code: public static void typeface(Activity activity) {
  		if (sDefaultTypefaceCollection == null) {
  			throw new IllegalStateException("Default typeface collection not initialized. Forgot to call init()?");
  		}
  		typeface(activity.findViewById(android.R.id.content), sDefaultTypefaceCollection);
  	}
docs: Apply typefaces to main acitivty view (android.R.id.content).
  @throws IllegalStateException {@link #init(TypefaceCollection)} has not been called
  @param activity to typeface custom typefaces to