Java tutorial
/* * Copyright (C) 2014 Fastboot Mobile, LLC. * * This program 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 3 of * the License, or (at your option) any later version. * * This program 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 this program; * if not, see <http://www.gnu.org/licenses>. */ package com.fastbootmobile.encore.app.fragments; import android.app.ActionBar; import android.app.Activity; import android.content.SharedPreferences; import android.content.res.Configuration; import android.graphics.Typeface; import android.os.Bundle; import android.os.Handler; import android.preference.PreferenceManager; import android.support.v4.app.Fragment; import android.support.v4.view.GravityCompat; import android.support.v4.widget.DrawerLayout; import android.support.v7.app.ActionBarDrawerToggle; 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 android.widget.TextView; import com.fastbootmobile.encore.app.MainActivity; import com.fastbootmobile.encore.app.R; import com.fastbootmobile.encore.app.adapters.NavDrawerAdapter; /** * 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 { private static final String TAG = "NavigationDrawerFragment"; /** * 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; /** * Helper component that ties the action bar to the navigation drawer. */ private ActionBarDrawerToggle mDrawerToggle; private DrawerLayout mDrawerLayout; private ListView mDrawerListView; private View mFragmentContainerView; private TextView mPreviousItem; private Handler mHandler; private static Typeface sUnselectedTypeface; private static Typeface sSelectedTypeface; private int mCurrentSelectedPosition = 0; private boolean mFromSavedInstanceState; private boolean mUserLearnedDrawer; public NavigationDrawerFragment() { sUnselectedTypeface = Typeface.create("sans-serif", 0); sSelectedTypeface = Typeface.create("sans-serif", Typeface.BOLD); } @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); mHandler = new Handler(); // 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, savedInstanceState == null); } @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 NavDrawerAdapter()); mDrawerListView.setItemChecked(mCurrentSelectedPosition, true); mDrawerListView.post(new Runnable() { @Override public void run() { selectItem(mCurrentSelectedPosition, (mCurrentSelectedPosition + 1) < MainActivity.SECTION_DRIVE_MODE); } }); return mDrawerListView; } public void setDrawerIndicatorEnabled(boolean enabled) { mDrawerToggle.setDrawerIndicatorEnabled(enabled); } public boolean isDrawerOpen() { return mDrawerLayout != null && mDrawerLayout.isDrawerOpen(mFragmentContainerView); } @Override public void onConfigurationChanged(Configuration newConfig) { super.onConfigurationChanged(newConfig); // Forward the new configuration the drawer toggle component. mDrawerToggle.onConfigurationChanged(newConfig); } /** * 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); // 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 */ ((MainActivity) getActivity()).getToolbar(), 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; } 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() } }; mDrawerToggle.setToolbarNavigationClickListener(new View.OnClickListener() { @Override public void onClick(View v) { if (!mDrawerToggle.isDrawerIndicatorEnabled()) { getActivity().onBackPressed(); } } }); // 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); } public void openDrawer() { if (mDrawerLayout != null) { mDrawerLayout.openDrawer(mFragmentContainerView); } } public void closeDrawer() { if (mDrawerLayout != null) { mDrawerLayout.closeDrawer(mFragmentContainerView); } } public void selectItem(final int position) { selectItem(position, true); } private void selectItem(final int position, boolean switchToFragment) { // Don't select special actions if (position + 1 < MainActivity.SECTION_DRIVE_MODE) { mCurrentSelectedPosition = position; if (mDrawerListView != null) { ((NavDrawerAdapter) mDrawerListView.getAdapter()).setActive(position); } } if (switchToFragment) { if (mDrawerListView != null) { mDrawerListView.setItemChecked(position, true); } if (mDrawerLayout != null) { mDrawerLayout.closeDrawer(mFragmentContainerView); } mHandler.post(new Runnable() { @Override public void run() { if (mCallbacks != null && mCallbacks.onNavigationDrawerItemSelected(position)) { if (mPreviousItem != null) { mPreviousItem.setTypeface(sUnselectedTypeface); } View view = mDrawerListView.getChildAt(mCurrentSelectedPosition); if (view != null) { TextView tv = (TextView) view.findViewById(android.R.id.text1); tv.setTypeface(sSelectedTypeface); mPreviousItem = tv; } } } }); } } @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 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); } super.onCreateOptionsMenu(menu, inflater); } @Override public boolean onOptionsItemSelected(MenuItem item) { if (mDrawerToggle.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. */ boolean onNavigationDrawerItemSelected(int position); } }