Cover ScreenImpl to RelativeLayout

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

 import android.util.Log;
 import android.view.View;
 import android.view.Window;
-import android.widget.LinearLayout;
+import android.widget.RelativeLayout;
 
 import com.reactnativenavigation.animation.OnScrollAnimator;
 import com.reactnativenavigation.params.ScreenParams;
 import static android.view.ViewGroup.LayoutParams.MATCH_PARENT;
 import static android.view.ViewGroup.LayoutParams.WRAP_CONTENT;
 
-public class ScreenImpl extends LinearLayout implements Screen, ScrollDirectionListener.OnScrollChanged {
+public class ScreenImpl extends RelativeLayout implements Screen, ScrollDirectionListener.OnScrollChanged {
 
     private final ScreenParams screenParams;
     private ContentView contentView;
     public ScreenImpl(Context context, ScreenParams screenParams) {
         super(context);
         this.screenParams = screenParams;
-        setOrientation(VERTICAL);
 
         createViews();
         setStyle(screenParams.styleParams);
 
     private void addTopBar() {
         topBar = new TopBar(getContext());
-        addView(topBar, new LinearLayout.LayoutParams(MATCH_PARENT, WRAP_CONTENT));
+        addView(topBar, new LayoutParams(MATCH_PARENT, WRAP_CONTENT));
     }
 
     private void addContentView() {
         contentView = new ContentView(getContext(), screenParams, this);
-        addView(contentView, new LayoutParams(MATCH_PARENT, MATCH_PARENT));
+        RelativeLayout.LayoutParams params = new RelativeLayout.LayoutParams(MATCH_PARENT, MATCH_PARENT);
+        params.addRule(RelativeLayout.BELOW, topBar.getId());
+        addView(contentView, params);
         contentView.init();
     }
 

android/app/src/main/java/com/reactnativenavigation/utils/ViewUtils.java

 
 import com.reactnativenavigation.NavigationApplication;
 
+import java.util.concurrent.atomic.AtomicInteger;
+
 public class ViewUtils {
+    private static final AtomicInteger viewId = new AtomicInteger();
+
     public static void runOnPreDraw(final View view, final Runnable task) {
         view.getViewTreeObserver().addOnPreDrawListener(new ViewTreeObserver.OnPreDrawListener() {
             @Override
         float scale = NavigationApplication.instance.getResources().getDisplayMetrics().density;
         return dp * scale + 0.5f;
     }
+
+    public static int generateViewId() {
+        return viewId.incrementAndGet();
+    }
 }
 

android/app/src/main/java/com/reactnativenavigation/views/TopBar.java

 import android.support.design.widget.AppBarLayout;
 
 import com.reactnativenavigation.params.TitleBarButtonParams;
+import com.reactnativenavigation.utils.ViewUtils;
 
 import java.util.List;
 
     public TopBar(Context context) {
         super(context);
         setFitsSystemWindows(true);
+        setId(ViewUtils.generateViewId());
     }
 
     public void addTitleBarAndSetButtons(List<TitleBarButtonParams> buttons, String navigatorEventId) {