Java tutorial
/* * Copyright 2013 Inderjit Gill * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package io.indy.drone.fragment; import android.app.Activity; import android.content.Intent; import android.database.Cursor; import android.os.AsyncTask; import android.os.Bundle; import android.support.v4.app.ListFragment; import android.util.Log; import android.view.View; import android.view.ViewGroup; import android.widget.ListView; import de.greenrobot.event.EventBus; import io.indy.drone.AppConfig; import io.indy.drone.activity.StrikeListActivity; import io.indy.drone.adapter.StrikeCursorAdapter; import io.indy.drone.event.UpdatedDatabaseEvent; import io.indy.drone.model.SQLDatabase; import io.indy.drone.service.ScheduledService; import uk.co.senab.actionbarpulltorefresh.library.ActionBarPullToRefresh; import uk.co.senab.actionbarpulltorefresh.library.PullToRefreshLayout; import uk.co.senab.actionbarpulltorefresh.library.listeners.OnRefreshListener; /** * A list fragment representing a list of Strikes. This fragment * also supports tablet devices by allowing list items to be given an * 'activated' state upon selection. This helps indicate which item is * currently being viewed in a {@link io.indy.drone.fragment.StrikeDetailFragment}. * <p/> * Activities containing this fragment MUST implement the {@link Callbacks} * interface. */ public class StrikeListFragment extends ListFragment { static private final boolean D = true; static private final String TAG = "StrikeListFragment"; static void ifd(final String message) { if (AppConfig.DEBUG && D) Log.d(TAG, message); } private SQLDatabase mDatabase; private PullToRefreshLayout mPullToRefreshLayout; private StrikeCursorAdapter mStrikeCursorAdapter; private String mLocation; /** * The serialization (saved instance state) Bundle key representing the * activated item position. Only used on tablets. */ private static final String STATE_ACTIVATED_POSITION = "activated_position"; /** * The fragment's current callback object, which is notified of list item * clicks. */ private Callbacks mCallbacks = sDummyCallbacks; /** * The current activated item position. Only used on tablets. */ private int mActivatedPosition = ListView.INVALID_POSITION; /** * A callback interface that all activities containing this fragment must * implement. This mechanism allows activities to be notified of item * selections. */ public interface Callbacks { /** * Callback for when an item has been selected. */ public void onItemSelected(String id); } /** * A dummy implementation of the {@link Callbacks} interface that does * nothing. Used only when this fragment is not attached to an activity. */ private static Callbacks sDummyCallbacks = new Callbacks() { @Override public void onItemSelected(String id) { } }; /** * Mandatory empty constructor for the fragment manager to instantiate the * fragment (e.g. upon screen orientation changes). */ public StrikeListFragment() { } @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); try { mLocation = SQLDatabase.regionFromIndex(0); // worldwide } catch (IndexOutOfBoundsException e) { e.printStackTrace(); } } @Override public void onActivityCreated(Bundle savedInstanceState) { super.onActivityCreated(savedInstanceState); mDatabase = new SQLDatabase(getActivity()); Cursor c = mDatabase.getStrikeCursor(mLocation, true); mStrikeCursorAdapter = new StrikeCursorAdapter(getActivity(), c, 0); setListAdapter(mStrikeCursorAdapter); } @Override public void onViewCreated(View view, Bundle savedInstanceState) { super.onViewCreated(view, savedInstanceState); ListView lv = getListView(); lv.setDivider(null); lv.setDividerHeight(0); // Restore the previously serialized activated item position. if (savedInstanceState != null && savedInstanceState.containsKey(STATE_ACTIVATED_POSITION)) { setActivatedPosition(savedInstanceState.getInt(STATE_ACTIVATED_POSITION)); } // This is the View which is created by ListFragment ViewGroup viewGroup = (ViewGroup) view; // We need to create a PullToRefreshLayout manually mPullToRefreshLayout = new PullToRefreshLayout(viewGroup.getContext()); // We can now setup the PullToRefreshLayout ActionBarPullToRefresh.from(getActivity()) // We need to insert the PullToRefreshLayout into the Fragment's ViewGroup .insertLayoutInto(viewGroup) // We need to mark the ListView and it's Empty View as pullable // This is because they are not direct children of the ViewGroup .theseChildrenArePullable(getListView(), getListView().getEmptyView()) // We can now complete the setup as desired .listener(new OnRefreshListener() { @Override public void onRefreshStarted(View view) { Intent intent = new Intent(getActivity(), ScheduledService.class); intent.putExtra(StrikeListActivity.ResponseReceiver.IS_PTR, true); getActivity().startService(intent); } }).setup(mPullToRefreshLayout); } public void stopPullToRefreshProgress() { mPullToRefreshLayout.setRefreshComplete(); } @Override public void onAttach(Activity activity) { super.onAttach(activity); // Activities containing this fragment must implement its callbacks. if (!(activity instanceof Callbacks)) { throw new IllegalStateException("Activity must implement fragment's callbacks."); } mCallbacks = (Callbacks) activity; } @Override public void onDetach() { super.onDetach(); // Reset the active callbacks interface to the dummy implementation. mCallbacks = sDummyCallbacks; } @Override public void onStart() { super.onStart(); ifd("onStart"); EventBus.getDefault().register(this); } @Override public void onStop() { super.onStop(); ifd("onStop"); EventBus.getDefault().unregister(this); } @Override public void onDestroy() { ifd("onDestroy"); mDatabase.closeDatabase(); super.onDestroy(); } @SuppressWarnings({ "UnusedDeclaration" }) public void onEvent(UpdatedDatabaseEvent event) { ifd("received UpdatedDatabaseEvent"); updateStrikeCursor(); } @Override public void onListItemClick(ListView listView, View view, int position, long id) { super.onListItemClick(listView, view, position, id); // Notify the active callbacks interface (the activity, if the // fragment is attached to one) that an item has been selected. mCallbacks.onItemSelected(Long.toString(id)); } @Override public void onSaveInstanceState(Bundle outState) { super.onSaveInstanceState(outState); if (mActivatedPosition != ListView.INVALID_POSITION) { // Serialize and persist the activated item position. outState.putInt(STATE_ACTIVATED_POSITION, mActivatedPosition); } } public void onRegionClicked(String region) { mLocation = region; updateStrikeCursor(); } private void updateStrikeCursor() { Cursor cursor = mDatabase.getStrikeCursor(mLocation, true); mStrikeCursorAdapter.changeCursor(cursor); mStrikeCursorAdapter.notifyDataSetChanged(); } /** * Turns on activate-on-click mode. When this mode is on, list items will be * given the 'activated' state when touched. */ public void setActivateOnItemClick(boolean activateOnItemClick) { // When setting CHOICE_MODE_SINGLE, ListView will automatically // give items the 'activated' state when touched. getListView().setChoiceMode(activateOnItemClick ? ListView.CHOICE_MODE_SINGLE : ListView.CHOICE_MODE_NONE); } private void setActivatedPosition(int position) { if (position == ListView.INVALID_POSITION) { getListView().setItemChecked(mActivatedPosition, false); } else { getListView().setItemChecked(position, true); } mActivatedPosition = position; } }