Update

app/src/main/java/com/hippo/scene/Scene.java

@@ -40,6 +40,9 @@ import com.hippo.util.ViewUtils;
  */
 public abstract class Scene {
 
+    public static final int LAUNCH_MODE_STANDARD = 0;
+    public static final int LAUNCH_MODE_SINGLE_TOP = 1;
+
     static final int SCENE_STATE_CREATE = 0;
     static final int SCENE_STATE_RUN = 1;
     static final int SCENE_STATE_DESTROY = 2;
@@ -86,7 +89,7 @@ public abstract class Scene {
         return mCurtain;
     }
 
-    @Nullable Announcer getAnnouncer() {
+    public @Nullable Announcer getAnnouncer() {
         return mAnnouncer;
     }
 
@@ -97,6 +100,10 @@ public abstract class Scene {
         return stageActivity;
     }
 
+    public int getLaunchMode() {
+        return LAUNCH_MODE_STANDARD;
+    }
+
     /**
      * You will get null before onCreate and after onDestroy mostly
      *
@@ -257,6 +264,9 @@ public abstract class Scene {
         mCurtain = oldScene.mCurtain;
     }
 
+    protected void onNewAnnouncer(Announcer announcer) {
+    }
+
     /**
      * It will be called if nav bar is transparent.
      * @param b the nav bar's height