Merge branch 'master' of https://github.com/wix/react-native-navigation

android/app/src/main/java/com/reactnativenavigation/controllers/NavigationActivity.java

         }
         if (layout != null) {
             layout.destroy();
+            layout = null;
         }
     }
 
 
     @Override
     public void onBackPressed() {
-        if (!layout.onBackPressed()) {
+        if (layout != null && !layout.onBackPressed()) {
             NavigationApplication.instance.getReactGateway().onBackPressed();
         }
     }