To hide other menu items from ActionBar/Toolbar when SearchView is expanded or open you need to apply OnSearchClickListener on it.
On the onCreateOptionsMenu method set OnSearchClickListener like this:-

// hide other menu item when SearchView is open or expanded
searchView.setOnSearchClickListener(new View.OnClickListener() {
  @Override
  public void onClick(View v) {
    if (menu != null) {
         menu.findItem(R.id.action_add_reminder).setVisible(false);
         menu.findItem(R.id.action_logout).setVisible(false);
      }
   }
});

Now to reopen or show again the other menu items you need to set the OnCloseListener on the SearchView

 // show other menu item when SearchView close
searchView.setOnCloseListener(new SearchView.OnCloseListener() {
   @Override
    public boolean onClose() {
    // re-show the action button
    if (menu != null) {
        menu.findItem(R.id.action_add_reminder).setVisible(true);
        menu.findItem(R.id.action_logout).setVisible(true);
      }
      return false;
    }
});