Java tutorial
// Copyright (c) 2015, the Dartino project authors. Please see the AUTHORS file // for details. All rights reserved. Use of this source code is governed by a // BSD-style license that can be found in the LICENSE.md file. package com.google.dartino.githubsample; import android.app.ActionBar; import android.support.v7.app.ActionBarDrawerToggle; import android.support.v4.view.GravityCompat; import android.support.v4.widget.DrawerLayout; import android.content.SharedPreferences; import android.content.res.Configuration; import android.os.Bundle; import android.preference.PreferenceManager; import android.view.LayoutInflater; import android.view.Menu; import android.view.MenuInflater; import android.view.MenuItem; import android.view.View; import android.view.ViewGroup; import android.widget.ListView; import com.google.dartino.immisamples.Drawer; /** * 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 Drawer.PaneFragment { 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_LEARNED_DRAWER for details. SharedPreferences sp = PreferenceManager.getDefaultSharedPreferences(getActivity()); userLearnedDrawer = sp.getBoolean(PREF_USER_LEARNED_DRAWER, false); if (savedInstanceState != null) { fromSavedInstanceState = true; } } @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); return drawerListView; } public boolean isDrawerOpen() { return drawerLayout != null && drawerLayout.isDrawerOpen(getView()); } @Override public void setOpenedState(boolean open) { // TODO(zerny): getView might return null here!? Reintroduce setup of the view in setup(...). View view = getView(); if (view == null) return; if (open) { drawerLayout.openDrawer(view); } else { drawerLayout.closeDrawer(view); } } public void setupMenu(com.google.dartino.immisamples.Menu menu) { menu.setListView(drawerListView); } /** * Users of this fragment must call this method to set up the navigation drawer interactions. * * @param drawerLayout The DrawerLayout containing this fragment's UI. * @param presenter The Drawer.PanePresenter associated with this fragment. */ @Override public void setup(DrawerLayout drawerLayout, Drawer.PanePresenter presenter) { this.drawerLayout = drawerLayout; this.panePresenter = presenter; // 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. drawerToggle = new ActionBarDrawerToggle(getActivity(), /* host Activity */ NavigationDrawerFragment.this.drawerLayout, /* DrawerLayout object */ 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; } NavigationDrawerFragment.this.panePresenter.close(); getActivity().invalidateOptionsMenu(); // calls onPrepareOptionsMenu() } @Override public void onDrawerOpened(View drawerView) { super.onDrawerOpened(drawerView); if (!isAdded()) { return; } NavigationDrawerFragment.this.panePresenter.open(); if (!userLearnedDrawer) { // The user manually opened the drawer; store this flag to prevent auto-showing // the navigation drawer automatically in the future. userLearnedDrawer = true; SharedPreferences sp = PreferenceManager.getDefaultSharedPreferences(getActivity()); sp.edit().putBoolean(PREF_USER_LEARNED_DRAWER, true).apply(); } 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 (!userLearnedDrawer && !fromSavedInstanceState) { this.drawerLayout.openDrawer(getView()); } // Defer code dependent on restoration of previous instance state. this.drawerLayout.post(new Runnable() { @Override public void run() { drawerToggle.syncState(); } }); this.drawerLayout.setDrawerListener(drawerToggle); } @Override public void onConfigurationChanged(Configuration newConfig) { super.onConfigurationChanged(newConfig); // Forward the new configuration the drawer toggle component. drawerToggle.onConfigurationChanged(newConfig); } @Override public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) { // If the drawer is open, show the global app actions in the action bar. See also // showGlobalContextActionBar, which controls the top-left area of the action bar. if (drawerLayout != null && isDrawerOpen()) { inflater.inflate(R.menu.global, menu); showGlobalContextActionBar(); } super.onCreateOptionsMenu(menu, inflater); } @Override public boolean onOptionsItemSelected(MenuItem item) { if (item.getItemId() == android.R.id.home) { // We don't use ActionBarDrawerToggle.onOptionsItemSelected // and instead let the presentation graph control toggles. panePresenter.toggle(); return true; } return super.onOptionsItemSelected(item); } private ActionBar getActionBar() { return getActivity().getActionBar(); } /** * Per the navigation drawer design guidelines, updates the action bar to show the global app * 'context', rather than just what's in the current screen. */ private void showGlobalContextActionBar() { ActionBar actionBar = getActionBar(); actionBar.setDisplayShowTitleEnabled(true); actionBar.setTitle(getActivity().getTitle()); } /** * 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_LEARNED_DRAWER = "navigation_drawer_learned"; private boolean fromSavedInstanceState; private boolean userLearnedDrawer; /** * Helper component that ties the action bar to the navigation drawer. */ private ActionBarDrawerToggle drawerToggle; private DrawerLayout drawerLayout; private ListView drawerListView; private Drawer.PanePresenter panePresenter; }