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      1 /*
      2  * Copyright (C) 2010 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 package com.example.android.supportv4.app;
     18 
     19 import android.database.Cursor;
     20 import android.net.Uri;
     21 import android.os.Bundle;
     22 import android.provider.Contacts.People;
     23 import android.text.TextUtils;
     24 import android.util.Log;
     25 import android.view.Menu;
     26 import android.view.MenuInflater;
     27 import android.view.MenuItem;
     28 import android.view.View;
     29 import android.widget.ListView;
     30 import android.widget.SearchView;
     31 
     32 import androidx.annotation.NonNull;
     33 import androidx.cursoradapter.widget.SimpleCursorAdapter;
     34 import androidx.fragment.app.FragmentActivity;
     35 import androidx.fragment.app.FragmentManager;
     36 import androidx.fragment.app.ListFragment;
     37 import androidx.loader.app.LoaderManager;
     38 import androidx.loader.content.CursorLoader;
     39 import androidx.loader.content.Loader;
     40 
     41 /**
     42  * Demonstration of the use of a CursorLoader to load and display contacts
     43  * data in a fragment.
     44  */
     45 @SuppressWarnings("all")
     46 public class LoaderCursorSupport extends FragmentActivity {
     47 
     48     @Override
     49     protected void onCreate(Bundle savedInstanceState) {
     50         super.onCreate(savedInstanceState);
     51 
     52         FragmentManager fm = getSupportFragmentManager();
     53 
     54         // Create the list fragment and add it as our sole content.
     55         if (fm.findFragmentById(android.R.id.content) == null) {
     56             CursorLoaderListFragment list = new CursorLoaderListFragment();
     57             fm.beginTransaction().add(android.R.id.content, list).commit();
     58         }
     59     }
     60 
     61 //BEGIN_INCLUDE(fragment_cursor)
     62     public static class CursorLoaderListFragment extends ListFragment
     63             implements LoaderManager.LoaderCallbacks<Cursor> {
     64 
     65         // This is the Adapter being used to display the list's data.
     66         SimpleCursorAdapter mAdapter;
     67 
     68         // If non-null, this is the current filter the user has provided.
     69         String mCurFilter;
     70 
     71         @Override public void onActivityCreated(Bundle savedInstanceState) {
     72             super.onActivityCreated(savedInstanceState);
     73 
     74             // Give some text to display if there is no data.  In a real
     75             // application this would come from a resource.
     76             setEmptyText("No phone numbers");
     77 
     78             // We have a menu item to show in action bar.
     79             setHasOptionsMenu(true);
     80 
     81             // Create an empty adapter we will use to display the loaded data.
     82             mAdapter = new SimpleCursorAdapter(getActivity(),
     83                     android.R.layout.simple_list_item_1, null,
     84                     new String[] { People.DISPLAY_NAME },
     85                     new int[] { android.R.id.text1}, 0);
     86             setListAdapter(mAdapter);
     87 
     88             // Start out with a progress indicator.
     89             setListShown(false);
     90 
     91             // Prepare the loader.  Either re-connect with an existing one,
     92             // or start a new one.
     93             getLoaderManager().initLoader(0, null, this);
     94         }
     95 
     96         @Override public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
     97             // Place an action bar item for searching.
     98             MenuItem item = menu.add("Search");
     99             item.setIcon(android.R.drawable.ic_menu_search);
    100             item.setShowAsAction(MenuItem.SHOW_AS_ACTION_ALWAYS
    101                     | MenuItem.SHOW_AS_ACTION_COLLAPSE_ACTION_VIEW);
    102             final SearchView searchView = new SearchView(getActivity());
    103             searchView.setOnQueryTextListener(new SearchView.OnQueryTextListener() {
    104                 @Override
    105                 public boolean onQueryTextChange(String newText) {
    106                     // Called when the action bar search text has changed.  Update
    107                     // the search filter, and restart the loader to do a new query
    108                     // with this filter.
    109                     String newFilter = !TextUtils.isEmpty(newText) ? newText : null;
    110                     // Don't do anything if the filter hasn't actually changed.
    111                     // Prevents restarting the loader when restoring state.
    112                     if (mCurFilter == null && newFilter == null) {
    113                         return true;
    114                     }
    115                     if (mCurFilter != null && mCurFilter.equals(newFilter)) {
    116                         return true;
    117                     }
    118                     mCurFilter = newFilter;
    119                     getLoaderManager().restartLoader(0, null, CursorLoaderListFragment.this);
    120                     return true;
    121                 }
    122 
    123                 @Override
    124                 public boolean onQueryTextSubmit(String s) {
    125                     return false;
    126                 }
    127             });
    128             searchView.setOnCloseListener(new SearchView.OnCloseListener() {
    129                 @Override
    130                 public boolean onClose() {
    131                     if (!TextUtils.isEmpty(searchView.getQuery())) {
    132                         searchView.setQuery(null, true);
    133                     }
    134                     return true;
    135                 }
    136             });
    137             item.setActionView(searchView);
    138         }
    139 
    140         @Override public void onListItemClick(ListView l, View v, int position, long id) {
    141             // Insert desired behavior here.
    142             Log.i("FragmentComplexList", "Item clicked: " + id);
    143         }
    144 
    145         // These are the Contacts rows that we will retrieve.
    146         static final String[] CONTACTS_SUMMARY_PROJECTION = new String[] {
    147             People._ID,
    148             People.DISPLAY_NAME,
    149         };
    150 
    151         @NonNull
    152         public Loader<Cursor> onCreateLoader(int id, Bundle args) {
    153             // This is called when a new Loader needs to be created.  This
    154             // sample only has one Loader, so we don't care about the ID.
    155             // First, pick the base URI to use depending on whether we are
    156             // currently filtering.
    157             Uri baseUri;
    158             if (mCurFilter != null) {
    159                 baseUri = Uri.withAppendedPath(People.CONTENT_FILTER_URI, Uri.encode(mCurFilter));
    160             } else {
    161                 baseUri = People.CONTENT_URI;
    162             }
    163 
    164             // Now create and return a CursorLoader that will take care of
    165             // creating a Cursor for the data being displayed.
    166             String select = "((" + People.DISPLAY_NAME + " NOTNULL) AND ("
    167                     + People.DISPLAY_NAME + " != '' ))";
    168             return new CursorLoader(getActivity(), baseUri,
    169                     CONTACTS_SUMMARY_PROJECTION, select, null,
    170                     People.DISPLAY_NAME + " COLLATE LOCALIZED ASC");
    171         }
    172 
    173         public void onLoadFinished(@NonNull Loader<Cursor> loader, Cursor data) {
    174             // Swap the new cursor in.  (The framework will take care of closing the
    175             // old cursor once we return.)
    176             mAdapter.swapCursor(data);
    177 
    178             // The list should now be shown.
    179             if (isResumed()) {
    180                 setListShown(true);
    181             } else {
    182                 setListShownNoAnimation(true);
    183             }
    184         }
    185 
    186         public void onLoaderReset(@NonNull Loader<Cursor> loader) {
    187             // This is called when the last Cursor provided to onLoadFinished()
    188             // above is about to be closed.  We need to make sure we are no
    189             // longer using it.
    190             mAdapter.swapCursor(null);
    191         }
    192     }
    193 //END_INCLUDE(fragment_cursor)
    194 }
    195