Java 对话框、适配器和数据更改

我有一个带有此代码适配器的自定义警报对话框

adapter_nomi = new ArrayAdapter<nomi>(context, R.layout.dialog_lista_nomi, R.id.r_dialog_nomi, list_nomi){

                    @Override
                    public View getView(int position, View convertView,ViewGroup parent) {
                            ViewHolder holder = null;
                            final String indirizzo;
                            if(convertView==null){
                                    LayoutInflater inflater = (LayoutInflater)getSystemService(Context.LAYOUT_INFLATER_SERVICE);
                                    convertView = inflater.inflate(R.layout.row_dialog_nomi, null);
                                    holder = new ViewHolder();
                                    holder.nome = (TextView)convertView.findViewById(R.id.r_dialog_nomi);
                                    convertView.setTag(holder);
                            }else{
                                    holder = (ViewHolder)convertView.getTag();
                            }
                            nomi item = getItem(position);
                            holder.nome.setText(item.get("nominativo"));
                            return convertView;
                    }
            };

但当列表名称更改，我调用showDialog时，它不是刷新。我还将代码适配器_nomi.notifyDataSetChange放入了onPrepareDialog；但它不起作用……为什么