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POListview populates, but the adapter claims to be empty
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copied!<p>So I'm developing an app over the summer. It stores items in the database, displays them in a listview (otherwise makes Toast telling the user its empty), and allows users to see details by clicking on one. Eventually I plan on having search criteria narrow down the list, but I'm not there yet.</p> <p>My problem is that the listview seems to be populating, but the app makes Toast....</p> <p>ResultsActivity.java</p> <pre><code>public class ResultsActivity extends FragmentActivity implements ResultsFragment.OnPlantSelectedListener { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.fragment_results); }// method: FragmentActivity.onCreate() @Override public boolean onCreateOptionsMenu(Menu menu) { getMenuInflater().inflate(R.menu.results, menu); return true; }// method: FragmentActivity.onCreateOptionsMenu() /* Custom methods */ //@Override public void onPlantSelected(long id){ Intent intent = new Intent(this, PlantViewActivity.class); //TODO confirm id intent.putExtra(DBContentProvider.KEY_PLANT_ID, id); startActivity(intent); }// method: ResultsFragment.OnPlantSelectedListener.onPlantSelected(long) }// class: ResultsActivity extends ListActivity </code></pre> <p>ResultsFragment.java</p> <pre><code>public class ResultsFragment extends ListFragment implements LoaderManager.LoaderCallbacks<Cursor>{ private static OnPlantSelectedListener emptyPlantSelectedListener = new OnPlantSelectedListener(){ @Override public void onPlantSelected(long id){} }; private static OnPlantSelectedListener plantSelectedListener = emptyPlantSelectedListener; private static final String STATE_ACTIVATED_POSITION = "activated_position"; private int activatedPosition = ListView.INVALID_POSITION; private SimpleCursorAdapter adapter; public ResultsFragment(){} /* Fragment Lifespan */ @Override public void onCreate(Bundle savedInstanceState){ super.onCreate(savedInstanceState); String[] dbPlantColumns = {DBContentProvider.KEY_GENUS_TEXT, DBContentProvider.KEY_SPECIES, DBContentProvider.KEY_COMMON_NAME_GROUP}; int[] fragPlantFields = {R.id.result_item_txt_genus, R.id.result_item_txt_species, R.id.result_item_txt_common_name}; getLoaderManager().initLoader(0x01, null, this);//null can be replaced by a Bundle of search criteria adapter = new SimpleCursorAdapter(getActivity().getApplicationContext(), R.layout.list_item_results, null, dbPlantColumns, fragPlantFields, CursorAdapter.FLAG_REGISTER_CONTENT_OBSERVER); setListAdapter(adapter); if(adapter.isEmpty())//This returns true Toast.makeText(getActivity().getApplicationContext(), "Nothing returned from the database", Toast.LENGTH_LONG).show(); }// method: Activity.onCreate(Bundle) @Override public void onViewCreated(View view, Bundle savedInstanceState){ super.onViewCreated(view, savedInstanceState); if (savedInstanceState != null && savedInstanceState.containsKey(STATE_ACTIVATED_POSITION)){ setActivatedPosition(savedInstanceState.getInt(STATE_ACTIVATED_POSITION)); } }// method: ListFragment.onViewCreated(View, Bundle) @Override public void onAttach(Activity activity){ super.onAttach(activity); if (!(activity instanceof OnPlantSelectedListener)){ throw new IllegalStateException("Activity must implement fragment's listener."); } plantSelectedListener = (OnPlantSelectedListener) activity; }// method: ListFragment.onAttach(Activity) @Override public void onDetach(){ super.onDetach(); plantSelectedListener = emptyPlantSelectedListener; }// method: ListFragment.onDetach() @Override public void onSaveInstanceState(Bundle outState){ super.onSaveInstanceState(outState); if (activatedPosition != ListView.INVALID_POSITION){ outState.putInt(STATE_ACTIVATED_POSITION, activatedPosition); } }// method: ListFragment.onSaveInstanceState(Bundle) /* LoaderManager abstract methods */ @Override public Loader<Cursor> onCreateLoader(int id, Bundle args){ //TODO parse args for searching. Second null is String[]; index 0-17 are search arguments. String[] arguments = new String[18]; String[] dbPlantColumns = {DBContentProvider.TABLE_PLANT + "." + DBContentProvider.KEY_PLANT_ID, DBContentProvider.KEY_FAMILY_TEXT, DBContentProvider.KEY_GENUS_TEXT, DBContentProvider.KEY_SPECIES, DBContentProvider.KEY_COMMON_NAME_GROUP, DBContentProvider.KEY_GROWTH_FORM_TEXT}; CursorLoader cursorLoader = new