Register for audio progress events.

Closes #4288
// FREEBIE

src/org/thoughtcrime/securesms/components/AudioView.java

@@ -29,6 +29,8 @@ import org.thoughtcrime.securesms.util.Util;
 import java.io.IOException;
 import java.util.concurrent.TimeUnit;
 
+import de.greenrobot.event.EventBus;
+
 public class AudioView extends FrameLayout implements AudioSlidePlayer.Listener {
 
   private static final String TAG = AudioView.class.getSimpleName();
@@ -76,6 +78,18 @@ public class AudioView extends FrameLayout implements AudioSlidePlayer.Listener
     }
   }
 
+  @Override
+  protected void onAttachedToWindow() {
+    super.onAttachedToWindow();
+    if (!EventBus.getDefault().isRegistered(this)) EventBus.getDefault().registerSticky(this);
+  }
+
+  @Override
+  protected void onDetachedFromWindow() {
+    super.onDetachedFromWindow();
+    EventBus.getDefault().unregister(this);
+  }
+
   public void setAudio(final @NonNull MasterSecret masterSecret,
                        final @NonNull AudioSlide audio,
                        final boolean showControls)