title: Android: Expand/collapse animation
body: <p>Let's say I have a vertical linearLayout with :</p>
  
  <pre><code>[v1]
  [v2]
  </code></pre>
  
  <p>By default v1 has visibily = GONE. I would like to show v1 with an expand animation and push down v2 at the same time.</p>
  
  <p>I tried something like this:</p>
  
  <pre><code>Animation a = new Animation()
  {
      int initialHeight;
  
      @Override
      protected void applyTransformation(float interpolatedTime, Transformation t) {
          final int newHeight = (int)(initialHeight * interpolatedTime);
          v.getLayoutParams().height = newHeight;
          v.requestLayout();
      }
  
      @Override
      public void initialize(int width, int height, int parentWidth, int parentHeight) {
          super.initialize(width, height, parentWidth, parentHeight);
          initialHeight = height;
      }
  
      @Override
      public boolean willChangeBounds() {
          return true;
      }
  };
  </code></pre>
  
  <p>But with this solution, I have a blink when the animation starts. I think it's caused by v1 displaying full size before the animation is applied.</p>
  
  <p>With javascript, this is one line of jQuery! Any simple way to do this with android?</p>