CursorLoader(getActivity(), Uri.parse(DBContentProvider.CONTENT_URI_STRING + "search"), dbPlantColumns, null, arguments, null); return cursorLoader; }// method: LoaderCallbacks.onCreateLoader(int, Bundle) @Override public void onLoadFinished(Loader<Cursor> loader, Cursor cursor){ adapter.swapCursor(cursor); }// method: LoaderCallbacks.onLoadFinished(Loader<Cursor>, Cursor) @Override public void onLoaderReset(Loader<Cursor> loader){ adapter.swapCursor(null); }// method: LoaderCallbacks.onLoaderReset(Loader<Cursor>) /* ListFragment response methods */ @Override public void onListItemClick(ListView listView, View view, int position, long id){ super.onListItemClick(listView, view, position, id); plantSelectedListener.onPlantSelected(id /*Get id of plant at this position*/); }// method: ListFragment.onListItemClick(Listview, View, int, long) public void setActivateOnItemClick(boolean activateOnItemClick){ getListView().setChoiceMode(ListView.CHOICE_MODE_SINGLE); }// method: setActivateOnItemClick(boolean) private void setActivatedPosition(int position){ if(position == ListView.INVALID_POSITION){ getListView().setItemChecked(activatedPosition, false); } else{ getListView().setItemChecked(position, true); } activatedPosition = position; }//method: setActiviatedPosition(int) /** * OnPlantSelectedListener is used by the fragment and the activity to * make sure that the selection of a plant is dealt with correctly. */ public interface OnPlantSelectedListener{ public void onPlantSelected(long id); }// interface: OnPlantSelectedListener }// class: ResultsFragment extends ListFragment </code></pre> <p>activity_results.xml</p> <pre><code><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" tools:context=".ResultsActivity" android:id="@+id/Results_Lin" android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical">  <ListView android:id="@android:id/list" android:layout_width="match_parent" android:layout_height="match_parent" android:padding="5dp"> </ListView> <TextView android:id="@+id/results_empty" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="@string/txt_no_results"/> </LinearLayout> </code></pre> <p>fragment_results.xml</p> <pre><code><?xml version="1.0" encoding="utf-8"?> <fragment xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent" android:name="edu.dordt.grassrootsplantid.ResultsFragment" android:id="@+id/Result_Fragment"/> </code></pre> <p>list_item_results.xml</p> <pre><code><RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:id="@+id/Result_Item_Lin" android:layout_width="match_parent" android:layout_height="match_parent" android:padding="5dp"> <TextView android:id="@+id/result_item_txt_lbl_common_name" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="@string/lbl_common_name"/> <TextView android:id="@+id/result_item_txt_common_name" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_toRightOf="@id/result_item_txt_lbl_common_name"/> <TextView android:id="@+id/result_item_txt_lbl_scientific_name" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_below="@id/result_item_txt_lbl_common_name" android:text="@string/lbl_scientific_name"/> <TextView android:id="@+id/result_item_txt_genus" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_toRightOf="@id/result_item_txt_lbl_scientific_name" android:layout_below="@id/result_item_txt_lbl_common_name"/> <TextView android:id="@+id/result_item_txt_species" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_toRightOf="@id/result_item_txt_genus" android:layout_below="@id/result_item_txt_lbl_common_name" android:layout_marginLeft="5dp"/> </RelativeLayout> </code></pre> <p>I probably misunderstand how to use fragments, but it was necessary in order to use the tutorial I was following for using Content Providers. I didn't put in the Content Provider here, but I'm pretty sure that's working (well...broken somewhere else, but I think I can handle that one). If someone wants to see it anyway, I can edit my question.</p> <p>If it's at all relevant, the list items have their data and are clickable, but they appear greyed out as though they are unclickable. Perhaps that's a styling issue, but I would figure they would use the style shared by the rest of the app.</p> <p>But to reiterate my problem, the listview is populating, but the adapter claims to be empty. I'm not sure how big of an issue it is/will be, but I would like either a way to get them to agree or an explanation of why they might not need to.</p>

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