1 /* 2 * Copyright 2014 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.swiperefreshmultipleviews; 18 19 import com.example.android.common.dummydata.Cheeses; 20 import com.example.android.common.logger.Log; 21 22 import android.os.AsyncTask; 23 import android.os.Bundle; 24 import android.support.v4.app.Fragment; 25 import android.support.v4.widget.SwipeRefreshLayout; 26 import android.view.LayoutInflater; 27 import android.view.Menu; 28 import android.view.MenuInflater; 29 import android.view.MenuItem; 30 import android.view.View; 31 import android.view.ViewGroup; 32 import android.widget.ArrayAdapter; 33 import android.widget.GridView; 34 35 import java.util.List; 36 37 /** 38 * A sample which shows how to use {@link android.support.v4.widget.SwipeRefreshLayout} to add 39 * the 'swipe-to-refresh' gesture to a layout with multiple children. In this sample, 40 * SwipeRefreshLayout contains a scrollable {@link android.widget.GridView}, along with a 41 * {@link android.widget.TextView} empty view. 42 * 43 * <p>To provide an accessible way to trigger the refresh, this app also provides a refresh 44 * action item. 45 * 46 * <p>In this sample app, the refresh updates the GridView with a random set of new items. 47 */ 48 public class SwipeRefreshMultipleViewsFragment extends Fragment { 49 50 private static final String LOG_TAG = SwipeRefreshMultipleViewsFragment.class.getSimpleName(); 51 52 private static final int LIST_ITEM_COUNT = 40; 53 54 /** 55 * The {@link MultiSwipeRefreshLayout} that detects swipe gestures and triggers callbacks in 56 * the app. 57 */ 58 private MultiSwipeRefreshLayout mSwipeRefreshLayout; 59 60 /** 61 * The {@link android.widget.GridView} that displays the content that should be refreshed. 62 */ 63 private GridView mGridView; 64 65 /** 66 * The {@link android.widget.ListAdapter} used to populate the {@link android.widget.GridView} 67 * defined in the previous statement. 68 */ 69 private ArrayAdapter<String> mListAdapter; 70 71 /** 72 * The {@link View} which is displayed when the GridView is empty. 73 */ 74 private View mEmptyView; 75 76 @Override 77 public void onCreate(Bundle savedInstanceState) { 78 super.onCreate(savedInstanceState); 79 80 // Notify the system to allow an options menu for this fragment. 81 setHasOptionsMenu(true); 82 } 83 85 @Override 86 public View onCreateView(LayoutInflater inflater, ViewGroup container, 87 Bundle savedInstanceState) { 88 View view = inflater.inflate(R.layout.fragment_sample, container, false); 89 90 // Retrieve the SwipeRefreshLayout and GridView instances 91 mSwipeRefreshLayout = (MultiSwipeRefreshLayout) view.findViewById(R.id.swiperefresh); 92 94 // Set the color scheme of the SwipeRefreshLayout by providing 4 color resource ids 95 mSwipeRefreshLayout.setColorScheme( 96 R.color.swipe_color_1, R.color.swipe_color_2, 97 R.color.swipe_color_3, R.color.swipe_color_4); 99 100 // Retrieve the GridView 101 mGridView = (GridView) view.findViewById(android.R.id.list); 102 103 // Retrieve the empty view 104 mEmptyView = view.findViewById(android.R.id.empty); 105 106 return view; 107 } 109 111 @Override 112 public void onViewCreated(View view, Bundle savedInstanceState) { 113 super.onViewCreated(view, savedInstanceState); 114 115 /** 116 * Create an ArrayAdapter to contain the data for the GridView. Each item in the GridView 117 * uses the system-defined simple_list_item_1 layout that contains one TextView. Initially 118 */ 119 mListAdapter = new ArrayAdapter<String>( 120 getActivity(), 121 android.R.layout.simple_list_item_1, 122 android.R.id.text1); 123 124 // Set the adapter between the GridView and its backing data. 125 mGridView.setAdapter(mListAdapter); 126 127 // Set the empty view so that it is displayed