setOnItemClickListener для исключения списка listview

Question

При щелчке по списку приложение вызывает какое-то исключение. Почему это так? Ниже мой код.

класс LoadProfile расширяет AsyncTask {

@Override 
    protected void onPreExecute() { 
     super.onPreExecute(); 
    } 

    protected String doInBackground(String... args) { 
     // Building Parameters 
     String json = null; 
     PROFILE_URL = "http://www.example.com/list_chat_single_android.php?from_pin="+pin; 

     try { 
      List<NameValuePair> params = new ArrayList<NameValuePair>(); 

      HttpClient httpclient = new DefaultHttpClient(); 
      HttpPost httppost = new HttpPost(PROFILE_URL); 
      httppost.setEntity(new UrlEncodedFormEntity(params)); 

      // Execute HTTP Post Request 
      HttpResponse response = httpclient.execute(httppost); 
      HttpEntity resEntity = response.getEntity(); 
      json = EntityUtils.toString(resEntity); 

      Log.i("Chat list: ", json.toString()); 

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

     return json; 
    } 

    @Override 
    protected void onPostExecute(String json) { 
     super.onPostExecute(json); 
     try{ 
     chat_all = new JSONObject(json); 
     final ArrayList<HashMap<String, String>> arraylist = new ArrayList<HashMap<String, String>>(); 
     JSONArray user = chat_all.getJSONArray("chat_all"); 
     String contains=json.toString(); 

     if(contains.contains("name")) 
     { 
      tv1.setVisibility(View.GONE); 
      for (int i = 0; i < user.length(); i++) { 
       JSONObject object = user.getJSONObject(i); 

       HashMap<String, String> map = new HashMap<String, String>(); 
       map.put("name", object.getString("name")); 
       name=object.getString("name"); 
       to_t=object.getString("to_t");; 
       map.put("msg", object.getString("msg")); 
       map.put("time_t", object.getString("time_t")); 
       map.put("photo", "http://www.example.com/"+object.getString("photo")); 
       arraylist.add(map);  
      } 

      String[] from = {"name", "msg", "time_t", "photo"}; 
      int[] to = {R.id.textView1, R.id.textView2, R.id.textView3, R.id.imageView1}; 

      ListAdapter adapterss = new ChatAdapter(ChatSingle.this,arraylist,R.layout.chat_single_list,from,to); 
      lv1.setAdapter(adapterss); 

      lv1.setOnItemClickListener(new OnItemClickListener() { 

       @Override 
       public void onItemClick(AdapterView<?> arg0, View arg1, 
         int arg2, long arg3) { 
        // TODO Auto-generated method stub 
        /*Intent i=new Intent(ChatSingle.this,ChatSingle_start.class); 
        i.putExtra("name", name); 
        i.putExtra("from_pin", pin); 
        i.putExtra("to", to_t); 
        startActivity(i);*/ 
        MatrixCursor matrix = (MatrixCursor)arg0.getItemAtPosition(arg2); 

        String selection = matrix.getString(arg2); 
        Log.d("Position:-",selection); 
       } 
      }); 
     } 
     else 
     { 
      tv1.setText("No chat yet!"); 
     } 

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

    } 
} 

Ниже исключение брошенного моего приложения.

03-07 15:29:16.849: E/AndroidRuntime(2006): FATAL EXCEPTION: main 
03-07 15:29:16.849: E/AndroidRuntime(2006): java.lang.ClassCastException: java.util.HashMap cannot be cast to android.database.MatrixCursor 
03-07 15:29:16.849: E/AndroidRuntime(2006):  at com.event.ChatSingle$1.onItemClick(ChatSingle.java:63) 
03-07 15:29:16.849: E/AndroidRuntime(2006):  at android.widget.AdapterView.performItemClick(AdapterView.java:292) 
03-07 15:29:16.849: E/AndroidRuntime(2006):  at android.widget.AbsListView.performItemClick(AbsListView.java:1058) 
03-07 15:29:16.849: E/AndroidRuntime(2006):  at android.widget.AbsListView$PerformClick.run(AbsListView.java:2514) 
03-07 15:29:16.849: E/AndroidRuntime(2006):  at android.widget.AbsListView$1.run(AbsListView.java:3168) 
03-07 15:29:16.849: E/AndroidRuntime(2006):  at android.os.Handler.handleCallback(Handler.java:605) 
03-07 15:29:16.849: E/AndroidRuntime(2006):  at android.os.Handler.dispatchMessage(Handler.java:92) 
03-07 15:29:16.849: E/AndroidRuntime(2006):  at android.os.Looper.loop(Looper.java:137) 
03-07 15:29:16.849: E/AndroidRuntime(2006):  at android.app.ActivityThread.main(ActivityThread.java:4340) 
03-07 15:29:16.849: E/AndroidRuntime(2006):  at java.lang.reflect.Method.invokeNative(Native Method) 
03-07 15:29:16.849: E/AndroidRuntime(2006):  at java.lang.reflect.Method.invoke(Method.java:511) 
03-07 15:29:16.849: E/AndroidRuntime(2006):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784) 
03-07 15:29:16.849: E/AndroidRuntime(2006):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551) 
03-07 15:29:16.849: E/AndroidRuntime(2006):  at dalvik.system.NativeStart.main(Native Method) 

Зачем нужна эта ошибка. Я понятия не имею, как его решить. Может ли кто-нибудь знать решение.

Answer 1

Ваш реализация возвращает экземпляр HashMap, а не MatrixCursor. Изменение

MatrixCursor matrix = (MatrixCursor)arg0.getItemAtPosition(arg2); 

к

HashMap<String, String> matrix = (HashMap<String, String>)arg0.getItemAtPosition(arg2);