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/*
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* Copyright 2014 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package com.example.android.swiperefreshlayoutbasic;
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import com.example.android.common.dummydata.Cheeses;
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import com.example.android.common.logger.Log;
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import android.os.AsyncTask;
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import android.os.Bundle;
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import android.support.v4.app.Fragment;
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import android.support.v4.widget.SwipeRefreshLayout;
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import android.view.LayoutInflater;
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import android.view.Menu;
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import android.view.MenuInflater;
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import android.view.MenuItem;
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import android.view.View;
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import android.view.ViewGroup;
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import android.widget.ArrayAdapter;
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import android.widget.ListView;
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import java.util.List;
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/**
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* A basic sample that shows how to use {@link android.support.v4.widget.SwipeRefreshLayout} to add
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* the 'swipe-to-refresh' gesture to a layout. In this sample, SwipeRefreshLayout contains a
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* scrollable {@link android.widget.ListView} as its only child.
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*
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* <p>To provide an accessible way to trigger the refresh, this app also provides a refresh
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* action item.
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*
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* <p>In this sample app, the refresh updates the ListView with a random set of new items.
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*/
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public class SwipeRefreshLayoutBasicFragment extends Fragment {
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private static final String LOG_TAG = SwipeRefreshLayoutBasicFragment.class.getSimpleName();
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private static final int LIST_ITEM_COUNT = 20;
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/**
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* The {@link android.support.v4.widget.SwipeRefreshLayout} that detects swipe gestures and
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* triggers callbacks in the app.
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*/
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private SwipeRefreshLayout mSwipeRefreshLayout;
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/**
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* The {@link android.widget.ListView} that displays the content that should be refreshed.
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*/
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private ListView mListView;
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/**
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* The {@link android.widget.ListAdapter} used to populate the {@link android.widget.ListView}
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* defined in the previous statement.
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*/
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private ArrayAdapter<String> mListAdapter;
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@Override
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public void onCreate(Bundle savedInstanceState) {
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super.onCreate(savedInstanceState);
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// Notify the system to allow an options menu for this fragment.
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setHasOptionsMenu(true);
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}
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@Override
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public View onCreateView(LayoutInflater inflater, ViewGroup container,
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Bundle savedInstanceState) {
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View view = inflater.inflate(R.layout.fragment_sample, container, false);
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// Retrieve the SwipeRefreshLayout and ListView instances
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mSwipeRefreshLayout = (SwipeRefreshLayout) view.findViewById(R.id.swiperefresh);
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// Set the color scheme of the SwipeRefreshLayout by providing 4 color resource ids
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mSwipeRefreshLayout.setColorScheme(
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R.color.swipe_color_1, R.color.swipe_color_2,
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R.color.swipe_color_3, R.color.swipe_color_4);
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// Retrieve the ListView
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mListView = (ListView) view.findViewById(android.R.id.list);
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return view;
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}
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@Override
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public void onViewCreated(View view, Bundle savedInstanceState) {
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super.onViewCreated(view, savedInstanceState);
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/**
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* Create an ArrayAdapter to contain the data for the ListView. Each item in the ListView
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* uses the system-defined simple_list_item_1 layout that contains one TextView.
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*/
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mListAdapter = new ArrayAdapter<String>(
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getActivity(),
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android.R.layout.simple_list_item_1,
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android.R.id.text1,
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Cheeses.randomList(LIST_ITEM_COUNT));
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// Set the adapter between the ListView and its backing data.
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mListView.setAdapter(mListAdapter);
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/**
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* Implement {@link SwipeRefreshLayout.OnRefreshListener}. When users do the "swipe to
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* refresh" gesture, SwipeRefreshLayout invokes
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* {@link SwipeRefreshLayout.OnRefreshListener#onRefresh onRefresh()}. In
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* {@link SwipeRefreshLayout.OnRefreshListener#onRefresh onRefresh()}, call a method that
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* refreshes the content. Call the same method in response to the Refresh action from the
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* action bar.
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*/
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mSwipeRefreshLayout.setOnRefreshListener(new SwipeRefreshLayout.OnRefreshListener() {
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@Override
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public void onRefresh() {
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Log.i(LOG_TAG, "onRefresh called from SwipeRefreshLayout");
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initiateRefresh();
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}
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});
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}
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@Override
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public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
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inflater.inflate(R.menu.main_menu, menu);
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}
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/**
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* Respond to the user's selection of the Refresh action item. Start the SwipeRefreshLayout
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* progress bar, then initiate the background task that refreshes the content.
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*/
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@Override
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public boolean onOptionsItemSelected(MenuItem item) {
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switch (item.getItemId()) {
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case R.id.menu_refresh:
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Log.i(LOG_TAG, "Refresh menu item selected");
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// We make sure that the SwipeRefreshLayout is displaying it's refreshing indicator
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if (!mSwipeRefreshLayout.isRefreshing()) {
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mSwipeRefreshLayout.setRefreshing(true);
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}
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// Start our refresh background task
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initiateRefresh();
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return true;
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}
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return super.onOptionsItemSelected(item);
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}
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/**
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* By abstracting the refresh process to a single method, the app allows both the
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* SwipeGestureLayout onRefresh() method and the Refresh action item to refresh the content.
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*/
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private void initiateRefresh() {
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Log.i(LOG_TAG, "initiateRefresh");
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/**
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* Execute the background task, which uses {@link android.os.AsyncTask} to load the data.
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*/
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new DummyBackgroundTask().execute();
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}
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/**
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* When the AsyncTask finishes, it calls onRefreshComplete(), which updates the data in the
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* ListAdapter and turns off the progress bar.
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*/
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private void onRefreshComplete(List<String> result) {
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Log.i(LOG_TAG, "onRefreshComplete");
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// Remove all items from the ListAdapter, and then replace them with the new items
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mListAdapter.clear();
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for (String cheese : result) {
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mListAdapter.add(cheese);
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}
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// Stop the refreshing indicator
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mSwipeRefreshLayout.setRefreshing(false);
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}
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/**
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* Dummy {@link AsyncTask} which simulates a long running task to fetch new cheeses.
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*/
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private class DummyBackgroundTask extends AsyncTask<Void, Void, List<String>> {
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static final int TASK_DURATION = 3 * 1000; // 3 seconds
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@Override
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protected List<String> doInBackground(Void... params) {
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// Sleep for a small amount of time to simulate a background-task
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try {
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Thread.sleep(TASK_DURATION);
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} catch (InterruptedException e) {
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e.printStackTrace();
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}
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// Return a new random list of cheeses
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return Cheeses.randomList(LIST_ITEM_COUNT);
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}
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@Override
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protected void onPostExecute(List<String> result) {
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super.onPostExecute(result);
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// Tell the Fragment that the refresh has completed
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onRefreshComplete(result);
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}
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}
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}