在擴展片段中使用ListAdapter失敗

Question

我試圖將JSON數據更新爲ListView。使用ListAdapter時失敗。片段不允許嗎？我堅持要使用擴展片段。有什麼方法嗎？

請幫幫我。謝謝。

這是整個代碼的一部分。

public class ScheduleFragment extends Fragment { 


    public ProgressDialog pDialog; 

    private ListView myListView; 

    // Creating JSON Parser object 
    JSONParser jParser = new JSONParser(); 

    ArrayList<HashMap<String, String>> subjectList;  

    // url to get all subjects list 
    private static String url_all_subjects = "http://192.168.1.12/android_project/get_subjects.php"; 

    // JSON Node names 
    private static final String TAG_SUCCESS = "success"; 
    private static final String TAG_STUDENT = "students"; 
    private static final String TAG_MATRIX_ID = "matrix"; 
    private static final String TAG_NAME = "name"; 

    // subject JSONArray 
    JSONArray subject = null; 


public ScheduleFragment(){} 

@Override 
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) 
{ 
    View rootView = inflater.inflate(R.layout.fragment_schedule, container, false); 



//------------------------------------CREATING A LISTVIEW----------------------- 

    // Loading subject in Background Thread 
    new LoadAllSubject().execute(); 

// Hashmap for ListView 
    subjectList = new ArrayList<HashMap<String, String>>(); 

    myListView = (ListView) rootView.findViewById(R.id.textViewMatrix); 

    // on selecting single subject 
    myListView.setOnItemClickListener(new OnItemClickListener() { 

     @Override 
     public void onItemClick(AdapterView<?> parent, View view, 
       int position, long id) { 
      // getting values from selected ListItem 
      String matrix_id = ((TextView) view.findViewById(R.id.textViewMatrix)).getText() 
        .toString(); 

      // Starting new intent 
      Intent in = new Intent(getActivity().getApplicationContext(), 
        SingleSubject.class); 

      // sending matrix id to next activity 
      in.putExtra(TAG_MATRIX_ID, matrix_id); 

      // starting new activity and expecting some response back 
      startActivityForResult(in, 100); 
     } 
    }); 

    return rootView; 
} 

/** 
* Background Async Task to Load all product by making HTTP Request 
* */ 
class LoadAllSubject extends AsyncTask<String, String, String> { 

    /** 
    * Before starting background thread Show Progress Dialog 
    * */ 

    @Override 
    protected void onPreExecute() { 
     super.onPreExecute(); 
     pDialog = ProgressDialog.show(ScheduleFragment.this.getActivity(), "Progress", "Loading subjects. Please wait...", false); 
     //pDialog.setMessage("Loading subjects. Please wait..."); 
     pDialog.setIndeterminate(false); 
     pDialog.setCancelable(false); 
    } 

    /** 
    * getting All products from url 
    * */ 
    protected String doInBackground(String... args) { 
     // Building Parameters 
     List<NameValuePair> params = new ArrayList<NameValuePair>(); 
     // getting JSON string from URL 
     JSONObject json = jParser.makeHttpRequest(url_all_subjects, "GET", params); 

     // Check your log cat for JSON reponse 
     Log.d("All Products: ", json.toString()); 

     try { 
      // Checking for SUCCESS TAG 
      int success = json.getInt(TAG_SUCCESS); 

      if (success == 1) { 
       // products found 
       // Getting Array of Subject 
       subject = json.getJSONArray(TAG_STUDENT); 

       // looping through All Subjects 
       for (int i = 0; i < subject.length(); i++) { 
        JSONObject c = subject.getJSONObject(i); 

        // Storing each json item in variable 
        String id = c.getString(TAG_MATRIX_ID); 
        String name = c.getString(TAG_NAME); 

        // creating new HashMap 
        HashMap<String, String> map = new HashMap<String, String>(); 

        // adding each child node to HashMap key => value 
        map.put(TAG_MATRIX_ID, id); 
        map.put(TAG_NAME, name); 

        // adding HashList to ArrayList 
        subjectList.add(map); 
       } 
      } else { 
       // no products found 
       // Launch Add New product Activity 

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

     return null; 
    } 

    /** 
    * After completing background task Dismiss the progress dialog 
    * **/ 
    protected void onPostExecute(String file_url) { 
     // dismiss the dialog after getting all products 
     pDialog.dismiss(); 
     // updating UI from Background Thread 
      public void run() { 
       /** 
       * Updating parsed JSON data into ListView 
       * */ 
       ListAdapter adapter = new SimpleAdapter(
         getActivity(), subjectList, 
         R.layout.all_subject, new String[] { TAG_MATRIX_ID, 
           TAG_NAME}, 
         new int[] { R.id.matrix_id, R.id.name }); 
       // updating listview 
       myListView.setListAdapter(adapter); 
      } 


    } 

} 

} 

這是all_subject.xml

<!-- Subject matrix_id - will be HIDDEN - used to pass to other activity --> 
<TextView 
    android:id="@+id/matrix_id" 
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content" 
    android:visibility="gone" /> 


<!-- Name Label --> 
<TextView 
    android:id="@+id/name" 
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content" 
    android:paddingTop="6dip" 
    android:paddingLeft="6dip" 
    android:textSize="17dip" 
    android:textStyle="bold" /> 

Answer 1

您需要延長ListFramgent。 setListAdapter是ListFragment的一種方法。不需要使用runOnUiThread。在ui線程上調用onPostExecute。

編輯：

@Override 
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) 
{ 
    View rootView = inflater.inflate(R.layout.fragment_schedule, container, false); 
    subjectList = new ArrayList<HashMap<String, String>>(); 
    myListView = (ListView) rootView.findViewById(R.id.textViewMatrix); 
    new LoadAllSubject().execute(); 
    myListView.setOnItemClickListener(new OnItemClickListener() { 

     @Override 
     public void onItemClick(AdapterView<?> parent, View view, 
       int position, long id) { 
      String matrix_id = ((TextView) view.findViewById(R.id.textViewMatrix)).getText() 
        .toString(); 

      // Starting new intent 
      Intent in = new Intent(getActivity().getApplicationContext(), 
        SingleSubject.class); 

      // sending matrix id to next activity 
      in.putExtra(TAG_MATRIX_ID, matrix_id); 

      // starting new activity and expecting some response back 
      startActivityForResult(in, 100); 
     } 
    }); 

    return rootView; 
} 

然後

protected void onPostExecute(String file_url) { 
    super.onPostExecute(file_url); 
    pDialog.dismiss(); 
    ListAdapter adapter = new SimpleAdapter(
         getActivity(), subjectList, 
        R.layout.all_subject, new String[] { TAG_MATRIX_ID, 
          TAG_NAME}, 
        new int[] { R.id.matrix_id, R.id.name }); 
    myListView.setAdapter(adapter); 
    }