code: public static void showText(Activity activity, CharSequence text, Style style, int viewGroupResId) {
      makeText(activity, text, style, (ViewGroup) activity.findViewById(viewGroupResId)).show();
    }
docs: Creates a {@link Crouton} with provided text and style for a given activity
  and displays it directly.
  
  @param activity
  The {@link Activity} that represents the context in which the Crouton should exist.
  @param text
  The text you want to display.
  @param style
  The style that this {@link Crouton} should be created with.
  @param viewGroupResId
  The resource id of the {@link ViewGroup} that this {@link Crouton} should be added to.