java.lang.IllegalStateException - why??? (Android, ListAdapter)

Time to time users get following exception (I myself can't reproduce it):

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. [in ListView(2131165209, class android.widget.ListView) with Adapter(class com.tfd.mobile.TfdSearch.TfdSearch$SearchList$PagesListAdapter)]
at android.widget.ListView.layoutChildren(ListView.java:1567)
at android.widget.AbsListView.onTouchModeChanged(AbsListView.java:2093)
at android.view.ViewTreeObserver.dispatchOnTouchModeChanged(ViewTreeObserver..java:591)
at android.view.ViewRoot.ensureTouchModeLocally(ViewRoot.java:2023)
at android.view.ViewRoot.ensureTouchMode(ViewRoot.java:2007)
at android.view.ViewRoot.handleMessage(ViewRoot.java:1775)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:123)
at android.app.ActivityThread.main(ActivityThread.java:4633)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:521)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:858)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
at dalvik.system.NativeStart.main(Native Method)

I can't find why it happened. I use threading, but all underlying data changes in main thread. And I'm always call _adapter.notifyDataSetChanged(); after data has been changed. Please help me! This is my code:

    private class SearchList extends LinkedList<PageInfo>
{
    private static final long serialVersionUID = 1L;

    private PagesListAdapter _adapter;

    public PagesListAdapter getAdapter()
    {
        return _adapter;
    }

    public SearchList(ListView listView)
    {
        super();
        _adapter = new PagesListAdapter(activity, this);
        listView.setAdapter(_adapter);
    }

    private void getSuggestions(final String typedText)
    {
        showProgressVisibility(true);
        new Thread(new Runnable() {

            public void run() {
                android.os.Process.setThreadPriority(android.os.Process.THREAD_PRIORITY_BACKGROUND);
                final String[] sugg = TfdMode.getMode().getSuggestions(typedText);

                activity.runOnUiThread(new Runnable() {
                    public void run() {
                        if (sugg != null)
                        {
                            clear();
                            for (String s: sugg) {
                      开发者_如何学Go          add(new PageInfo(s, PageInfo.PAGE_SUGGESTION, null));
                            }
                        }
                        _adapter.notifyDataSetChanged();
                        showProgressVisibility(false);
                    }
                });
            }
        }).start();
    }

    public void refresh(final String typedText)
    {
        if (typedText.length() >= 3)
        {
            // use suggestions (separate thread)
            getSuggestions(typedText);
        }
        else
        {
            // use recent
            clear();
            for (PageInfo p: TfdMode.getMode().recentManager.pages) {
                if (p.text.startsWith(typedText)) add(p);
            }

            if (size() == 0 && typedText.length() > 0)
                getSuggestions(typedText);  // if no recent - use suggestions
            else
                _adapter.notifyDataSetChanged();
        }

    }


    public class PagesListAdapter extends ArrayAdapter<PageInfo> {

        private LayoutInflater mInflater;

        public PagesListAdapter(Context context, List<PageInfo> objects) {
            super(context, R.layout.bookmarks_item, R.id.bookmark_title, objects);
            mInflater = (LayoutInflater) context.getSystemService(Activity.LAYOUT_INFLATER_SERVICE);
        }

        @Override
        public View getView(int position, View convertView, ViewGroup parent) {   

            final PageInfo b = getItem(position);
            View row = convertView == null ?  mInflater.inflate(R.layout.bookmarks_item, null) : convertView;

            TextView title = (TextView) row.findViewById(R.id.bookmark_title);
            ImageView img = (ImageView) row.findViewById(R.id.bookmark_img);
            ImageView del = (ImageView) row.findViewById(R.id.bookmark_img_del);
            del.setVisibility(View.GONE);

            title.setText(b.text);
            int iconId = b.getIconResId(); 

            if (iconId != -1)
            {
                img.setImageResource(iconId);
                img.setVisibility(View.VISIBLE);
            }
            else
                img.setVisibility(View.INVISIBLE);


            return row;
        }
    }


};

The only place where data is changing - when "refresh" method calls. It always calls from main thread. Why it still happen??? Help!

WHEN EXACTLY java.lang.IllegalStateException EXCEPTION OCCURED? ** **When I expressly run "refresh" method from non-UI thread, I get another exception (CalledFromWrongThreadException) at moment of _adapter.notifyDataSetChanged() call:

10-12 13:20:29.057: ERROR/AndroidRuntime(24746): FATAL EXCEPTION: Thread-27
10-12 13:20:29.057: ERROR/AndroidRuntime(24746): android.view.ViewRoot$CalledFromWrongThreadException: Only the original thread that created a view hierarchy can touch its views.
10-12 13:20:29.057: ERROR/AndroidRuntime(24746):     at android.view.ViewRoot.checkThread(ViewRoot.java:2837)
10-12 13:20:29.057: ERROR/AndroidRuntime(24746):     at android.view.ViewRoot.invalidateChild(ViewRoot.java:619)
10-12 13:20:29.057: ERROR/AndroidRuntime(24746):     at android.view.ViewRoot.invalidateChildInParent(ViewRoot.java:645)
10-12 13:20:29.057: ERROR/AndroidRuntime(24746):     at android.view.ViewGroup.invalidateChild(ViewGroup.java:2505)
10-12 13:20:29.057: ERROR/AndroidRuntime(24746):     at android.view.View.invalidate(View.java:5192)
10-12 13:20:29.057: ERROR/AndroidRuntime(24746):     at android.view.View.setFlags(View.java:4569)
10-12 13:20:29.057: ERROR/AndroidRuntime(24746):     at android.view.View.setVisibility(View.java:3083)
10-12 13:20:29.057: ERROR/AndroidRuntime(24746):     at com.tfd.mobile.TfdSearch.TfdSearch.showProgressVisibility(TfdSearch.java:315)
10-12 13:20:29.057: ERROR/AndroidRuntime(24746):     at com.tfd.mobile.TfdSearch.TfdSearch.access$0(TfdSearch.java:313)
10-12 13:20:29.057: ERROR/AndroidRuntime(24746):     at com.tfd.mobile.TfdSearch.TfdSearch$SearchList.getSuggestions(TfdSearch.java:783)
10-12 13:20:29.057: ERROR/AndroidRuntime(24746):     at com.tfd.mobile.TfdSearch.TfdSearch$SearchList.refresh(TfdSearch.java:823)
10-12 13:20:29.057: ERROR/AndroidRuntime(24746):     at com.tfd.mobile.TfdSearch.TfdSearch$8$1.run(TfdSearch.java:443)
10-12 13:20:29.057: ERROR/AndroidRuntime(24746):     at java.lang.Thread.run(Thread.java:1096)

You have to call refresh from the UI thread which is probably NOT the main thread. You can use this to run something on the UI thread:

Activity.runOnUiThread(Runnable)

-> http://developer.android.com/reference/android/app/Activity.html#runOnUiThread%28java.lang.Runnable%29

_adapter.notifyDataSetChanged();

this have to be executed on the UI thread. Use an handler or runOnUiThread