Question

我一直在尝试将Json解析为A ListView，但是当我这样做时，我得到了;

03-04 14:43:45.345: E/log_tag(16519): Error parsing data org.json.JSONException: No value for items

它以某种方式无法从Json对象中获取项目。

这是我用于它的代码;

getJSON.java

  import java.io.BufferedReader;
    import java.io.InputStream;
    import java.io.InputStreamReader;

    import org.apache.http.HttpEntity;
    import org.apache.http.HttpResponse;
    import org.apache.http.client.HttpClient;
    import org.apache.http.client.methods.HttpPost;
    import org.apache.http.impl.client.DefaultHttpClient;
    import org.json.JSONException;
    import org.json.JSONObject;

    import android.util.Log;

    public class getJSON {

        public static JSONObject getJSONfromURL(String url){
            InputStream is = null;
            String result = "";
            JSONObject jArray = null;

            //http post
            try{
                    HttpClient httpclient = new DefaultHttpClient();
                    HttpPost httppost = new HttpPost(url);
                    HttpResponse response = httpclient.execute(httppost);
                    HttpEntity entity = response.getEntity();
                    is = entity.getContent();

            }catch(Exception e){
                    Log.e("NO CONNECTION", "Error in http connection "+e.toString());
            }

          //convert response to string
            try{
                    BufferedReader reader = new BufferedReader(new InputStreamReader(is,"iso-8859-1"),8);
                    StringBuilder sb = new StringBuilder();
                    String line = null;
                    while ((line = reader.readLine()) != null) {
                            sb.append(line + "\n");
                    }
                    is.close();
                    result=sb.toString();
            }catch(Exception e){
                    Log.e("CANT CONVERT DATA", "Error converting result "+e.toString());
            }

            try{

                jArray = new JSONObject(result);            
            }catch(JSONException e){
                    Log.e("CANT READ DATA", "Error parsing data "+e.toString());
            }

            return jArray;
        }
}

和

listview.java

@Override
    protected void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);
        setContentView(R.layout.listplaceholder);
        ArrayList<HashMap<String, String>> mylist = new ArrayList<HashMap<String, String>>();

        //Get the data (see above)
        JSONObject json = getJSON.getJSONfromURL("http://gdata.youtube.com/feeds/api/users/UKFDubstep/uploads?v=2&alt=jsonc");


               try{



                   final JSONArray array = json.getJSONArray("items");

                        //Loop the Array
                for(int i=0;i < array.length();i++){                        

                    HashMap<String, String> map = new HashMap<String, String>();
                    JSONObject e = array.getJSONObject(i);

                    map.put("id",  String.valueOf(i));
                    map.put("title", "" + e.getString("title"));
                    map.put("viewCount", "Views: " +  e.getString("viewCount"));
                    mylist.add(map);
            }
               }catch(JSONException e)        {
                 Log.e("log_tag", "Error parsing data "+e.toString());
               }

               ListAdapter adapter = new SimpleAdapter(this, mylist , R.layout.dubstep,
                       new String[] { "title", "viewCount" },
                       new int[] { R.id.item_title, R.id.item_subtitle });

       setListAdapter(adapter);

       final ListView lv = getListView();
       lv.setTextFilterEnabled(true);
       lv.setOnItemClickListener(new OnItemClickListener() {
        public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
            @SuppressWarnings("unchecked")
            HashMap<String, String> o = (HashMap<String, String>) lv.getItemAtPosition(position);
            Toast.makeText(dubstep.this, "ID '" + o.get("id") + "' was clicked.", Toast.LENGTH_SHORT).show(); 

            }
        });

    }

我不知道它出了什么问题。

有任何帮助吗？感谢。

编辑： json输出

03-04 15:30:29.955: I/json(19109): {"error":{"message":"Response contains no content type","errors":[{"internalReason":"Response contains no content type","domain":"GData","code":"missingContentType"}],"code":400},"apiVersion":"2.1"}

编辑json链接; http：//gdata.youtube.com/feeds/api/users/UKFDubstep/uploads？v = 2＆amp; alt = jsonc

Answer 1

通过查看JSON结果（打开你的示例url），我看到'items'在另一个JSONObject中。所以我相信你需要这样做：

JSONObject data = json.getJSONObject('data');
JSONArray array = data.getJSONArray('items');

Answer 2

你不需要getJSON.java，只有你应该做的才能使它工作：

    private static String URL = "http://gdata.youtube.com/feeds/api/users/UKFDubstep/uploads?v=2&alt=jsonc";
@Override
protected void onCreate(Bundle savedInstanceState) {
    // TODO Auto-generated method stub
    super.onCreate(savedInstanceState);
    setContentView(R.layout.listplaceholder);

    ArrayList<HashMap<String, String>> mylist = new ArrayList<HashMap<String, String>>();

        try{                   
               HttpClient  httpclient = new DefaultHttpClient();
               httpclient.getParams().setParameter(CoreProtocolPNames.PROTOCOL_VERSION, HttpVersion.HTTP_1_1);
               HttpGet request = new HttpGet(URL);
               HttpResponse response = httpclient.execute(request);
               HttpEntity resEntity = response.getEntity();
               String _response = EntityUtils.toString(resEntity); // content will be consume only once
               Log.i(".......",_response);
               JSONObject json = new JSONObject(_response);
               JSONArray jarray = json.getJSONArray("items");                     
                    //Loop the Array
               for(int i=0;i < array.length();i++){                        

                   HashMap<String, String> map = new HashMap<String, String>();
                   JSONObject e = array.getJSONObject(i);

                   map.put("id",  String.valueOf(i));
                   map.put("title", "" + e.getString("title"));
                   map.put("viewCount", "Views: " +  e.getString("viewCount"));
                   mylist.add(map);
        }
           }catch(JSONException e)        {
             Log.e("log_tag", "Error parsing data "+e.toString());
           }

           ListAdapter adapter = new SimpleAdapter(this, mylist , R.layout.dubstep,
                   new String[] { "title", "viewCount" },
                   new int[] { R.id.item_title, R.id.item_subtitle });

   setListAdapter(adapter);

   final ListView lv = getListView();
   lv.setTextFilterEnabled(true);
   lv.setOnItemClickListener(new OnItemClickListener() {
    public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
        @SuppressWarnings("unchecked")
        HashMap<String, String> o = (HashMap<String, String>) lv.getItemAtPosition(position);
        Toast.makeText(dubstep.this, "ID '" + o.get("id") + "' was clicked.",  Toast.LENGTH_SHORT).show(); 

        }
    });

}

但是现在你应该解析JSON数据不应该在UI线程中执行。您需要扩展AsyncTask并在doInBackgound（）方法中执行该工作，因此您可以在单独的线程中进行解析，而不是在UI中进行解析... AsyncTask

Android：在Listview中解析Json

2 个答案: