我的列表中有重复项目有问题。我想从我的数据库中查看我的项目。如果你愿意，在列表的顶部，有数据库中的最后一项，如果你向下滚动，你会看到历史（数据库的其余元素），但我不知道为什么......我有重复的项目这里。有人可以帮帮我吗？
代码：
/**
* A fragment representing a list of Items.
* <p/>
* Large screen devices (such as tablets) are supported by replacing the ListView
* with a GridView.
* <p/>
* Activities containing this fragment MUST implement the {@link OnFragmentInteractionListener}
* interface.
*/
public class PlacesFragment extends Fragment implements AbsListView.OnItemClickListener {
// TODO: Rename parameter arguments, choose names that match
// the fragment initialization parameters, e.g. ARG_ITEM_NUMBER
private static final String ARG_PARAM1 = "param1";
private static final String ARG_PARAM2 = "param2";
public static final int PAGE_SIZE = 5;
public static final int LIST_INIT_SIZE = 1;
ImageView imageView;
String[] test;
String text = "Central Park";
Date data = new Date();
String data_database = String.valueOf(data);
// TODO: Rename and change types of parameters
private String mParam1;
private String mParam2;
private OnFragmentInteractionListener mListener;
final List<PlaceListItem> items = new ArrayList<>();
/**
* The fragment's ListView/GridView.
*/
private AbsListView mListView;
/**
* The Adapter which will be used to populate the ListView/GridView with
* Views.
*/
private ListAdapter mAdapter;
/**
* Mandatory empty constructor for the fragment manager to instantiate the
* fragment (e.g. upon screen orientation changes).
*/
public PlacesFragment() {
}
// TODO: Rename and change types of parameters
public static PlacesFragment newInstance(String param1, String param2) {
PlacesFragment fragment = new PlacesFragment();
Bundle args = new Bundle();
args.putString(ARG_PARAM1, param1);
args.putString(ARG_PARAM2, param2);
fragment.setArguments(args);
return fragment;
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
if (getArguments() != null) {
mParam1 = getArguments().getString(ARG_PARAM1);
mParam2 = getArguments().getString(ARG_PARAM2);
}
// TODO: Change Adapter to display your content
// mAdapter = new ArrayAdapter<>(getActivity(), android.R.layout.simple_list_item_1, android.R.id.text1, DummyContent.ITEMS);
}
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
final View view = inflater.inflate(R.layout.fragment_place, container, false);
Context ctx = view.getContext();
final DataBase dataBase = new DataBase(getActivity().getApplicationContext());
SQLiteDatabase db = dataBase.getReadableDatabase();
Cursor cr = dataBase.getInformation(dataBase);
cr.moveToFirst();
// if (!db.isOpen()) {
// dataBase.onCreate(db);
// }
// dataBase.onCreate(db);
//ctx.deleteDatabase(DataBase.TABLE_NAME);
final DetectionLocation detectionLocation = new DetectionLocation(ctx);
SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(ctx);
Integer val = Integer.valueOf(prefs.getString("sync_frequency", ""));
final String sync_status = String.valueOf(val);
dataBase.insertInformation(dataBase, "Guid", String.valueOf(detectionLocation.getLongitude()), String.valueOf(detectionLocation.getLatitude()), "N", data, sync_status);
mListView = (AbsListView) view.findViewById(android.R.id.list);
for (int i = 0; i < LIST_INIT_SIZE; i++) {
items.add(new PlaceListItem(cr.getString(4), cr.getString(1), cr.getString(2)));
cr.moveToNext();
}
final CustomListAdapter adapter = new CustomListAdapter(getActivity(), items);
// dataBase.insertInformation(dataBase, "Guid", String.valueOf(detectionLocation.getLongitude()), String.valueOf(detectionLocation.getLatitude()), "N", data, sync_status);
EndlessScrollListener scroll = new EndlessScrollListener(PAGE_SIZE) {
Cursor cr = dataBase.getInformation(dataBase);
@Override
public void onLoadMore(int page, int totalItemsCount) {
cr.moveToFirst();
// dataBase.insertInformation(dataBase, "Guid", String.valueOf(detectionLocation.getLongitude()), String.valueOf(detectionLocation.getLatitude()), "N", data, sync_status);
for (int i = 0; i < totalItemsCount; i++) {
if (cr.isLast()) {
break;
}
items.add(new PlaceListItem(cr.getString(4), cr.getString(1), cr.getString(2)));
// adapter.add(new PlaceListItem(cr.getString(4), cr.getString(1), cr.getString(2)));
adapter.add(items.get(i));
cr.moveToNext();
}
adapter.notifyDataSetChanged();
}
};
// mListView.setOnScrollListener(scroll);
// mListView.setAdapter(adapter);
Timer timer = new Timer();
timer.schedule(new TimerTask() {
@Override
public void run() {
getActivity().runOnUiThread(new Runnable() {
@Override
public void run() {
Cursor cr = dataBase.getInformation(dataBase);
cr.moveToFirst();
if (!data.toString().equals(cr.getString(4))) {
dataBase.insertInformation(dataBase, "Guid", String.valueOf(detectionLocation.getLongitude()), String.valueOf(detectionLocation.getLatitude()), "N", data, sync_status);
}
// TODO get newest entries and append on list
//items.add(new PlaceListItem(cr.getString(4), cr.getString(1), cr.getString(2)));
adapter.insert(new PlaceListItem(cr.getString(4), cr.getString(1), cr.getString(2)), 0);//
adapter.notifyDataSetChanged();
// mListView.invalidateViews();
}
});
}
}, 2/*val*/);
mListView.setOnScrollListener(scroll);
mListView.setAdapter(adapter);
mListView.setOnItemClickListener(this);
return view;
}
@Override
public void onAttach(Activity activity) {
super.onAttach(activity);
}
@Override
public void onDetach() {
super.onDetach();
mListener = null;
}
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
if (null != mListener) {
// Notify the active callbacks interface (the activity, if the
// fragment is attached to one) that an item has been selected.
mListener.onFragmentInteraction(DummyContent.ITEMS.get(position).id);
}
}
/**
* The default content for this Fragment has a TextView that is shown when
* the list is empty. If you would like to change the text, call this method
* to supply the text it should use.
*/
public void setEmptyText(CharSequence emptyText) {
View emptyView = mListView.getEmptyView();
if (emptyView instanceof TextView) {
((TextView) emptyView).setText(emptyText);
}
}
/**
* This interface must be implemented by activities that contain this
* fragment to allow an interaction in this fragment to be communicated
* to the activity and potentially other fragments contained in that
* activity.
* <p/>
* See the Android Training lesson <a href=
* "http://developer.android.com/training/basics/fragments/communicating.html"
* >Communicating with Other Fragments</a> for more information.
*/
public interface OnFragmentInteractionListener {
// TODO: Update argument type and name
public void onFragmentInteraction(String id);
}
}
您可以在下图中看到有重复的项目（仅查看日期）。链接：http://i.stack.imgur.com/thN1Z.png
答案 0 :(得分：0)
我已经解决了这个问题，在一个集合中传递数据，自动删除重复项。
LinkedHashSet<String> hs = new LinkedHashSet();
hs.addAll(items);
items.clear();
items.addAll(hs);