Java tutorial
/******************************************************************************* * This file is part of GPSLogger for Android. * * GPSLogger for Android is free software: you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation, either version 2 of the License, or * (at your option) any later version. * * GPSLogger for Android is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with GPSLogger for Android. If not, see <http://www.gnu.org/licenses/>. ******************************************************************************/ package com.mendhak.gpslogger; import android.app.ActionBar; import android.app.Activity; import android.app.Fragment; import android.content.SharedPreferences; import android.content.res.Configuration; import android.os.Bundle; import android.preference.PreferenceManager; import android.support.v4.app.ActionBarDrawerToggle; import android.support.v4.view.GravityCompat; import android.support.v4.widget.DrawerLayout; import android.view.LayoutInflater; import android.view.MenuItem; import android.view.View; import android.view.ViewGroup; import android.widget.AdapterView; import android.widget.ArrayAdapter; import android.widget.ListView; import java.util.ArrayList; ; /** * Fragment used for managing interactions for and presentation of a navigation drawer. * See the <a href="https://developer.android.com/design/patterns/navigation-drawer.html#Interaction"> * design guidelines</a> for a complete explanation of the behaviors implemented here. */ public class NavigationDrawerFragment extends Fragment { /** * Remember the position of the selected item. */ private static final String STATE_SELECTED_POSITION = "selected_navigation_drawer_position"; /** * Per the design guidelines, you should show the drawer on launch until the user manually * expands it. This shared preference tracks this. */ private static final String PREF_USER_SEEN_DRAWER = "navigation_drawer_learned"; /** * A pointer to the current callbacks instance (the Activity). */ private NavigationDrawerCallbacks navigationDrawerCallbacks; /** * Helper component that ties the action bar to the navigation drawer. */ private ActionBarDrawerToggle actionBarDrawerToggle; private DrawerLayout drawerLayout; private ListView drawerListView; private View fragmentContainerView; private int currentSelectedPosition = 0; private boolean fromSavedInstanceState; private boolean userHasSeenDrawer; public NavigationDrawerFragment() { } @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); // Read in the flag indicating whether or not the user has demonstrated awareness of the // drawer. See PREF_USER_SEEN_DRAWER for details. SharedPreferences sp = PreferenceManager.getDefaultSharedPreferences(getActivity()); userHasSeenDrawer = sp.getBoolean(PREF_USER_SEEN_DRAWER, false); if (savedInstanceState != null) { currentSelectedPosition = savedInstanceState.getInt(STATE_SELECTED_POSITION); fromSavedInstanceState = true; } // Select either the default item (0) or the last selected item. //selectItem(currentSelectedPosition); selectItem(0); } @Override public void onActivityCreated(Bundle savedInstanceState) { super.onActivityCreated(savedInstanceState); // Indicate that this fragment would like to influence the set of actions in the action bar. setHasOptionsMenu(true); } @Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { drawerListView = (ListView) inflater.inflate(R.layout.fragment_navigation_drawer, container, false); drawerListView.setOnItemClickListener(new AdapterView.OnItemClickListener() { @Override public void onItemClick(AdapterView<?> parent, View view, int position, long id) { selectItem(position); } }); ArrayList<String> drawerMenuItems = new ArrayList<String>(); drawerMenuItems.add(getString(R.string.title_drawer_headsettings)); drawerMenuItems.add(getString(R.string.title_drawer_generalsettings)); drawerMenuItems.add(getString(R.string.title_drawer_loggingsettings)); drawerMenuItems.add(getString(R.string.title_drawer_uploadsettings)); drawerMenuItems.add(" " + getString(R.string.autoftp_setup_title)); drawerMenuItems.add(getString(R.string.menu_exit)); drawerListView.setAdapter(new ArrayAdapter<String>(getActionBar().getThemedContext(), android.R.layout.simple_list_item_activated_1, android.R.id.text1, drawerMenuItems.toArray(new String[0]))); drawerListView.setItemChecked(currentSelectedPosition, true); return