Support pushing screens to unselected tabs

android/app/src/main/java/com/reactnativenavigation/layouts/BottomTabsLayout.java

         if (sideMenuParams == null) {
             return;
         }
-
         sideMenu = new SideMenu(getContext(), sideMenuParams);
         RelativeLayout.LayoutParams lp = new LayoutParams(MATCH_PARENT, MATCH_PARENT);
         addView(sideMenu, lp);
     }
 
     private void createAndAddScreens(int position) {
-        ScreenStack newStack = new ScreenStack(activity, getContentContainer(), this);
         ScreenParams screenParams = params.tabParams.get(position);
+        ScreenStack newStack = new ScreenStack(activity, getContentContainer(), screenParams.navigatorId, this);
         newStack.pushInitialScreen(screenParams, createScreenLayoutParams(screenParams));
         screenStacks[position] = newStack;
     }
 
     @Override
     public void push(ScreenParams screenParams) {
-        getCurrentScreenStack().push(screenParams, createScreenLayoutParams(screenParams));
-        bottomTabs.setStyleFromScreen(screenParams.styleParams);
+        ScreenStack screenStack = getScreenStack(screenParams.navigatorId);
+        if (screenStack == null) {
+            return;
+        }
+
+        if (isCurrentStack(screenStack)) {
+            screenStack.push(screenParams, createScreenLayoutParams(screenParams));
+            bottomTabs.setStyleFromScreen(screenParams.styleParams);
+        } else {
+            screenStack.push(screenParams, createScreenLayoutParams(screenParams));
+        }
     }
 
     @Override
         currentScreenStack.destroy();
         removeView(currentScreenStack.peek());
 
-        ScreenStack newStack = new ScreenStack(activity, this, this);
+        ScreenStack newStack = new ScreenStack(activity, this, params.navigatorId, this);
         LayoutParams lp = createScreenLayoutParams(params);
         newStack.pushInitialScreen(params, lp);
         screenStacks[currentStackIndex] = newStack;
     }
 
     private void showStackAndUpdateStyle(ScreenStack newStack) {
-        newStack.showFirstScreen();
+        newStack.show();
         bottomTabs.setStyleFromScreen(newStack.getCurrentScreenStyleParams());
     }
 
     private void hideCurrentStack() {
         ScreenStack currentScreenStack = getCurrentScreenStack();
-        currentScreenStack.hideScreen();
+        currentScreenStack.hide();
     }
 
     private ScreenStack getCurrentScreenStack() {
         return screenStacks[currentStackIndex];
     }
 
+    private @Nullable ScreenStack getScreenStack(String navigatorId) {
+        for (ScreenStack screenStack : screenStacks) {
+            if (screenStack.getNavigatorId().equals(navigatorId)) {
+                return screenStack;
+            }
+        }
+        return null;
+    }
+
+    private boolean isCurrentStack(ScreenStack screenStack) {
+        return getCurrentScreenStack() == screenStack;
+    }
+
     private void setBottomTabsStyleFromCurrentScreen() {
         bottomTabs.setStyleFromScreen(getCurrentScreenStack().getCurrentScreenStyleParams());
     }
             });
             return true;
         }
-
         return false;
     }
 

android/app/src/main/java/com/reactnativenavigation/layouts/SingleScreenLayout.java

         if (stack != null) {
             stack.destroy();
         }
-        stack = new ScreenStack(activity, parent, this);
+        stack = new ScreenStack(activity, parent, screenParams.navigatorId, this);
         LayoutParams lp = new LayoutParams(MATCH_PARENT, MATCH_PARENT);
         stack.pushInitialScreen(screenParams, lp);
-        stack.showFirstScreen();
+        stack.show();
     }
 
