jsonObject解析问题“org.json.JSONException：缩略图没有值”

Question

我将json解析到我的Android应用程序时遇到了一些问题 我想获得缩略图URL和videoId，但它显示缩略图JSONException没有值，
videoId发生了同样的情况 我能怎么做？请帮忙

这是我的json文件和片段活动的样子：

请求网址：

   GET https://www.googleapis.com/youtube/v3/playlists?part=snippet&channelId=UC_x5XG1OV2P6uZZ5FSM9Ttw&maxResults=1&key={YOUR_API_KEY}    

json回复：

    {   
     "kind": "youtube#playlistListResponse",  
     "etag": "\"iDqJ1j7zKs4x3o3ZsFlBOwgWAHU/QnDwmfxnHa--I54eAlcSQNwG2Ok\"",
     "nextPageToken": "CAEQAA",  
     "pageInfo": {  
      "totalResults": 291,  
      "resultsPerPage": 1  
     },  
     "items": [  
      {  
       "kind": "youtube#playlist",  
       "etag":"\"iDqJ1j7zKs4x3o3ZsFlBOwgWAHU/IB0XO8J78ybZZvHQq59Q2Y8WoFI\"",  
       "id": "PLOU2XLYxmsIJ79h65LUPZarLyVmuI-I7b",  
       "snippet": {  
       "publishedAt": "2015-07-17T18:59:08.000Z",  
       "channelId": "UC_x5XG1OV2P6uZZ5FSM9Ttw",  
"title": "This week on Google Developers 7/11/15 - 7/17/15",  
"description": "",  
"thumbnails": {  
 "default": {  
  "url": "https://i.ytimg.com/vi/ygFe9Pj5N60/default.jpg",  
  "width": 120,  
  "height": 90  
 },  
 "medium": {  
  "url": "https://i.ytimg.com/vi/ygFe9Pj5N60/mqdefault.jpg",  
  "width": 320,  
  "height": 180  
 },  
    "position": 0,  
    "resourceId": {  
      "videoId": "1_hgNNFAfm4"  
        }  
   }  
  }  
 ]  
}  

片段活动jsonResponse代码：

   private void parseJSONReaponse(JSONObject response) {  
    if (response == null || response.length() == 0) {   
        return;  
    }  
    try {  
        StringBuilder data = new StringBuilder();
        JSONArray arrayItems = response.getJSONArray(KEY_ITEMS);

        for (int i = 0; i < arrayItems.length(); i++) {
            JSONObject currentItems = arrayItems.getJSONObject(i);
            String id = currentItems.getString(KEY_ID);
            //data.append(id + "\n");
            JSONObject objectSnippet = currentItems.getJSONObject(KEY_SNIPPET);
            String title = null;
            if (objectSnippet.has(KEY_TITLE)) {
                title = objectSnippet.getString(KEY_TITLE);
            }
            else {
                title = "NA";
            }
            //data.append(id + title + "\n\n");

            JSONObject objectThumbnail = objectSnippet.getJSONObject(KEY_THUMBNAIL);
            JSONObject objectThumbnailMedium = objectThumbnail.getJSONObject(KEY_THUMBNAIL_MEDIUM);
            String urlThumbnail = null;
            if (objectThumbnailMedium.has(KEY_THUMBNAIL_MEDIUM)) {
                urlThumbnail = objectThumbnailMedium.getString(KEY_THUMBNAIL_MEDIUM_URL);
            }

            JSONObject objectResourceId = objectSnippet.getJSONObject(KEY_RESOURCEID);
            String resourceID = null;
            if (objectResourceId.has(KEY_VIDEOID)){
                resourceID = objectResourceId.getString(KEY_VIDEOID);
            }

            VideoData videoData = new VideoData();
            videoData.setTitle(title);
            videoData.setUrlThumbnail(urlThumbnail);
            videoData.setVideoId(resourceID);

            listVideos.add(videoData);

            data.append(id + title + urlThumbnail + resourceID +"\n\n");

        }

        L.T(getActivity(),listVideos.toString());
    //            L.T(getActivity(),data.toString());

    } catch (JSONException e) {
        e.printStackTrace();
    }
}

这里是LogCat Msgs

    07-18 01:11:25.075    1823-1823/com.example.example W/System.err﹕ org.json.JSONException: No value for thumbnails    
   07-18 01:11:25.075    1823-1823/com.example.example W/System.err﹕ at org.json.JSONObject.get(JSONObject.java:389)    
   07-18 01:11:25.075    1823-1823/com.example.example W/System.err﹕ at org.json.JSONObject.getJSONObject(JSONObject.java:609)    
   07-18 01:11:25.075    1823-1823/com.example.example W/System.err﹕ at com.example.example.fragment.VideoTabFragment.parseJSONReaponse(VideoTabFragment.java:110)    
   07-18 01:11:25.075    1823-1823/com.example.example W/System.err﹕ at com.example.example.fragment.VideoTabFragment.access$000(VideoTabFragment.java:31)    
   07-18 01:11:25.075    1823-1823/com.example.example W/System.err﹕ at com.example.example.fragment.VideoTabFragment$1.onResponse(VideoTabFragment.java:75)    
   07-18 01:11:25.076    1823-1823/com.example.example W/System.err﹕ at com.example.example.fragment.VideoTabFragment$1.onResponse(VideoTabFragment.java:71)    
   07-18 01:11:25.076    1823-1823/com.example.example W/System.err﹕ at com.android.volley.toolbox.JsonRequest.deliverResponse(JsonRequest.java:65)    
   07-18 01:11:25.076    1823-1823/com.example.example W/System.err﹕ at com.android.volley.ExecutorDelivery$ResponseDeliveryRunnable.run(ExecutorDelivery.java:99)    
   07-18 01:11:25.076    1823-1823/com.example.example W/System.err﹕ at android.os.Handler.handleCallback(Handler.java:739)    
   07-18 01:11:25.076    1823-1823/com.example.example W/System.err﹕ at android.os.Handler.dispatchMessage(Handler.java:95)    
   07-18 01:11:25.076    1823-1823/com.example.example W/System.err﹕ at android.os.Looper.loop(Looper.java:135)    
   07-18 01:11:25.076    1823-1823/com.example.example W/System.err﹕ at android.app.ActivityThread.main(ActivityThread.java:5254)    
   07-18 01:11:25.076    1823-1823/com.example.example W/System.err﹕ at java.lang.reflect.Method.invoke(Native Method)    
   07-18 01:11:25.076    1823-1823/com.example.example W/System.err﹕ at java.lang.reflect.Method.invoke(Method.java:372)    
   07-18 01:11:25.076    1823-1823/com.example.example W/System.err﹕ at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903)    
   07-18 01:11:25.076    1823-1823/com.example.example W/System.err﹕ at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698)