drawerListView; } public boolean isDrawerOpen() { return drawerLayout != null && drawerLayout.isDrawerOpen(fragmentContainerView); } /** * Users of this fragment must call this method to set up the navigation drawer interactions. * * @param fragmentId The android:id of this fragment in its activity's layout. * @param drawerLayout The DrawerLayout containing this fragment's UI. */ public void setUp(int fragmentId, DrawerLayout drawerLayout) { fragmentContainerView = getActivity().findViewById(fragmentId); this.drawerLayout = drawerLayout; // set a custom shadow that overlays the main content when the drawer opens this.drawerLayout.setDrawerShadow(R.drawable.drawer_shadow, GravityCompat.START); // set up the drawer's list view with items and click listener ActionBar actionBar = getActionBar(); actionBar.setDisplayHomeAsUpEnabled(true); actionBar.setHomeButtonEnabled(true); // ActionBarDrawerToggle ties together the the proper interactions // between the navigation drawer and the action bar app icon. actionBarDrawerToggle = new ActionBarDrawerToggle(getActivity(), /* host Activity */ NavigationDrawerFragment.this.drawerLayout, /* DrawerLayout object */ R.drawable.ic_drawer, /* nav drawer image to replace 'Up' caret */ R.string.navigation_drawer_open, /* "open drawer" description for accessibility */ R.string.navigation_drawer_close /* "close drawer" description for accessibility */ ) { @Override public void onDrawerClosed(View drawerView) { super.onDrawerClosed(drawerView); if (!isAdded()) { return; } getActivity().invalidateOptionsMenu(); // calls onPrepareOptionsMenu() } @Override public void onDrawerOpened(View drawerView) { super.onDrawerOpened(drawerView); if (!isAdded()) { return; } getActivity().invalidateOptionsMenu(); // calls onPrepareOptionsMenu() } }; // If the user hasn't 'learned' about the drawer, open it to introduce them to the drawer, // per the navigation drawer design guidelines. if (!userHasSeenDrawer && !fromSavedInstanceState) { this.drawerLayout.openDrawer(fragmentContainerView); SharedPreferences sp = PreferenceManager.getDefaultSharedPreferences(getActivity()); sp.edit().putBoolean(PREF_USER_SEEN_DRAWER, true).apply(); } // Defer code dependent on restoration of previous instance state. this.drawerLayout.post(new Runnable() { @Override public void run() { actionBarDrawerToggle.syncState(); } }); this.drawerLayout.setDrawerListener(actionBarDrawerToggle); } public void toggleDrawer() { if (isDrawerOpen()) { drawerLayout.closeDrawer(fragmentContainerView); } else { drawerLayout.openDrawer(fragmentContainerView); } } private void selectItem(int position) { currentSelectedPosition = position; if (drawerListView != null) { drawerListView.setItemChecked(position, true); } if (drawerLayout != null) { drawerLayout.closeDrawer(fragmentContainerView); } if (navigationDrawerCallbacks != null) { navigationDrawerCallbacks.onNavigationDrawerItemSelected(position); } } @Override public void onAttach(Activity activity) { super.onAttach(activity); try { navigationDrawerCallbacks = (NavigationDrawerCallbacks) activity; } catch (ClassCastException e) { throw new ClassCastException("Activity must implement NavigationDrawerCallbacks."); } } @Override public void onDetach() { super.onDetach(); navigationDrawerCallbacks = null; } @Override public void onSaveInstanceState(Bundle outState) { //Bug: http://stackoverflow.com/questions/7575921/illegalstateexception-can-not-perform-this-action-after-onsaveinstancestate-h outState.putInt(STATE_SELECTED_POSITION, currentSelectedPosition); super.onSaveInstanceState(outState); } @Override public void onConfigurationChanged(Configuration newConfig) { super.onConfigurationChanged(newConfig); // Forward the new configuration the drawer toggle component. actionBarDrawerToggle.onConfigurationChanged(newConfig); } @Override public boolean onOptionsItemSelected(MenuItem item) { //Required to show the left drawer if (actionBarDrawerToggle != null && actionBarDrawerToggle.onOptionsItemSelected(item)) { return true; } return super.onOptionsItemSelected(item); } private ActionBar getActionBar() { return getActivity().getActionBar(); } /** * Callbacks interface that all activities using this fragment must implement. */ public static interface NavigationDrawerCallbacks { /** * Called when an item in the navigation drawer is selected. */ void onNavigationDrawerItemSelected(int position); } }