我正在构建像techcrunch这样的应用程序。我以JSON格式从服务器获取数据，并在列表视图中显示数据，如文章标题，作者姓名和图像。当用户在列表视图中滚动更多文章时，我已经应用了分页方式。我的分页工作正常，但滚动功能存在问题，因为新的或新的数据加载滚动剂量不与数据对齐。为了更清楚地用简单的单词来澄清，当我实际向下滚动时，我的滚动条位于页面顶部，这是我的代码：
public class OneFragment extends Fragment {
public OneFragment(){}
private static final String TAG = OneFragment.class.getSimpleName();
// Movies json url
private static String URL = "http:url&page=1";
private ProgressDialog pDialog;
private List<Movie> movieList = new ArrayList<Movie>();
private ListView listView;
private CustomListAdapter adapter;
int current_page = 1;
int mPreLast;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
final View rootView = inflater.inflate(R.layout.swip, container, false);
pDialog = new ProgressDialog(getActivity());
pDialog.setMessage("Loading...");
pDialog.show();
pDialog.setCancelable(false);
listView = (ListView) rootView.findViewById(R.id.list49);
listView.setOnScrollListener(new AbsListView.OnScrollListener()
{
@Override
public void onScrollStateChanged(AbsListView absListView, int i)
{
}
@Override
public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount)
{
int lastItem = firstVisibleItem + visibleItemCount;
if(lastItem == totalItemCount){
if (mPreLast != lastItem)
{
mPreLast = lastItem;
onStart();
}
}
}
});
listView.setOnItemClickListener(new OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> adapterView, View view, int Position,
long offset) {
// TODO Auto-generated method stub
Movie item = (Movie) adapter.getItem(Position);
Intent intent = new Intent(rootView.getContext(), SingleArticle.class);
single.date = item.getDate();
single.id = item.getId();
startActivity(intent);
}
});
//pDialog = new ProgressDialog(this);
// Showing progress dialog before making http request
return rootView;
}
@Override
public void onStart(){
super.onStart();
// calling adapter changes here, just
// to avoid getactivity()null
// increment current page
current_page += 1;
// Next page request
URL = "http:url&page=" + current_page;
//adapter = new CustomListAdapter(this, movieList);
// changing action bar color
//getActivity().getActionBar().setBackground(
//new ColorDrawable(Color.parseColor("#1b1b1b")));
// Creating volley request obj
JsonArrayRequest movieReq = new JsonArrayRequest(URL,
new Response.Listener<JSONArray>() {
@Override
public void onResponse(JSONArray response) {
Log.d(TAG, response.toString());
hidePDialog();
// Parsing json
for (int i = 0; i < response.length(); i++) {
try {
JSONObject obj = response.getJSONObject(i);
Movie movie = new Movie();
movie.setDate(obj.getString("date"));
movie.setId(obj.getString("id"));
movieList.add(movie);
int currentPosition = listView.getFirstVisiblePosition();
adapter = new CustomListAdapter(getActivity(), movieList);
adapter.notifyDataSetChanged();
listView.setAdapter(adapter);
listView.setSelectionFromTop(currentPosition + 1, 0);
} catch (JSONException e) {
e.printStackTrace();
}
}
}
},new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
VolleyLog.d(TAG, "Error: " + error.getMessage());
new AlertDialog.Builder(getActivity())
.setTitle("No Connectivity ")
.setMessage("Please check your internet connectivity!")
.setPositiveButton(android.R.string.yes, new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
// continue with delete
}
})
//.setNegativeButton(android.R.string.no, new DialogInterface.OnClickListener() {
//public void onClick(DialogInterface dialog, int which) {
// do nothing
//}
//})
.setIcon(android.R.drawable.ic_dialog_alert)
.show();
hidePDialog();
}
});
AppController.getInstance().addToRequestQueue(movieReq);
listView.setAdapter(adapter);
}
private View getActionBar() {
// TODO Auto-generated method stub
return null;
}
@Override
public void onDestroy() {
super.onDestroy();
hidePDialog();
}
private void hidePDialog() {
if (pDialog != null) {
pDialog.dismiss();
pDialog = null;
}
}
}
答案 0 :(得分：0)
你可以尝试这个（我在onStart（）的最后一行添加了一行来设置新的列表位置）
使用此行，您可以设置新位置_
listView.setSelectionFromTop(newPosition, 0);
使用第一个参数设置位置，然后使用第二个参数从列表顶部设置distnace
@Override
public void onStart(){
super.onStart();
// calling adapter changes here, just
// to avoid getactivity()null
// increment current page
current_page += 1;
// Next page request
URL = "http:url&page=" + current_page;
//adapter = new CustomListAdapter(this, movieList);
// changing action bar color
//getActivity().getActionBar().setBackground(
//new ColorDrawable(Color.parseColor("#1b1b1b")));
// Creating volley request obj
JsonArrayRequest movieReq = new JsonArrayRequest(URL,
new Response.Listener<JSONArray>() {
@Override
public void onResponse(JSONArray response) {
Log.d(TAG, response.toString());
hidePDialog();
// Parsing json
for (int i = 0; i < response.length(); i++) {
try {
JSONObject obj = response.getJSONObject(i);
Movie movie = new Movie();
movie.setDate(obj.getString("date"));
movie.setId(obj.getString("id"));
movieList.add(movie);
int currentPosition = listView.getFirstVisiblePosition();
adapter = new CustomListAdapter(getActivity(), movieList);
adapter.notifyDataSetChanged();
listView.setAdapter(adapter);
listView.setSelectionFromTop(currentPosition + 1, 0);
} catch (JSONException e) {
e.printStackTrace();
}
}
}
},new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
VolleyLog.d(TAG, "Error: " + error.getMessage());
new AlertDialog.Builder(getActivity())
.setTitle("No Connectivity ")
.setMessage("Please check your internet connectivity!")
.setPositiveButton(android.R.string.yes, new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
// continue with delete
}
})
//.setNegativeButton(android.R.string.no, new DialogInterface.OnClickListener() {
//public void onClick(DialogInterface dialog, int which) {
// do nothing
//}
//})
.setIcon(android.R.drawable.ic_dialog_alert)
.show();
hidePDialog();
}
});
AppController.getInstance().addToRequestQueue(movieReq);
listView.setAdapter(adapter);
//Set the new position
listView.setSelectionFromTop(currentPosition + 1, 0);
}