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我试图ListView在下载JSON数据后更新数据，但它没有用，因为onCreate方法onCreateView只在第一次工作。当我将调试点指向这两种方法时，我注意到了这一点，但调试行从未进入那里。响应 json 正确，但无法通过解析更新 UI ListViewFragment.init(myNewDataList)。这是我的 ListViewFragment，

public class ListViewFragment extends Fragment{

  ListView listView;

  ArrayList<Incident> incidentLists;

  public static ListViewFragment init(ArrayList<Incident> incidentLists) {
    ListViewFragment listViewFragment = new ListViewFragment();
    listViewFragment.setIncientLists(incidentLists);
    return listViewFragment;
  }

  @Override
  public void onCreate(Bundle savedInstanceState) {
    // TODO Auto-generated method stub
    super.onCreate(savedInstanceState);
  }

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

    initUI(view);
    adapter = new ListViewAdapter(getActivity(), incidentLists);
    adapter.notifyDataSetChanged();
    listView.setAdapter(adapter);
    return view;
  }

  public ArrayList<Incident> getIncientLists() {
    return incidentLists;
  }

  public void setIncientLists(ArrayList<Incident> incientLists) {
    this.incidentLists = incientLists;
  }

}

在 JSON 下载后，我将数据解析为片段，如下面的片段，这是AsyncHttpClient'sonSuccess方法。

@Override
public void onSuccess(int statusCode, Header[] headers,
    String content) {
    try {
        ArrayList<Incident> incidentList = new ArrayList<Incident>();
        JSONObject content_ = new JSONObject(content);
        JSONArray response = content_.getJSONArray("nodes");
        for (int i = 0; i < response.length(); i++) {
            JSONObject nodeObj = response.getJSONObject(i)
                .getJSONObject("node");
            Incident incident = Utils.parseNodeObjectToIncident(nodeObj);
            incidentList.add(incident);
        }
        Fragment fragment = ListViewFragment.init(incidentList);
        Utils.replaceFragment(fragment, MainActivity.this);
    } catch (JSONException e) {
        Toast.makeText(getApplicationContext(),"JSON Exception", Toast.LENGTH_LONG).show();
    }
}

我怀疑我的 ListViewFragment 第一次只发生一次，因为它与Utils.replaceFragment() 中的BackStack和事务内容混淆。

public static void replaceFragment(Fragment fragment,
            AppCompatActivity activity) {
        String backStateName = fragment.getClass().getName();
        String fragmentTag = backStateName;
        FragmentManager fragmentManager = activity.getSupportFragmentManager();
        boolean fragmentPopped = fragmentManager.popBackStackImmediate(
                backStateName, 0);
        if (!fragmentPopped
                && fragmentManager.findFragmentByTag(fragmentTag) == null) {
            FragmentTransaction fragmentTransaction = fragmentManager
                    .beginTransaction();
            fragmentTransaction.replace(R.id.frame_container, fragment,
                    fragmentTag);
            // fragmentTransaction.add(R.id.frame_container, fragment);
            fragmentTransaction
                    .setTransition(FragmentTransaction.TRANSIT_FRAGMENT_FADE);
            fragmentTransaction.addToBackStack(backStateName);
            // fragmentTransaction.commitAllowingStateLoss();
            fragmentTransaction.commitAllowingStateLoss();
        }
    }

有什么帮助吗？

4

1 回答 1

1

基本上，您的问题是当您从服务器获得最新信息集时，您无法更新列表。我会用下面的代码解决这个问题：

在列表视图适配器中保留如下所示的方法：

public class ListFragmentAdapter extends <your adapter extension>{

private Context context;
private List<Incident> incidents;
//constructor
public ListFragmentAdapter (Context context,List<Incident> initialIncidentList){

this.context = context;
this.incidents = initialIncidentList;
}
public void updateListFragment(List<Incident> latestIncidents){
incidents.addAll(latestIncidents);
this.notifyDataSetChanged();
}
}

如果您有任何疑问，请在下方评论

于 2016-01-11T04:56:55.770 回答