Keep scene after Activity restart

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

@@ -33,14 +33,13 @@ import android.widget.FrameLayout;
 import com.hippo.util.AssertUtils;
 import com.hippo.util.ViewUtils;
 
-import java.util.Map;
-
 /**
  * {@link com.hippo.scene.Scene} is a {@code Activity} of {@link android.app.Activity}.
  * <p>
  * When start a new {@code Scene}, previous {@code Scene} can stay at screen for
  * a while. Or retain for a while before destroy.
  */
+// TODO Improve state
 public abstract class Scene {
 
     public static final int LAUNCH_MODE_STANDARD = 0;
@@ -168,8 +167,8 @@ public abstract class Scene {
     }
 
     // TODO Tell destory is it need close
-    void destroy(boolean willSave) {
-        onDestroy(willSave);
+    void destroy() {
+        onDestroy();
 
         SceneApplication.getRefWatcher(getStageActivity()).watch(this);
     }
@@ -190,12 +189,8 @@ public abstract class Scene {
         onResume();
     }
 
-    void save(Map<String, Object> transferStop) {
-        onSave(transferStop);
-    }
-
-    void restore(Map<String, Object> transferStop) {
-        onRestore(transferStop);
+    void rebirth(@Nullable Bundle savedInstanceState) {
+        onRebirth(savedInstanceState);
     }
 
     void setFitPaddingBottom(int b) {
@@ -249,10 +244,12 @@ public abstract class Scene {
     }
 
     @SuppressWarnings("ConstantConditions")
-    protected void onDestroy(boolean willSave) {
+    protected void onDestroy() {
         // Make sure soft key broad is hidden
-        InputMethodManager imm = (InputMethodManager) getStageActivity().getSystemService(Context.INPUT_METHOD_SERVICE);
-        imm.hideSoftInputFromWindow(mSceneView.getWindowToken(), 0);
+        if (mSceneView != null) {
+            InputMethodManager imm = (InputMethodManager) getStageActivity().getSystemService(Context.INPUT_METHOD_SERVICE);
+            imm.hideSoftInputFromWindow(mSceneView.getWindowToken(), 0);
+        }
     }
 
     protected void onOpen() {
@@ -269,18 +266,9 @@ public abstract class Scene {
         getSceneView().setEnableTouch(true);
     }
 
-    protected void onSave(Map<String, Object> transferStop) {
-        transferStop.put("scene_id", mId);
-        transferStop.put("scene_announcer", mAnnouncer);
-        transferStop.put("scene_curtain", mCurtain);
-    }
-
-    protected void onRestore(Map<String, Object> transferStop) {
-        mId = (Integer) transferStop.get("scene_id");
-        mAnnouncer = (Announcer) transferStop.get("scene_announcer");
-        mCurtain = (Curtain) transferStop.get("scene_curtain");
+    protected void onRebirth(@Nullable Bundle savedInstanceState) {
         if (mCurtain != null) {
-            mCurtain.onReplace();
+            mCurtain.onRebirth();
         }
     }