as needed 128 mGridView.setEmptyView(mEmptyView); 129 131 // Tell the MultiSwipeRefreshLayout which views are swipeable. In this case, the GridView 132 // and empty view. 133 mSwipeRefreshLayout.setSwipeableChildren(android.R.id.list, android.R.id.empty); 135 137 /** 138 * Implement {@link SwipeRefreshLayout.OnRefreshListener}. When users do the "swipe to 139 * refresh" gesture, SwipeRefreshLayout invokes 140 * {@link SwipeRefreshLayout.OnRefreshListener#onRefresh onRefresh()}. In 141 * {@link SwipeRefreshLayout.OnRefreshListener#onRefresh onRefresh()}, call a method that 142 * refreshes the content. Call the same method in response to the Refresh action from the 143 * action bar. 144 */ 145 mSwipeRefreshLayout.setOnRefreshListener(new SwipeRefreshLayout.OnRefreshListener() { 146 @Override 147 public void onRefresh() { 148 Log.i(LOG_TAG, "onRefresh called from SwipeRefreshLayout"); 149 150 initiateRefresh(); 151 } 152 }); 154 } 156 157 @Override 158 public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) { 159 inflater.inflate(R.menu.main_menu, menu); 160 } 161 163 /** 164 * Respond to the user's selection of the Refresh action item. Start the SwipeRefreshLayout 165 * progress bar, then initiate the background task that refreshes the content. 166 */ 167 @Override 168 public boolean onOptionsItemSelected(MenuItem item) { 169 switch (item.getItemId()) { 170 case R.id.menu_clear: 171 Log.i(LOG_TAG, "Clear menu item selected"); 172 mListAdapter.clear(); 173 return true; 174 175 case R.id.menu_refresh: 176 Log.i(LOG_TAG, "Refresh menu item selected"); 177 178 // We make sure that the SwipeRefreshLayout is displaying it's refreshing indicator 179 if (!mSwipeRefreshLayout.isRefreshing()) { 180 mSwipeRefreshLayout.setRefreshing(true); 181 } 182 183 // Start our refresh background task 184 initiateRefresh(); 185 186 return true; 187 } 188 189 return super.onOptionsItemSelected(item); 190 } 192 194 /** 195 * By abstracting the refresh process to a single method, the app allows both the 196 * SwipeGestureLayout onRefresh() method and the Refresh action item to refresh the content. 197 */ 198 private void initiateRefresh() { 199 Log.i(LOG_TAG, "initiateRefresh"); 200 201 /** 202 * Execute the background task, which uses {@link android.os.AsyncTask} to load the data. 203 */ 204 new DummyBackgroundTask().execute(); 205 } 207 209 /** 210 * When the AsyncTask finishes, it calls onRefreshComplete(), which updates the data in the 211 * ListAdapter and turns off the progress bar. 212 */ 213 private void onRefreshComplete(List<String> result) { 214 Log.i(LOG_TAG, "onRefreshComplete"); 215 216 // Remove all items from the ListAdapter, and then replace them with the new items 217 mListAdapter.clear(); 218 for (String cheese : result) { 219 mListAdapter.add(cheese); 220 } 221 222 // Stop the refreshing indicator 223 mSwipeRefreshLayout.setRefreshing(false); 224 } 226 227 /** 228 * Dummy {@link AsyncTask} which simulates a long running task to fetch new cheeses. 229 */ 230 private class DummyBackgroundTask extends AsyncTask<Void, Void, List<String>> { 231 232 static final int TASK_DURATION = 3 * 1000; // 3 seconds 233 234 @Override 235 protected List<String> doInBackground(Void... params) { 236 // Sleep for a small amount of time to simulate a background-task 237 try { 238 Thread.sleep(TASK_DURATION); 239 } catch (InterruptedException e) { 240 e.printStackTrace(); 241 } 242 243 // Return a new random list of cheeses 244 return Cheeses.randomList(LIST_ITEM_COUNT); 245 } 246 247 @Override 248 protected void onPostExecute(List<String> result) { 249 super.onPostExecute(result); 250 251 // Tell the Fragment that the refresh has completed 252 onRefreshComplete(result); 253 } 254 255 } 256 }