code: public void setViewEnabled(boolean enable) {
          final NotificationRootView root = mWindow.mRoot;
          root.setViewEnabled(enable);
          if (enable && mView == null) {
              mView = root.getView();
              mView.initialize(this);
              mView.addStateListener(new ViewStateListener());
          }
      }
docs: Enable/disable notification view.
  
  @param enable