      [self.view addSubview: theReplacementContent];
  
  
      theReplacementContent.alpha = 0.0;
  
      [UITextView animateWithDuration: 1.0
                                delay: 0.0
                              options: UIViewAnimationOptionTransitionCrossDissolve
                           animations: ^{
                               theCurrentContent.alpha = 0.0;
                               theReplacementContent.alpha = 1.0;
                           }
                           completion: ^(BOOL finished){
                               [theCurrentContent removeFromSuperview];
                               self.currentContent = theReplacementContent;
                               [self.view bringSubviewToFront:theReplacementContent];
                           }];
  
     }
  </code></pre>
  
  <p>Do you guys know how to make this work? Do you know any other way to address this issue?</p>