Send visibility events for TopTabs screens

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

     @Override
     public void onPageSelected(int position) {
         EventBus.instance.post(new ViewPagerScreenChangedEvent());
+        sendDisappearEvents(currentPosition);
         currentPosition = position;
         EventBus.instance.post(new ScreenChangedEvent(pageParams.get(currentPosition)));
         sendTabSelectedEventToJs();
+        sendAppearEvents(position);
     }
 
+
     @Override
     public void onPageScrollStateChanged(int state) {
         if (state == ViewPager.SCROLL_STATE_DRAGGING) {
         }
     }
 
+    private void sendAppearEvents(int position) {
+        PageParams pageParams = this.pageParams.get(position);
+        pageParams.timestamp = System.currentTimeMillis();
+        NavigationApplication.instance.getEventEmitter().sendWillAppearEvent(pageParams, NavigationType.TopTabSelected);
+        NavigationApplication.instance.getEventEmitter().sendDidAppearEvent(pageParams, NavigationType.TopTabSelected);
+    }
+
+    private void sendDisappearEvents(int position) {
+        PageParams pageParams = this.pageParams.get(position);
+        pageParams.timestamp = System.currentTimeMillis();
+        NavigationApplication.instance.getEventEmitter().sendWillDisappearEvent(pageParams, NavigationType.TopTabSelected);
+        NavigationApplication.instance.getEventEmitter().sendDidDisappearEvent(pageParams, NavigationType.TopTabSelected);
+    }
+
     private void sendTabSelectedEventToJs() {
         WritableMap data = Arguments.createMap();
         String navigatorEventId = contentViews.get(currentPosition).getNavigatorEventId();

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

     Push,
     Pop,
     BottomTabSelected,
+    TopTabSelected,
     InitialScreen,
     ShowModal,
     DismissModal,

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

     public abstract void setOnDisplayListener(OnDisplayListener onContentViewDisplayedListener);
 
     public void show(NavigationType type) {
-        NavigationApplication.instance.getEventEmitter().sendWillAppearEvent(screenParams, type);
-        NavigationApplication.instance.getEventEmitter().sendDidAppearEvent(screenParams, type);
+        NavigationApplication.instance.getEventEmitter().sendWillAppearEvent(getScreenParams(), type);
+        NavigationApplication.instance.getEventEmitter().sendDidAppearEvent(getScreenParams(), type);
         screenAnimator.show(screenParams.animateScreenTransitions);
     }
 
     public void show(boolean animated, final NavigationType type) {
-        NavigationApplication.instance.getEventEmitter().sendWillAppearEvent(screenParams, type);
+        NavigationApplication.instance.getEventEmitter().sendWillAppearEvent(getScreenParams(), type);
         screenAnimator.show(animated, new Runnable() {
             @Override
             public void run() {
-                NavigationApplication.instance.getEventEmitter().sendDidAppearEvent(screenParams, type);
+                NavigationApplication.instance.getEventEmitter().sendDidAppearEvent(getScreenParams(), type);
             }
         });
     }
 
     public void show(boolean animated, final Runnable onAnimationEnd, final NavigationType type) {
-        NavigationApplication.instance.getEventEmitter().sendWillAppearEvent(screenParams, type);
+        NavigationApplication.instance.getEventEmitter().sendWillAppearEvent(getScreenParams(), type);
         setStyle();
         screenAnimator.show(animated, new Runnable() {
             @Override
             public void run() {
-                NavigationApplication.instance.getEventEmitter().sendDidAppearEvent(screenParams, type);
+                NavigationApplication.instance.getEventEmitter().sendDidAppearEvent(getScreenParams(), type);
                 if (onAnimationEnd != null) onAnimationEnd.run();
             }
         });
     }
 
     private void hide(boolean animated, final Runnable onAnimatedEnd, final NavigationType type) {
-        NavigationApplication.instance.getEventEmitter().sendWillDisappearEvent(screenParams, type);
+        NavigationApplication.instance.getEventEmitter().sendWillDisappearEvent(getScreenParams(), type);
         screenAnimator.hide(animated, new Runnable() {
             @Override
             public void run() {
-                NavigationApplication.instance.getEventEmitter().sendDidDisappearEvent(screenParams, type);
+                NavigationApplication.instance.getEventEmitter().sendDidDisappearEvent(getScreenParams(), type);
                 if (onAnimatedEnd != null) onAnimatedEnd.run();
             }
         });

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

         isStackVisible = true;
         stack.peek().setStyle();
         stack.peek().setVisibility(View.VISIBLE);
-        stack.peek().screenParams.timestamp = System.currentTimeMillis();
-        NavigationApplication.instance.getEventEmitter().sendWillAppearEvent(stack.peek().screenParams, type);
-        NavigationApplication.instance.getEventEmitter().sendDidAppearEvent(stack.peek().screenParams, type);
+        stack.peek().getScreenParams().timestamp = System.currentTimeMillis();
+        NavigationApplication.instance.getEventEmitter().sendWillAppearEvent(stack.peek().getScreenParams(), type);
+        NavigationApplication.instance.getEventEmitter().sendDidAppearEvent(stack.peek().getScreenParams(), type);
     }
 
     public void hide(NavigationType type) {
-        NavigationApplication.instance.getEventEmitter().sendWillDisappearEvent(stack.peek().screenParams, type);
-        NavigationApplication.instance.getEventEmitter().sendDidDisappearEvent(stack.peek().screenParams, type);
+        NavigationApplication.instance.getEventEmitter().sendWillDisappearEvent(stack.peek().getScreenParams(), type);
+        NavigationApplication.instance.getEventEmitter().sendDidDisappearEvent(stack.peek().getScreenParams(), type);
         isStackVisible = false;
         stack.peek().setVisibility(View.INVISIBLE);
     }