Java tutorial
/** * Copyright 2014 Carl-Philipp Harmant * * 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 fr.cph.chicago.fragment.drawer; import java.util.ArrayList; import java.util.List; 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.os.Handler; 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.Menu; import android.view.MenuInflater; import android.view.MenuItem; import android.view.View; import android.view.ViewGroup; import android.widget.AdapterView; import android.widget.ListView; import fr.cph.chicago.R; /** * 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_LEARNED_DRAWER = "navigation_drawer_learned"; /** * A pointer to the current callback instance (the Activity). */ private NavigationDrawerCallbacks mCallbacks; /** * Helper component that ties the action bar to the navigation drawer. */ private ActionBarDrawerToggle mDrawerToggle; /** The drawer layout **/ private DrawerLayout mDrawerLayout; /** the drawer list view **/ private ListView mDrawerListView; /** The fragment container **/ private View mFragmentContainerView; /** The current selected position **/ private int mCurrentSelectedPosition = 0; /** The saved instance **/ private boolean mFromSavedInstanceState; /** The user learned drawer **/ private boolean mUserLearnedDrawer; /** The pending runnable thread **/ private Runnable mPendingRunnable; @Override public final void onCreate(final 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()); mUserLearnedDrawer = sp.getBoolean(PREF_USER_LEARNED_DRAWER, false); if (savedInstanceState != null) { mCurrentSelectedPosition = savedInstanceState.getInt(STATE_SELECTED_POSITION); mFromSavedInstanceState = true; } // Select either the default item (0) or the last selected item. selectItem(mCurrentSelectedPosition, false); // Indicate that this fragment would like to influence the set of actions in the action bar. setHasOptionsMenu(true); } @Override public final View onCreateView(final LayoutInflater inflater, final ViewGroup container, final Bundle savedInstanceState) { mDrawerListView = (ListView) inflater.inflate(R.layout.fragment_navigation_drawer, container, false); mDrawerListView.setOnItemClickListener(new AdapterView.OnItemClickListener() { @Override public void onItemClick(AdapterView<?> parent, View view, int position, long id) { selectItem(position, false); } }); List<DrawerItem> drawerItems = new ArrayList<DrawerItem>(); DrawerItem item1 = new DrawerItem(getString(R.string.favorites), R.drawable.ic_action_favorite); DrawerItem item2 = new DrawerItem(getString(R.string.train), R.drawable.ic_action_train); DrawerItem item3 = new DrawerItem(getString(R.string.bus), R.drawable.ic_action_bus); DrawerItem item4 = new DrawerItem(getString(R.string.divvy), R.drawable.ic_action_bike); DrawerItem item5 = new DrawerItem(getString(R.string.nearby), R.drawable.ic_action_nearby); DrawerItem item6 = new DrawerItem(getString(R.string.alerts), R.drawable.ic_dialog_alert); DrawerItem item7 = new DrawerItem(getString(R.string.map), R.drawable.ic_action_map); DrawerItem item8 = new DrawerItem(getString(R.string.settings), R.drawable.ic_action_settings); drawerItems.add(item1); drawerItems.add(item2); drawerItems.add(item3); drawerItems.add(item4); drawerItems.add(item5); drawerItems.add(item6); drawerItems.add(item7); drawerItems.add(item8); CustomDrawerAdapter ada = new CustomDrawerAdapter(getActivity(), R.layout.custom_drawer_item, drawerItems); mDrawerListView.setAdapter(ada); mDrawerListView.setItemChecked(mCurrentSelectedPosition, true); mDrawerListView.setSelector(R.drawable.drawer_selector); return mDrawerListView; } public final boolean isDrawerOpen() { return mDrawerLayout != null && mDrawerLayout.isDrawerOpen(mFragmentContainerView); } /** * 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 final void setUp(final int fragmentId, final DrawerLayout drawerLayout) { mFragmentContainerView = getActivity().findViewById(fragmentId); mDrawerLayout = drawerLayout; // set a custom shadow that overlays the main content when the drawer opens mDrawerLayout.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. mDrawerToggle = new ActionBarDrawerToggle(getActivity(), /* host Activity */ mDrawerLayout, /* 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; } if (mPendingRunnable != null) { Handler mHandler = new Handler(); mHandler.post(mPendingRunnable); mPendingRunnable = null; } getActivity().invalidateOptionsMenu(); // calls onPrepareOptionsMenu() } @Override public void onDrawerOpened(View drawerView) { super.onDrawerOpened(drawerView); if (!isAdded()) { return; } if (!mUserLearnedDrawer) { // The user manually opened the drawer; store this flag to prevent auto-showing // the navigation drawer automatically in the future. mUserLearnedDrawer = 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 (!mUserLearnedDrawer && !mFromSavedInstanceState) { mDrawerLayout.openDrawer(mFragmentContainerView); } // Defer code dependent on restoration of previous instance state. mDrawerLayout.post(new Runnable() { @Override public void run() { mDrawerToggle.syncState(); } }); mDrawerLayout.setDrawerListener(mDrawerToggle); } /** * Select item * * @param position * the position * @param backPressed * if back pressed */ public void selectItem(final int position, boolean backPressed) { mCurrentSelectedPosition = position; mPendingRunnable = new Runnable() { @Override public void run() { if (mCallbacks != null) { mCallbacks.onNavigationDrawerItemSelected(position); } } }; if (backPressed) { Handler mHandler = new Handler(); mHandler.post(mPendingRunnable); mPendingRunnable = null; } if (mDrawerListView != null) { mDrawerListView.setItemChecked(position, true); } if (mDrawerLayout != null) { mDrawerLayout.closeDrawer(mFragmentContainerView); } else { mCallbacks.onNavigationDrawerItemSelected(position); } // if (mCallbacks != null) { // mCallbacks.onNavigationDrawerItemSelected(position); // } } @Override public final void onAttach(final Activity activity) { super.onAttach(activity); try { mCallbacks = (NavigationDrawerCallbacks) activity; } catch (ClassCastException e) { throw new ClassCastException("Activity must implement NavigationDrawerCallbacks."); } } @Override public final void onDetach() { super.onDetach(); mCallbacks = null; } @Override public final void onSaveInstanceState(final Bundle outState) { super.onSaveInstanceState(outState); outState.putInt(STATE_SELECTED_POSITION, mCurrentSelectedPosition); } @Override public final void onConfigurationChanged(final Configuration newConfig) { super.onConfigurationChanged(newConfig); // Forward the new configuration the drawer toggle component. mDrawerToggle.onConfigurationChanged(newConfig); } @Override public final void onCreateOptionsMenu(final Menu menu, final 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 (mDrawerLayout != null && isDrawerOpen()) { inflater.inflate(R.menu.empty, menu); showGlobalContextActionBar(); } super.onCreateOptionsMenu(menu, inflater); } @Override public final boolean onOptionsItemSelected(final MenuItem item) { if (mDrawerToggle.onOptionsItemSelected(item)) { return true; } return super.onOptionsItemSelected(item); } /** * 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 final void showGlobalContextActionBar() { ActionBar actionBar = getActionBar(); actionBar.setDisplayShowTitleEnabled(true); actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_STANDARD); actionBar.setTitle(R.string.app_name); } /** * Get action bar * * @return the action bar */ private final 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); } }