title: Fragment slide up animation doesn't show fragment underneath
body: <p>When opening a fragment I need to add an animation to slide it up from the bottom and then when that fragment closes it needs to slide back down off the screen.</p>
  
  <p>I have the following code in the fragment that slides up, which is almost working:</p>
  
  <pre><code>public override Animator OnCreateAnimator (FragmentTransit transit, bool enter, int nextAnim) {
          var display = this.Activity.WindowManager.DefaultDisplay;
          var size = new Point ();
          display.GetSize (size);
          var displayHeight = size.Y;
  
          var animator = enter ? 
              ObjectAnimator.OfFloat (this, "translationY", displayHeight, 0) : 
              ObjectAnimator.OfFloat (this, "translationY", 0, displayHeight);
          animator.SetDuration (300);
          return animator;
      }
  </code></pre>
  
  <p>There is one issue around the slide up animation... It immediately shows the fragment's white background and action bar (it doesn't animate), the content below the action bar does slide up. This means that you lose the effect of showing the previous fragment underneath the new fragment as it slides up, as you just see the white background behind the content sliding up.</p>
  
  <p>Sliding back down works correctly, the fragment over top slides back down and you can see the fragment beneath it as it slides down.</p>
  
  <p>Here is the code that opens the new fragment, in case it's relevant:</p>
  
  <pre><code>var transaction = activity.FragmentManager.BeginTransaction ();
  transaction.Replace (navigationContext.ContainerResourceId, fragment, fragment.Name);
  transaction.AddToBackStack (fragment.Name);
  transaction.Commit ();
  </code></pre>
  
  <p>Any ideas as to how I can make the slide up animation work correctly, showing the fragment underneath as it slides up?</p>