关于Android上下文菜单改背景颜色

public boolean onContextItemSelected(MenuItem item) {
    boolean handled = false;
    boolean deleteMessage = false;
    if (item.getItemId() == R.id.delete_message) {
        deleteMessage = true;
        handled = true;
    } else if (item.getItemId() == R.id.delete_conversation) {
        deleteMessage = false;
        handled = true;
    }
    EMConversation tobeDeleteCons = adapter.getItem(((AdapterView.AdapterContextMenuInfo) item.getMenuInfo()).position);
    // 删除此会话
    EMChatManager.getInstance().deleteConversation(tobeDeleteCons.getUserName(), tobeDeleteCons.isGroup(), deleteMessage);
    InviteMessgeDao inviteMessgeDao = new InviteMessgeDao(getActivity());
    inviteMessgeDao.deleteMessage(tobeDeleteCons.getUserName());
    adapter.remove(tobeDeleteCons);
    adapter.notifyDataSetChanged();
    return handled ? true : super.onContextItemSelected(item);
}
    这是我的代码，默认是黑色的背景，我想修改成白色。请问怎么修改

 item.setTextColor(Color.WHITE);

参考：

http://zhidao.baidu.com/link?url=71786N-UInhjWI6H62hB692rx950EdTeKETRdVWD56odpcxHhevMrO7OR6itQq9uPC-qTAXo0XFEShsN633kDD2eKGfvgIOMIk3ZqmrKTmy

Item用自定义的，系统的Item你改不了