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.cursoradapter.widget.SimpleCursorAdapter; 33 import androidx.fragment.app.FragmentActivity; 34 import androidx.fragment.app.FragmentManager; 35 import androidx.fragment.app.ListFragment; 36 import androidx.loader.app.LoaderManager; 37 import androidx.loader.content.CursorLoader; 38 import androidx.loader.content.Loader; 39 40 import org.jspecify.annotations.NonNull; 41 import org.jspecify.annotations.Nullable; 42 43 /** 44 * Demonstration of the use of a CursorLoader to load and display contacts 45 * data in a fragment. 46 */ 47 @SuppressWarnings("all") 48 public class LoaderCursorSupport extends FragmentActivity { 49 50 @Override onCreate(Bundle savedInstanceState)51 protected void onCreate(Bundle savedInstanceState) { 52 super.onCreate(savedInstanceState); 53 54 FragmentManager fm = getSupportFragmentManager(); 55 56 // Create the list fragment and add it as our sole content. 57 if (fm.findFragmentById(android.R.id.content) == null) { 58 CursorLoaderListFragment list = new CursorLoaderListFragment(); 59 fm.beginTransaction().add(android.R.id.content, list).commit(); 60 } 61 } 62 63 //BEGIN_INCLUDE(fragment_cursor) 64 public static class CursorLoaderListFragment extends ListFragment 65 implements LoaderManager.LoaderCallbacks<Cursor> { 66 67 // This is the Adapter being used to display the list's data. 68 SimpleCursorAdapter mAdapter; 69 70 // If non-null, this is the current filter the user has provided. 71 String mCurFilter; 72 73 @Override onViewCreated(@onNull View view, @Nullable Bundle savedInstanceState)74 public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) { 75 super.onViewCreated(view, savedInstanceState); 76 77 // Give some text to display if there is no data. In a real 78 // application this would come from a resource. 79 setEmptyText("No phone numbers"); 80 81 // We have a menu item to show in action bar. 82 setHasOptionsMenu(true); 83 84 // Create an empty adapter we will use to display the loaded data. 85 mAdapter = new SimpleCursorAdapter(getActivity(), 86 android.R.layout.simple_list_item_1, null, 87 new String[] { People.DISPLAY_NAME }, 88 new int[] { android.R.id.text1}, 0); 89 setListAdapter(mAdapter); 90 91 // Start out with a progress indicator. 92 setListShown(false); 93 94 // Prepare the loader. Either re-connect with an existing one, 95 // or start a new one. 96 getLoaderManager().initLoader(0, null, this); 97 } 98 onCreateOptionsMenu(Menu menu, MenuInflater inflater)99 @Override public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) { 100 // Place an action bar item for searching. 101 MenuItem item = menu.add("Search"); 102 item.setIcon(android.R.drawable.ic_menu_search); 103 item.setShowAsAction(MenuItem.SHOW_AS_ACTION_ALWAYS 104 | MenuItem.SHOW_AS_ACTION_COLLAPSE_ACTION_VIEW); 105 final SearchView searchView = new SearchView(getActivity()); 106 searchView.setOnQueryTextListener(new SearchView.OnQueryTextListener() { 107 @Override 108 public boolean onQueryTextChange(String newText) { 109 // Called when the action bar search text has changed. Update 110 // the search filter, and restart the loader to do a new query 111 // with this filter. 112 String newFilter = !TextUtils.isEmpty(newText) ? newText : null; 113 // Don't do anything if the filter hasn't actually changed. 114 // Prevents restarting the loader when restoring state. 115 if (mCurFilter == null && newFilter == null) { 116 return true; 117 } 118 if (mCurFilter != null && mCurFilter.equals(newFilter)) { 119 return true; 120 } 121 mCurFilter = newFilter; 122 getLoaderManager().restartLoader(0, null, CursorLoaderListFragment.this); 123 return true; 124 } 125 126 @Override 127 public boolean onQueryTextSubmit(String s) { 128 return false; 129 } 130 }); 131 searchView.setOnCloseListener(new SearchView.OnCloseListener() { 132 @Override 133 public boolean onClose() { 134 if (!TextUtils.isEmpty(searchView.getQuery())) { 135 searchView.setQuery(null, true); 136 } 137 return true; 138 } 139 }); 140 item.setActionView(searchView); 141 } 142 onListItemClick(ListView l, View v, int position, long id)143 @Override public void onListItemClick(ListView l, View v, int position, long id) { 144 // Insert desired behavior here. 145 Log.i("FragmentComplexList", "Item clicked: " + id); 146 } 147 148 // These are the Contacts rows that we will retrieve. 149 static final String[] CONTACTS_SUMMARY_PROJECTION = new String[] { 150 People._ID, 151 People.DISPLAY_NAME, 152 }; 153 154 @NonNull 155 @Override onCreateLoader(int id, Bundle args)156 public Loader<Cursor> onCreateLoader(int id, Bundle args) { 157 // This is called when a new Loader needs to be created. This 158 // sample only has one Loader, so we don't care about the ID. 159 // First, pick the base URI to use depending on whether we are 160 // currently filtering. 161 Uri baseUri; 162 if (mCurFilter != null) { 163 baseUri = Uri.withAppendedPath(People.CONTENT_FILTER_URI, Uri.encode(mCurFilter)); 164 } else { 165 baseUri = People.CONTENT_URI; 166 } 167 168 // Now create and return a CursorLoader that will take care of 169 // creating a Cursor for the data being displayed. 170 String select = "((" + People.DISPLAY_NAME + " NOTNULL) AND (" 171 + People.DISPLAY_NAME + " != '' ))"; 172 return new CursorLoader(getActivity(), baseUri, 173 CONTACTS_SUMMARY_PROJECTION, select, null, 174 People.DISPLAY_NAME + " COLLATE LOCALIZED ASC"); 175 } 176 177 @Override onLoadFinished(@onNull Loader<Cursor> loader, Cursor data)178 public void onLoadFinished(@NonNull Loader<Cursor> loader, Cursor data) { 179 // Swap the new cursor in. (The framework will take care of closing the 180 // old cursor once we return.) 181 mAdapter.swapCursor(data); 182 183 // The list should now be shown. 184 if (isResumed()) { 185 setListShown(true); 186 } else { 187 setListShownNoAnimation(true); 188 } 189 } 190 191 @Override onLoaderReset(@onNull Loader<Cursor> loader)192 public void onLoaderReset(@NonNull Loader<Cursor> loader) { 193 // This is called when the last Cursor provided to onLoadFinished() 194 // above is about to be closed. We need to make sure we are no 195 // longer using it. 196 mAdapter.swapCursor(null); 197 } 198 } 199 //END_INCLUDE(fragment_cursor) 200 } 201