片段的自定义ListView只是在旋转Android Phone时出现

Question

I have created an Fragment to be the main feed of my app. The list data(ArrayList) is loaded from the main activity through the inner interface in fragment that Activity implements.

My problems:

1. My custom ListView just is shown when I rotate de phone.
2. OnCreateView and OnActivityCreate is called twice when I rotate.
3. If ListView is shown after I rotate the phone and I click in, i get next error:

java.lang.IllegalStateException: The content of the adapter has changed but ListView did not receive a notification. Make sure the content of your adapter is not modified from a background thread, but only from the UI thread. Make sure your adapter calls notifyDataSetChanged() when its content changes. [in ListView(2131034209, class android.widget.ListView) with Adapter(class com.fb.newcomersapp.CustomListAdapter)]

That is my main fragment methods:

public void onActivityCreated(Bundle savedInstanceState) {
    // TODO Auto-generated method stub
    super.onActivityCreated(savedInstanceState);
    listView = (ListView) getView().findViewById(R.id.event_list_view);
    mCallback.parseQueryEvents();
    ArrayList<Event> eventList = mCallback.getEventList();
    Log.d("FeedActivity", eventList.size()+"");
    CustomListAdapter adapter = new CustomListAdapter(getActivity(), eventList);
    listView.setAdapter(adapter);

    listView.setOnItemClickListener(new OnItemClickListener() {

        @Override
        public void onItemClick(AdapterView<?> parent, View view,
                int position, long id) {
            // TODO Auto-generated method stub
            mCallback.openEvent(position);

        }
    });

public View onCreateView(LayoutInflater inflater, ViewGroup container,
        Bundle savedInstanceState) {
    // TODO Auto-generated method stub
    View view = inflater.inflate(R.layout.fragment_feed, container, false);

    textView = (TextView) view.findViewById(R.id.tv_header);
    textView.setText(mCallback.getLocal()); 
    return view;
}

The main activity methods:

public void parseQueryEvents () {
    eventList = new ArrayList<Event>();
    ParseQuery<ParseObject> query = ParseQuery.getQuery("Event");
    query.orderByAscending("startDate") ;
    query.whereGreaterThanOrEqualTo("endDate", new Date()) ;
    query.findInBackground(new FindCallback<ParseObject>() {
        public void done(List<ParseObject> parseEventList, ParseException e) {
            if (e == null) {
                ParseObject temp ;
                Iterator<ParseObject> i = parseEventList.iterator() ;
                while(i.hasNext()) {
                    temp = i.next();
                    eventList.add(new Event(temp)) ;
                }
            } else {
                Log.d("FeedActivity", e.getMessage());
            }
        }
    });
}

public ArrayList<Event> getEventList() {
    // TODO Auto-generated method stub
    return eventList;
}

Log:

02-04 13:36:06.844: D/GPS(7237): GPS 02-04 13:36:07.110: D/FeedActivity(7237): 0 02-04 13:36:07.145: D/GPS(7237): GPS 02-04 13:36:07.409: D/FeedActivity(7237): 0 02-04 13:36:07.420: I/Choreographer(7237): Skipped 39 frames! The application may be doing too much work on its main thread. 02-04 13:36:07.451: W/View(7237): requestLayout() improperly called by android.widget.ListView{42079068 IFED.VC. ......ID -360,0-0,778 #7f050041 app:id/list_slidermenu} during layout: running second layout pass

So, anyone can help me? Thx :D

Answer 1

I ran into this problem a while ago when dealing with orientation changes. Sorry for not giving a full answer atm, but basically save the adapter (as well as the ListView if you'd like) as a class variable. Then, inside onActivityCreated, put the lines about creating and setting the adapter in a if statement checking if the adapter is null or not. So, something like this...

private CustomListAdapter mAdapter; // Add this variable

public void onActivityCreated(Bundle savedInstanceState) {
    // TODO Auto-generated method stub
    super.onActivityCreated(savedInstanceState);
    listView = (ListView) getView().findViewById(R.id.event_list_view);
    mCallback.parseQueryEvents();
    ArrayList<Event> eventList = mCallback.getEventList();
    Log.d("FeedActivity", eventList.size()+"");

    // Add this conditional
    if(mAdapter == null) {
       CustomListAdapter adapter = new CustomListAdapter(getActivity(), eventList);
       listView.setAdapter(adapter);
    }

    listView.setOnItemClickListener(new OnItemClickListener() {

        @Override
        public void onItemClick(AdapterView<?> parent, View view,
                int position, long id) {
            // TODO Auto-generated method stub
            mCallback.openEvent(position);

        }
    }
}

I believe the issue originates somewhere along the line where it's trying to save us all some time by caching variables (like views with ids such as the ListView) when recreating the Activity+Fragment- however, in the midst of all that, setting a new adapter causes an issue.