Hide and show video players as content changes.

app/src/main/java/org/thoughtcrime/securesms/giph/mp4/GiphyMp4ProjectionPlayerHolder.java

@@ -2,6 +2,7 @@ package org.thoughtcrime.securesms.giph.mp4;
 
 import android.content.Context;
 import android.view.LayoutInflater;
+import android.view.View;
 import android.view.ViewGroup;
 import android.widget.FrameLayout;
 
@@ -63,6 +64,14 @@ public final class GiphyMp4ProjectionPlayerHolder implements Player.EventListene
     this.onPlaybackReady = onPlaybackReady;
   }
 
+  public void hide() {
+    container.setVisibility(View.GONE);
+  }
+
+  public void show() {
+    container.setVisibility(View.VISIBLE);
+  }
+
   @Override
   public void onPlayerStateChanged(boolean playWhenReady, int playbackState) {
     if (playbackState == Player.STATE_READY) {

app/src/main/java/org/thoughtcrime/securesms/giph/mp4/GiphyMp4ProjectionRecycler.java

@@ -77,6 +77,10 @@ public final class GiphyMp4ProjectionRecycler implements GiphyMp4PlaybackControl
     for (final Integer key : markedForDeletion) {
       playing.remove(key);
     }
+
+    for (int i = 0; i < notPlaying.size(); i++) {
+      notPlaying.valueAt(i).hide();
+    }
   }
 
   private void updateDisplay(@NonNull RecyclerView recyclerView, @NonNull GiphyMp4ProjectionPlayerHolder holder, @NonNull GiphyMp4Playable giphyMp4Playable) {
@@ -100,6 +104,7 @@ public final class GiphyMp4ProjectionRecycler implements GiphyMp4PlaybackControl
       holder.setOnPlaybackReady(null);
       giphyMp4Playable.showProjectionArea();
 
+      holder.show();
       holder.setOnPlaybackReady(giphyMp4Playable::hideProjectionArea);
       holder.playContent(giphyMp4Playable.getMediaSource(), giphyMp4Playable.getPlaybackPolicyEnforcer());
     }

app/src/main/res/layout/giphy_mp4_fragment.xml

@@ -24,6 +24,7 @@
         style="@style/Signal.Text.Body"
         android:layout_width="match_parent"
         android:layout_height="match_parent"
+        android:background="?android:windowBackground"
         android:gravity="center"
         android:text="@string/giphy_fragment__nothing_found"
         android:visibility="gone" />