     @Override

android/app/src/main/java/com/reactnativenavigation/params/ScreenParams.java

 
     public String screenInstanceId;
     public String navigatorEventId;
+    public String navigatorId;
     public Bundle navigationParams;
 
     public boolean hasTopTabs() {

android/app/src/main/java/com/reactnativenavigation/params/parsers/ScreenParamsParser.java

     private static final String KEY_SCREEN_ID = "screenId";
     private static final String KEY_SCREEN_INSTANCE_ID = "screenInstanceID";
     private static final String KEY_NAVIGATOR_EVENT_ID = "navigatorEventID";
+    private static final String KEY_NAVIGATOR_ID = "navigatorID";
     private static final String KEY_NAVIGATION_PARAMS = "navigationParams";
     private static final String KEY_RIGHT_BUTTONS = "rightButtons";
     private static final String KEY_LEFT_BUTTON = "leftButton";
         assertKeyExists(params, KEY_NAVIGATION_PARAMS);
         result.navigationParams = params.getBundle(KEY_NAVIGATION_PARAMS);
         result.navigatorEventId = result.navigationParams.getString(KEY_NAVIGATOR_EVENT_ID);
+        result.navigatorId = result.navigationParams.getString(KEY_NAVIGATOR_ID);
         result.screenInstanceId = result.navigationParams.getString(KEY_SCREEN_INSTANCE_ID);
 
         result.styleParams = new StyleParamsParser(params.getBundle(STYLE_PARAMS)).parse();

android/app/src/main/java/com/reactnativenavigation/screens/ScreenStack.java

     private LeftButtonOnClickListener leftButtonOnClickListener;
     private Stack<Screen> stack = new Stack<>();
     private final KeyboardVisibilityDetector keyboardVisibilityDetector;
+    private boolean isStackVisible = false;
+    private final String navigatorId;
+
+    public String getNavigatorId() {
+        return navigatorId;
+    }
 
     public ScreenStack(AppCompatActivity activity,
                        RelativeLayout parent,
+                       String navigatorId,
                        LeftButtonOnClickListener leftButtonOnClickListener) {
         this.activity = activity;
         this.parent = parent;
+        this.navigatorId = navigatorId;
         this.leftButtonOnClickListener = leftButtonOnClickListener;
         keyboardVisibilityDetector = new KeyboardVisibilityDetector(parent);
     }
     public void push(final ScreenParams params, RelativeLayout.LayoutParams layoutParams) {
         Screen nextScreen = ScreenFactory.create(activity, params, leftButtonOnClickListener);
         final Screen previousScreen = stack.peek();
+        if (isStackVisible) {
+            pushScreenToVisibleStack(params, layoutParams, nextScreen, previousScreen);
+        } else {
+            pushScreenToInvisibleStack(layoutParams, nextScreen, previousScreen);
+        }
+    }
+
+    private void pushScreenToVisibleStack(ScreenParams params, RelativeLayout.LayoutParams layoutParams,
+                                          Screen nextScreen, final Screen previousScreen) {
         addScreen(nextScreen, layoutParams);
         nextScreen.show(params.animateScreenTransitions, new Runnable() {
             @Override
         });
     }
 
+    private void pushScreenToInvisibleStack(RelativeLayout.LayoutParams layoutParams, Screen nextScreen,
+                                            Screen previousScreen) {
+        nextScreen.setVisibility(View.INVISIBLE);
+        addScreen(nextScreen, layoutParams);
+        removePreviousWithoutUnmount(previousScreen);
+    }
+
     private void addScreen(Screen screen, RelativeLayout.LayoutParams layoutParams) {
         parent.addView(screen, layoutParams);
         stack.push(screen);
     }
 
     private void readdPrevious(Screen previous) {
+        previous.setVisibility(View.VISIBLE);
         parent.addView(previous, 0);
         previous.preventMountAfterReattachedToWindow();
     }
         }
     }
 
-    public void showFirstScreen() {
+    public void show() {
+        isStackVisible = true;
         stack.peek().setVisibility(View.VISIBLE);
     }
 
-    public void hideScreen() {
+    public void hide() {
+        isStackVisible = false;
         stack.peek().setVisibility(View.INVISIBLE);
     }
 }