Java tutorial
/** * Copyright 2010-present Facebook. * * 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 com.facebook.samples.switchuser; import android.content.Context; import android.content.SharedPreferences; import android.os.Bundle; import android.support.v4.app.ListFragment; import android.view.*; import android.widget.*; import com.facebook.model.GraphUser; import com.facebook.widget.ProfilePictureView; import com.facebook.SessionLoginBehavior; import java.util.ArrayList; import java.util.Arrays; public class SettingsFragment extends ListFragment { public static final String TAG = "SettingsFragment"; private static final String CURRENT_SLOT_KEY = "CurrentSlot"; private SlotManager slotManager; private OnSlotChangedListener slotChangedListener; private boolean hasPendingNotifySlotChanged; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); slotManager = new SlotManager(); slotManager.restore(getActivity(), savedInstanceState != null ? savedInstanceState.getInt(CURRENT_SLOT_KEY, SlotManager.NO_SLOT) : SlotManager.NO_SLOT); ArrayList<Slot> slotList = new ArrayList<Slot>(Arrays.asList(slotManager.getAllSlots())); setListAdapter(new SlotAdapter(slotList)); } @Override public View onCreateView(LayoutInflater inflater, ViewGroup parent, Bundle savedInstanceState) { View view = super.onCreateView(inflater, parent, savedInstanceState); registerForContextMenu(view.findViewById(android.R.id.list)); return view; } @Override public void onCreateContextMenu(ContextMenu menu, View view, ContextMenu.ContextMenuInfo menuInfo) { super.onCreateContextMenu(menu, view, menuInfo); getActivity().getMenuInflater().inflate(R.menu.context_settings, menu); } @Override public void onListItemClick(ListView l, View view, int position, long id) { slotManager.toggleSlot(position); } @Override public boolean onContextItemSelected(MenuItem item) { AdapterView.AdapterContextMenuInfo info = (AdapterView.AdapterContextMenuInfo) item.getMenuInfo(); SlotAdapter adapter = (SlotAdapter) getListAdapter(); Slot slot = adapter.getItem(info.position); switch (item.getItemId()) { case R.id.menu_item_clear_slot: if (slot.getUserId() != null) { // Clear out data that this app stored in the cache // Not calling Session.closeAndClearTokenInformation() because we have additional // data stored in the cache. slot.clear(); if (slot == slotManager.getSelectedSlot()) { slotManager.toggleSlot(info.position); } updateListView(); } return true; } return super.onContextItemSelected(item); } @Override public void onSaveInstanceState(Bundle outState) { super.onSaveInstanceState(outState); outState.putInt(CURRENT_SLOT_KEY, slotManager.getSelectedSlotNumber()); } public void setSlotChangedListener(OnSlotChangedListener listener) { slotChangedListener = listener; if (listener != null && hasPendingNotifySlotChanged) { notifySlotChanged(); hasPendingNotifySlotChanged = false; } } public void updateViewForUser(GraphUser user) { if (slotManager == null) { // Fragment has not had onCreate called yet. return; } if (user != null) { Slot s = slotManager.getSelectedSlot(); if (s != null) { s.update(user); } } else { // If the user is null, then there isn't an actively selected // user. This can happen if the user cancelled a login. So make sure that // SlotManager is updated properly. slotManager.setSelectedSlotNumber(SlotManager.NO_SLOT); } updateListView(); } private void notifySlotChanged() { OnSlotChangedListener listener = slotChangedListener; if (listener != null) { Slot newSlot = slotManager.getSelectedSlot(); listener.onSlotChanged(newSlot); } else { hasPendingNotifySlotChanged = true; } } private void updateListView() { SlotAdapter adapter = (SlotAdapter) getListAdapter(); adapter.notifyDataSetChanged(); } public interface OnSlotChangedListener { void onSlotChanged(Slot newSlot); } private class SlotAdapter extends ArrayAdapter<Slot> { public SlotAdapter(ArrayList<Slot> slots) { super(getActivity(), android.R.layout.simple_list_item_1, slots); } @Override public View getView(int position, View convertView, ViewGroup parent) { if (null == convertView) { convertView = getActivity().getLayoutInflater().inflate(R.layout.list_item_user, null); } Slot slot = getItem(position); String userName = slot.getUserName(); if (userName == null) { userName = getString(R.string.empty_slot); } ProfilePictureView profilePictureView = (ProfilePictureView) convertView.findViewById(R.id.slotPic); profilePictureView.setCropped(true); profilePictureView.setProfileId(slot.getUserId()); TextView userNameTextView = (TextView) convertView.findViewById(R.id.slotUserName); userNameTextView.setText(userName); CheckBox currentUserCheckBox = (CheckBox) convertView.findViewById(R.id.currentUserIndicator); currentUserCheckBox.setChecked(slotManager.getSelectedSlot() == slot); return convertView; } } private class SlotManager { static final int NO_SLOT = -1; private final static int MAX_SLOTS = 4; private static final String SETTINGS_CURRENT_SLOT_KEY = "CurrentSlot"; private static final String SETTINGS_NAME = "UserManagerSettings"; private SharedPreferences settings; private int selectedSlotNumber = NO_SLOT; private Slot[] slots; void restore(Context context, int oldSelectedSlot) { if (context == null) { throw new IllegalArgumentException("context cannot be null"); } Context applicationContext = context.getApplicationContext(); applicationContext = (applicationContext == null) ? context : applicationContext; slots = new Slot[MAX_SLOTS]; for (int i = 0; i < MAX_SLOTS; i++) { SessionLoginBehavior loginBehavior = (i == 0) ? SessionLoginBehavior.SSO_WITH_FALLBACK : SessionLoginBehavior.SUPPRESS_SSO; slots[i] = new Slot(applicationContext, i, loginBehavior); } // Restore the last known state from when the app ran last. settings = applicationContext.getSharedPreferences(SETTINGS_NAME, Context.MODE_PRIVATE); int savedSlotNumber = settings.getInt(SETTINGS_CURRENT_SLOT_KEY, NO_SLOT); if (savedSlotNumber != NO_SLOT && savedSlotNumber != oldSelectedSlot) { // This will trigger the full flow of creating and opening the right session toggleSlot(savedSlotNumber); } else { // We already knew which slot was selected. So don't notify that a new slot was // selected since that will close out the old session and recreate a new one. And // doing so will have the effect of clearing out state like the profile pic. setSelectedSlotNumber(savedSlotNumber); } } void toggleSlot(int slot) { validateSlot(slot); if (slot == selectedSlotNumber) { setSelectedSlotNumber(NO_SLOT); } else { setSelectedSlotNumber(slot); } notifySlotChanged(); } Slot getSelectedSlot() { if (selectedSlotNumber == NO_SLOT) { return null; } else { return getSlot(selectedSlotNumber); } } int getSelectedSlotNumber() { return selectedSlotNumber; } Slot[] getAllSlots() { return slots; } Slot getSlot(int slot) { validateSlot(slot); return slots[slot]; } private void setSelectedSlotNumber(int slot) { // Store the selected slot number for when the app is closed and restarted settings.edit().putInt(SETTINGS_CURRENT_SLOT_KEY, slot).commit(); selectedSlotNumber = slot; } private void validateSlot(int slot) { if (slot <= NO_SLOT || slot >= MAX_SLOTS) { throw new IllegalArgumentException( String.format("Choose a slot between 0 and %d inclusively", MAX_SLOTS - 1)); } } } }