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.reflection; import android.content.Intent; import android.os.Bundle; import android.support.v4.app.Fragment; import android.support.v4.app.FragmentActivity; import android.support.v4.app.FragmentManager; import android.support.v4.app.FragmentTransaction; import android.view.Menu; import android.view.MenuItem; import com.facebook.AppEventsLogger; import com.facebook.Session; import com.facebook.SessionState; import com.facebook.UiLifecycleHelper; import com.facebook.reflection.R; public class MainActivity extends FragmentActivity { private static final String USER_SKIPPED_LOGIN_KEY = "user_skipped_login"; private static final int SPLASH = 0; private static final int SELECTION = 1; private static final int SETTINGS = 2; private static final int FRAGMENT_COUNT = SETTINGS + 1; private Fragment[] fragments = new Fragment[FRAGMENT_COUNT]; private MenuItem settings; private boolean isResumed = false; private boolean userSkippedLogin = false; private UiLifecycleHelper uiHelper; private Session.StatusCallback callback = new Session.StatusCallback() { @Override public void call(Session session, SessionState state, Exception exception) { onSessionStateChange(session, state, exception); } }; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); if (savedInstanceState != null) { userSkippedLogin = savedInstanceState.getBoolean(USER_SKIPPED_LOGIN_KEY); } uiHelper = new UiLifecycleHelper(this, callback); uiHelper.onCreate(savedInstanceState); setContentView(R.layout.main); FragmentManager fm = getSupportFragmentManager(); SplashFragment splashFragment = (SplashFragment) fm.findFragmentById(R.id.splashFragment); fragments[SPLASH] = splashFragment; fragments[SELECTION] = fm.findFragmentById(R.id.selectionFragment); fragments[SETTINGS] = fm.findFragmentById(R.id.userSettingsFragment); FragmentTransaction transaction = fm.beginTransaction(); for (int i = 0; i < fragments.length; i++) { transaction.hide(fragments[i]); } transaction.commit(); splashFragment.setSkipLoginCallback(new SplashFragment.SkipLoginCallback() { @Override public void onSkipLoginPressed() { userSkippedLogin = true; showFragment(SELECTION, false); } }); } @Override public void onResume() { super.onResume(); uiHelper.onResume(); isResumed = true; // Call the 'activateApp' method to log an app event for use in analytics and advertising reporting. Do so in // the onResume methods of the primary Activities that an app may be launched into. AppEventsLogger.activateApp(this); } @Override public void onPause() { super.onPause(); uiHelper.onPause(); isResumed = false; } @Override public void onActivityResult(int requestCode, int resultCode, Intent data) { super.onActivityResult(requestCode, resultCode, data); uiHelper.onActivityResult(requestCode, resultCode, data); } @Override public void onDestroy() { super.onDestroy(); uiHelper.onDestroy(); } @Override protected void onSaveInstanceState(Bundle outState) { super.onSaveInstanceState(outState); uiHelper.onSaveInstanceState(outState); outState.putBoolean(USER_SKIPPED_LOGIN_KEY, userSkippedLogin); } @Override protected void onResumeFragments() { super.onResumeFragments(); Session session = Session.getActiveSession(); if (session != null && session.isOpened()) { // if the session is already open, try to show the selection fragment showFragment(SELECTION, false); userSkippedLogin = false; } else if (userSkippedLogin) { showFragment(SELECTION, false); } else { // otherwise present the splash screen and ask the user to login, unless the user explicitly skipped. showFragment(SPLASH, false); } } @Override public boolean onPrepareOptionsMenu(Menu menu) { // only add the menu when the selection fragment is showing if (fragments[SELECTION].isVisible()) { if (menu.size() == 0) { settings = menu.add(R.string.settings); } return true; } else { menu.clear(); settings = null; } return false; } @Override public boolean onOptionsItemSelected(MenuItem item) { if (item.equals(settings)) { showSettingsFragment(); return true; } return false; } public void showSettingsFragment() { showFragment(SETTINGS, true); } private void onSessionStateChange(Session session, SessionState state, Exception exception) { if (isResumed) { FragmentManager manager = getSupportFragmentManager(); int backStackSize = manager.getBackStackEntryCount(); for (int i = 0; i < backStackSize; i++) { manager.popBackStack(); } // check for the OPENED state instead of session.isOpened() since for the // OPENED_TOKEN_UPDATED state, the selection fragment should already be showing. if (state.equals(SessionState.OPENED)) { showFragment(SELECTION, false); } else if (state.isClosed()) { showFragment(SPLASH, false); } } } private void showFragment(int fragmentIndex, boolean addToBackStack) { FragmentManager fm = getSupportFragmentManager(); FragmentTransaction transaction = fm.beginTransaction(); for (int i = 0; i < fragments.length; i++) { if (i == fragmentIndex) { transaction.show(fragments[i]); } else { transaction.hide(fragments[i]); } } if (addToBackStack) { transaction.addToBackStack(null); } transaction.commit(); } }