code: protected void setFirstView() {
          final AbstractLmlView firstView = getCurrentView();
          if (firstView == null) {
              throw new GdxRuntimeException("No view marked as first. Unable to start application.");
          }
          setCurrentView(null);
          initiateView(firstView);
          setView(firstView, null);
      }
docs: It is assumed that the first view was set using {@link #forceCurrentView(View)} method during context
  initiation. This method ensures smooth showing of the first view.
  
  @throws GdxRuntimeException if first view was not set.