Volley CallBack 方法没有给出响应？

如何解决Volley CallBack 方法没有给出响应？

我正在制作一个应用程序 GuesstheCelebrity。所以问题是我在响应方法之外需要名人姓名和他们的 imageUrls，所以我使用回调方法但它不起作用。首先我在 CelebDataService 类中获取数据，然后在 Main 活动中我使用 Matcher 和 Pattern 来获得所需的响应。我使用 Singleton 类向 requestQueue 添加请求。

这是我的代码：

凌空请求类

public class CelebDataService  {

Context context;
String response;
String url = "https://www.imdb.com/list/ls052283250/";

public CelebDataService(Context context) {
    this.context = context;
}

public interface CallBack {
    void onResponse(String response);
    void onError(String error);
}

public interface MatchListAsyncResponse {
    void processFinish(List<String> list);
}

public void getResponse(CallBack callBack)
{
    StringRequest stringRequest = new StringRequest(Request.Method.GET,url,new Response.Listener<String>() {
        @Override
        public void onResponse(String response) {
            System.out.println(response);
            callBack.onResponse(response);
        }
    },new Response.ErrorListener() {
        @Override
        public void onErrorResponse(VolleyError error) {
            callBack.onError(error.getMessage());
        }
    });
    MySingleton.getInstance(context).addToRequestQueue(stringRequest);
}

}

主要活动类

public class MainActivity extends AppCompatActivity {

ArrayList<String> urls = new ArrayList<>();
ArrayList<String> names = new ArrayList<>();
int cs = 0;
TextView textView;
ImageView imageView;
ImageRequest imageRequest;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main)

    textView = findViewById(R.id.textView);

    imageView = findViewById(R.id.imageView);

    CelebDataService celebDataService = new CelebDataService(MainActivity.this);
    celebDataService.getResponse(new CelebDataService.CallBack() {
        @Override
        public void onResponse(String response) {
            Log.i("hello","onResponse: " + response);
            String[] result = response.split("<div id=\"sidebar\">");
            Pattern p = Pattern.compile("src=\"(.*?)\"");
            Matcher m = p.matcher(result[0]);
            while (m.find())
            {
                urls.add(m.group(1));
            }
            p = Pattern.compile("alt=\"(.*?)\"");
            m = p.matcher(result[0]);
            while (m.find())
            {
                names.add(m.group(1));
            }
        }

        @Override
        public void onError(String error) {
            textView.setText(error);
        }
    });

    Random random = new Random();
    cs = random.nextInt(urls.size());

    imageRequest = new ImageRequest(urls.get(cs),new Response.Listener<Bitmap>() {
        @Override
        public void onResponse(Bitmap response) {
            imageView.setimageBitmap(response);
            requestQueue.stop();
        }
    },ImageView.ScaleType.CENTER_CROP,null,new Response.ErrorListener() {
        @Override
        public void onErrorResponse(VolleyError error) {
            textView.setText("Error");
            error.printstacktrace();
        }
    });
    MySingleton.getInstance(context).addToRequestQueue(imageRequest);
}

}

应用程序在启动时崩溃，因为 urls 数组列表为空。