我正在使用带有gridview的viewpager并将json数据下载到其中并实现了gridview滚动侦听器，但每当我再次启动活动时，实现sroll侦听器的当前viewpager片段显示为空白。 这是我的代码，请看看并告诉我我的错误。
//My Activity Fragment
private static String url = "http://--------/------";
private int mVisibleThreshold = 5;
private int mCurrentPage = 0;
private int mPreviousTotal = 0;
private boolean mLoading = true;
private boolean mLastPage = false;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.gridview_fragment, container,
false);
setRetainInstance(true);
arrayList = new ArrayList<Items>();
gridView = (GridView) rootView.findViewById(R.id.gridView1);
//My Json Execution
new LoadData().execute(url);
//Scroll listener when gridview reaches at end
gridView.setOnScrollListener(new OnScrollListener() {
@Override
public void onScroll(AbsListView view, int firstVisibleItem,
int visibleItemCount, int totalItemCount) {
if (mLoading) {
if (totalItemCount > mPreviousTotal) {
mLoading = false;
mPreviousTotal = totalItemCount;
mCurrentPage++;
if (mCurrentPage + 1 > 10) {
mLastPage = true;
}
}
}
if (!mLastPage
&& !mLoading
&& (totalItemCount - visibleItemCount) <= (firstVisibleItem + mVisibleThreshold)) {
//Loading new datas in gridview
new LoadData()
.execute("http://-----/-----");
mLoading = true;
}
}
});
return rootView;
}
private class LoadData extends AsyncTask<String, Void, Void> {
@Override
protected void onPostExecute(Void result) {
//checking whether adapter is null or not
if (adap == null) {
adap = new Grid_View_Adatper(getActivity()
.getApplicationContext(), arrayList);
gridView.setAdapter(adap);
}
adap.notifyDataSetChanged();
super.onPostExecute(result);
}
@Override
protected Void doInBackground(String... urls) {
try {
HttpClient client = new DefaultHttpClient();
HttpGet httpget = new HttpGet(urls[0]);
HttpResponse response = client.execute(httpget);
HttpEntity entity = response.getEntity();
String data = EntityUtils.toString(entity);
JSONArray json = new JSONArray(data);
for (int i = 0; i < json.length(); i++) {
JSONObject e = json.getJSONObject(i);
String name = e.getString("name");
String price = e.getString("price");
String image = e.getString("image");
String code = e.getString("sku");
tems = new Items(name, price, image, code);
arrayList.add(tems);
}
} catch (JSONException e) {
e.printStackTrace();
} catch (ClientProtocolException e) {
} catch (IOException e) {
} catch (RuntimeException e) {
}
return null;
}
}
}
提前致谢...