message: Created currentActivity variable
diff: package com.navigation.reactnative;
  +import android.app.Activity;
  import android.content.Intent;
  import android.view.View;
  import android.view.ViewGroup;
  @@ -33,20 +34,21 @@ public class NavigationStackView extends ViewGroup {
  @Override
  public void addView(View child, int index) {
  Intent intent;
  + Activity currentActivity = ((ThemedReactContext) getContext()).getCurrentActivity();
  if (index == 0) {
  if (scenes.size() > 0) {
  intent = scenes.get(0).intent;
  - ((ThemedReactContext) getContext()).getCurrentActivity().navigateUpTo(intent);
  + currentActivity.navigateUpTo(intent);
  scenes.clear();
  }
  super.addView(child, index);
  - intent = ((ThemedReactContext) getContext()).getCurrentActivity().getIntent();
  + intent = currentActivity.getIntent();
  }
  else {
  Class scene = index % 2 == 1 ? SceneActivity.class : AlternateSceneActivity.class;
  intent = new Intent(getContext(), scene);
  intent.putExtra(SceneActivity.CRUMB, index);
  - ((ThemedReactContext) getContext()).getCurrentActivity().startActivity(intent, null);
  + currentActivity.startActivity(intent, null);
  }
  scenes.add(index, new SceneItem(index, intent, child));
  }
  