Android studio：无法使用Direct line Rest API连接Microsoft bot

Question

我正在尝试在我的应用中构建聊天机器人。但我无法将Microsoft bot与Direct line Rest API连接到应用程序，下面是我连接机器人的代码。它给了我FileNotFoundException，但我真的不知道该怎么做。有人帮助我吗？

[MvxFragment(typeof(MainViewModel), Resource.Id.content_frame, true)]
public class SecondFragment : BaseFragment<SecondViewModel>, View.IOnTouchListener
{ 
    private void DoSwipe(string swipeText)
    {
        if (swipeText.Equals("LEFT"))
        {
            FragmentManager.BeginTransaction()
                .SetCustomAnimations(Resource.Animation.slide_from_left, Resource.Animation.slide_from_right)
                .Replace(Resource.Id.content_frame,ThirdFragment.NewInstance(null))
                .Commit();
        }
        if (swipeText.Equals("RIGHT"))
        {
            ...
        }

        ViewModel.SwipeView(swipeText);
    }
}

例外：

private String startConversation() {
    String primaryToken = "ABC";
    StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
    StrictMode.setThreadPolicy(policy);

    String UrlText = " https://directline.botframework.com/api/tokens/conversation";
    URL url = null;
    String responseValue = "";

    try {
        url = new URL(UrlText);
    } catch (MalformedURLException e) {
        e.printStackTrace();
    }
    HttpURLConnection urlConnection = null;
    try {
        String basicAuth = "Bearer " + primaryToken;
        urlConnection = (HttpURLConnection) url.openConnection();
        urlConnection.setRequestProperty("Authorization", basicAuth);
        urlConnection.setRequestMethod("POST");
        urlConnection.setRequestProperty("Content-Type", "application/json");
    } catch (IOException e) {
        e.printStackTrace();
    }
    try {
        InputStream in = new BufferedInputStream(urlConnection.getInputStream());
        responseValue = readStream(in);
    } catch (Exception e) {
        e.printStackTrace();
    } finally {
        urlConnection.disconnect();
    }

    return responseValue;//returns the conversationID and token
}