LoaderRetainedSupport.java revision 458543f38db49fdcb1764f007ded33820964c3fe
1/* 2 * Copyright (C) 2012 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 17package com.example.android.supportv4.app; 18 19import android.database.Cursor; 20import android.net.Uri; 21import android.os.Bundle; 22import android.provider.Contacts.People; 23import android.support.v4.app.FragmentActivity; 24import android.support.v4.app.FragmentManager; 25import android.support.v4.app.ListFragment; 26import android.support.v4.app.LoaderManager; 27import android.support.v4.content.CursorLoader; 28import android.support.v4.content.Loader; 29import android.support.v4.widget.SimpleCursorAdapter; 30import android.text.TextUtils; 31import android.util.Log; 32import android.view.Menu; 33import android.view.MenuInflater; 34import android.view.MenuItem; 35import android.view.View; 36import android.widget.ListView; 37import android.widget.SearchView; 38 39/** 40 * Demonstration of the use of a CursorLoader to load and display contacts 41 * data in a fragment. 42 */ 43@SuppressWarnings("all") 44public class LoaderRetainedSupport extends FragmentActivity { 45 46 @Override 47 protected void onCreate(Bundle savedInstanceState) { 48 super.onCreate(savedInstanceState); 49 50 FragmentManager fm = getSupportFragmentManager(); 51 52 // Create the list fragment and add it as our sole content. 53 if (fm.findFragmentById(android.R.id.content) == null) { 54 CursorLoaderListFragment list = new CursorLoaderListFragment(); 55 fm.beginTransaction().add(android.R.id.content, list).commit(); 56 } 57 } 58 59//BEGIN_INCLUDE(fragment_cursor) 60 public static class CursorLoaderListFragment extends ListFragment 61 implements LoaderManager.LoaderCallbacks<Cursor> { 62 63 // This is the Adapter being used to display the list's data. 64 SimpleCursorAdapter mAdapter; 65 66 // If non-null, this is the current filter the user has provided. 67 String mCurFilter; 68 69 @Override public void onActivityCreated(Bundle savedInstanceState) { 70 super.onActivityCreated(savedInstanceState); 71 72 // In this sample we are going to use a retained fragment. 73 setRetainInstance(true); 74 75 // Give some text to display if there is no data. In a real 76 // application this would come from a resource. 77 setEmptyText("No phone numbers"); 78 79 // We have a menu item to show in action bar. 80 setHasOptionsMenu(true); 81 82 // Create an empty adapter we will use to display the loaded data. 83 mAdapter = new SimpleCursorAdapter(getActivity(), 84 android.R.layout.simple_list_item_1, null, 85 new String[] { People.DISPLAY_NAME }, 86 new int[] { android.R.id.text1}, 0); 87 setListAdapter(mAdapter); 88 89 // Start out with a progress indicator. 90 setListShown(false); 91 92 // Prepare the loader. Either re-connect with an existing one, 93 // or start a new one. 94 getLoaderManager().initLoader(0, null, this); 95 } 96 97 @Override public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) { 98 // Place an action bar item for searching. 99 MenuItem item = menu.add("Search"); 100 item.setIcon(android.R.drawable.ic_menu_search); 101 item.setShowAsAction(MenuItem.SHOW_AS_ACTION_ALWAYS 102 | MenuItem.SHOW_AS_ACTION_COLLAPSE_ACTION_VIEW); 103 SearchView searchView = new SearchView(getActivity()); 104 searchView.setOnQueryTextListener(new SearchView.OnQueryTextListener() { 105 @Override 106 public boolean onQueryTextChange(String newText) { 107 // Called when the action bar search text has changed. Update 108 // the search filter, and restart the loader to do a new query 109 // with this filter. 110 String newFilter = !TextUtils.isEmpty(newText) ? newText : null; 111 // Don't do anything if the filter hasn't actually changed. 112 // Prevents restarting the loader when restoring state. 113 if (mCurFilter == null && newFilter == null) { 114 return true; 115 } 116 if (mCurFilter != null && mCurFilter.equals(newFilter)) { 117 return true; 118 } 119 mCurFilter = newFilter; 120 getLoaderManager().restartLoader(0, null, CursorLoaderListFragment.this); 121 return true; 122 } 123 124 @Override 125 public boolean onQueryTextSubmit(String s) { 126 return false; 127 } 128 }); 129 item.setActionView(searchView); 130 } 131 132 @Override public void onListItemClick(ListView l, View v, int position, long id) { 133 // Insert desired behavior here. 134 Log.i("FragmentComplexList", "Item clicked: " + id); 135 } 136 137 // These are the Contacts rows that we will retrieve. 138 static final String[] CONTACTS_SUMMARY_PROJECTION = new String[] { 139 People._ID, 140 People.DISPLAY_NAME, 141 }; 142 143 public Loader<Cursor> onCreateLoader(int id, Bundle args) { 144 // This is called when a new Loader needs to be created. This 145 // sample only has one Loader, so we don't care about the ID. 146 // First, pick the base URI to use depending on whether we are 147 // currently filtering. 148 Uri baseUri; 149 if (mCurFilter != null) { 150 baseUri = Uri.withAppendedPath(People.CONTENT_FILTER_URI, Uri.encode(mCurFilter)); 151 } else { 152 baseUri = People.CONTENT_URI; 153 } 154 155 // Now create and return a CursorLoader that will take care of 156 // creating a Cursor for the data being displayed. 157 String select = "((" + People.DISPLAY_NAME + " NOTNULL) AND (" 158 + People.DISPLAY_NAME + " != '' ))"; 159 return new CursorLoader(getActivity(), baseUri, 160 CONTACTS_SUMMARY_PROJECTION, select, null, 161 People.DISPLAY_NAME + " COLLATE LOCALIZED ASC"); 162 } 163 164 public void onLoadFinished(Loader<Cursor> loader, Cursor data) { 165 // Swap the new cursor in. (The framework will take care of closing the 166 // old cursor once we return.) 167 mAdapter.swapCursor(data); 168 169 // The list should now be shown. 170 if (isResumed()) { 171 setListShown(true); 172 } else { 173 setListShownNoAnimation(true); 174 } 175 } 176 177 public void onLoaderReset(Loader<Cursor> loader) { 178 // This is called when the last Cursor provided to onLoadFinished() 179 // above is about to be closed. We need to make sure we are no 180 // longer using it. 181 mAdapter.swapCursor(null); 182 } 183 } 184//END_INCLUDE(fragment_cursor) 185} 186