Java tutorial
/* * Copyright (C) 2015 Victor Apoyan. * * 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.armtimes.drawer; import android.graphics.drawable.ColorDrawable; import android.support.v7.app.ActionBarActivity; import android.app.Activity; import android.support.v7.app.ActionBar; import android.support.v4.app.Fragment; import android.support.v4.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.text.Html; 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 com.armtimes.R; import java.util.ArrayList; import java.util.List; /** * 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 { /** * List of Fragments used in the application */ private static List<Fragment> mFragments = new ArrayList<Fragment>(); static { mFragments.add(null); mFragments.add(new CommonFragment.PoliticsFragment()); mFragments.add(new CommonFragment.EconomyFragment()); mFragments.add(new CommonFragment.WorldFragment()); mFragments.add(new CommonFragment.LawFragment()); mFragments.add(new CommonFragment.SocietyFragment()); mFragments.add(new CommonFragment.CultureFragment()); mFragments.add(new CommonFragment.SportFragment()); mFragments.add(null); mFragments.add(null); mFragments.add(null); } /** * 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 callbacks instance (the Activity). */ private NavigationDrawerCallbacks mCallbacks; /** * List of items which are shown in the navigation drawable. */ private List<NavigationDrawerTitleItem> mDrawerList; /** * Helper component that ties the action bar to the navigation drawer. */ private ActionBarDrawerToggle mDrawerToggle; private DrawerLayout mDrawerLayout; private ListView mDrawerListView; private View mFragmentContainerView; private int mCurrentSelectedPosition = 1; private boolean mFromSavedInstanceState; private boolean mUserLearnedDrawer; public NavigationDrawerFragment() { } @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); // Create new drawer list and add items to it. mDrawerList = new ArrayList<>(); mDrawerList.add(new NavigationDrawerTitleItem(getActivity().getString(R.string.sections))); mDrawerList.add(new NavigationDrawerSubtitleItem(getActivity().getString(R.string.fr_name_politics), R.drawable.ic_politics)); mDrawerList.add(new NavigationDrawerSubtitleItem(getActivity().getString(R.string.fr_name_economy), R.drawable.ic_economy)); mDrawerList.add(new NavigationDrawerSubtitleItem(getActivity().getString(R.string.fr_name_world), R.drawable.ic_world)); mDrawerList.add( new NavigationDrawerSubtitleItem(getActivity().getString(R.string.fr_name_law), R.drawable.ic_law)); mDrawerList.add(new NavigationDrawerSubtitleItem(getActivity().getString(R.string.fr_name_society), R.drawable.ic_society)); mDrawerList.add(new NavigationDrawerSubtitleItem(getActivity().getString(R.string.fr_name_culture), R.drawable.ic_culture)); mDrawerList.add(new NavigationDrawerSubtitleItem(getActivity().getString(R.string.fr_name_sport), R.drawable.ic_sport)); mDrawerList.add(new NavigationDrawerTitleItem(getActivity().getString(R.string.other))); mDrawerList.add(new NavigationDrawerSubtitleItem(getActivity().getString(R.string.settings), R.drawable.ic_settings)); mDrawerList.add( new NavigationDrawerSubtitleItem(getActivity().getString(R.string.about_us), R.drawable.ic_info)); // 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); } @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) { 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); } }); mDrawerListView.setAdapter( new NavigationDrawerAdapter(getActivity(), R.layout.row_single_drawer_item, mDrawerList)); mDrawerListView.setItemChecked(mCurrentSelectedPosition, true); return mDrawerListView; } public 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 void setUp(int fragmentId, 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; } getActivity().supportInvalidateOptionsMenu(); // 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().supportInvalidateOptionsMenu(); // 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); } private void selectItem(int position) { // Special case for "Settings" and "About Us" items in // navigation drawer, this two items must not be selected. if (position == 10 || position == 9) { if (mDrawerListView != null) { mDrawerListView.setItemChecked(mCurrentSelectedPosition, true); mDrawerListView.setSelection(mCurrentSelectedPosition); } if (mDrawerLayout != null) mDrawerLayout.closeDrawer(mFragmentContainerView); if (mCallbacks != null) mCallbacks.onNavigationDrawerItemSelected(null, position); return; } mCurrentSelectedPosition = position; if (mDrawerListView != null) { mDrawerListView.setItemChecked(position, true); } if (mDrawerLayout != null) { mDrawerLayout.closeDrawer(mFragmentContainerView); } if (mCallbacks != null) { mCallbacks.onNavigationDrawerItemSelected(mFragments.get(position), position); } } @Override public void onAttach(Activity activity) { super.onAttach(activity); try { mCallbacks = (NavigationDrawerCallbacks) activity; } catch (ClassCastException e) { throw new ClassCastException("Activity must implement NavigationDrawerCallbacks."); } } @Override public void onDetach() { super.onDetach(); mCallbacks = null; } @Override public void onSaveInstanceState(Bundle outState) { super.onSaveInstanceState(outState); outState.putInt(STATE_SELECTED_POSITION, mCurrentSelectedPosition); } @Override public void onConfigurationChanged(Configuration newConfig) { super.onConfigurationChanged(newConfig); // Forward the new configuration the drawer toggle component. mDrawerToggle.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 (mDrawerLayout != null && isDrawerOpen()) { inflater.inflate(R.menu.global, menu); showGlobalContextActionBar(); } super.onCreateOptionsMenu(menu, inflater); } @Override public boolean onOptionsItemSelected(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 void showGlobalContextActionBar() { ActionBar actionBar = getActionBar(); actionBar.setDisplayShowTitleEnabled(true); actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_STANDARD); actionBar.setBackgroundDrawable(new ColorDrawable(0xFFFA294C)); actionBar.setTitle(Html.fromHtml("<small>" + getActivity().getString(R.string.app_name) + "</small>")); } private ActionBar getActionBar() { return ((ActionBarActivity) getActivity()).getSupportActionBar(); } /** * 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(Fragment fragment, int position); } }