Android Volley JSONObjectRequest在片段輸出什麼都沒有

我試圖建立一個ListView（誰是在片段內）與從外部網址獲取數據。Android Volley JSONObjectRequest在片段輸出什麼都沒有

我使用Volley來做這個請求，但是當我嘗試運行這個應用程序時，它什麼也沒有顯示。

這裏的片段代碼：

public class DashboardFragment extends Fragment { 
@Override 
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { 
    return inflater.inflate(R.layout.fragment_dashboard, container, false); 
} 

@Override 
public void onActivityCreated(Bundle savedInstanceState) { 
    super.onActivityCreated(savedInstanceState); 

    final List<NewsFeed> newsFeed = new ArrayList<>(); 

    JsonObjectRequest request = new JsonObjectRequest(Request.Method.GET, "http://webservice_url/", null, 
      new Response.Listener<JSONObject>() { 
       @Override 
       public void onResponse(JSONObject response) { 
        try { 
        JSONObject obj = response.getJSONObject("data"); 

        NewsFeed feed = new NewsFeed(obj.getString("title"), obj.getString("description"), obj.getString("date")); 
        newsFeed.add(feed); 
        } catch (JSONException e) { 
         e.printStackTrace(); 
        } 
       } 
      }, 
      new Response.ErrorListener() { 
       @Override 
       public void onErrorResponse(VolleyError error) { 
        error.printStackTrace(); 
       } 
      }); 

    RequestQueue requestQueue = Volley.newRequestQueue(getActivity()); 
    requestQueue.add(request); 

    ListView listView = (ListView) getActivity().findViewById(R.id.newsFeed); 
    NewsFeedAdapter adapter = new NewsFeedAdapter(getActivity(), (ArrayList<NewsFeed>) newsFeed); 
    listView.setAdapter(adapter); 
    } 
}

這裏是新聞源類和適配器：

public class NewsFeed { 
    public String title; 
    public String description; 
    public String date; 

    public NewsFeed(String title, String description, String date) { 
     this.title = title; 
     this.description = description; 
     this.date = date; 
    } 
} 

public class NewsFeedAdapter extends ArrayAdapter<NewsFeed> { 
    // View lookup cache 
    private class ViewHolder { 
     TextView title; 
     TextView description; 
     TextView date; 
    } 

    public NewsFeedAdapter(Context context, ArrayList<NewsFeed> newsFeedArrayList) { 
     super(context, R.layout.fragment_dashboard_news, newsFeedArrayList); 
    } 

    @Override 
    public View getView(int position, View convertView, ViewGroup parent) { 
     // Get the data item for this position 
     NewsFeed newsFeed = getItem(position); 

     // Check if an existing view is being reused, otherwise inflate the view 
     ViewHolder viewHolder; // view lookup cache stored in tag 

     if (convertView == null) { 
      viewHolder = new ViewHolder(); 
      LayoutInflater inflater = LayoutInflater.from(getContext()); 
      convertView = inflater.inflate(R.layout.fragment_dashboard_news, parent, false); 

      viewHolder.title = (TextView) convertView.findViewById(R.id.title); 
      viewHolder.description = (TextView) convertView.findViewById(R.id.description); 
      viewHolder.date = (TextView) convertView.findViewById(R.id.date); 

      convertView.setTag(viewHolder); 
     } else { 
      viewHolder = (ViewHolder) convertView.getTag(); 
     } 

     viewHolder.title.setText(newsFeed.title); 
     viewHolder.description.setText(newsFeed.description); 
     viewHolder.date.setText(newsFeed.date); 

     return convertView; 
    } 
}

此外，當我添加而不排球元件請求它的工作。

來源

2015-11-29 Manu

在'onResponse（）'你需要更新listView。在填充'newsFeed'後立即執行'adapter.notifyDataSetChanged（）'。試試吧:) – rafid059

先生，你做了我的一天！這是現在完美的工作，謝謝！ – Manu

我將添加此作爲答案然後:) – rafid059

Original Comment

在onResponse()您需要更新列表視圖。填寫完newsFeed之後再做adapter.notifyDataSetChanged()。試試吧:)

來源

2015-11-29 15:40:24 rafid059

Android Volley JSONObjectRequest在片段輸出什麼都沒有

回答

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