Java tutorial
/* * Infinity Browser 2014 Matt Blackman * * 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 2 * 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, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */ package blackman.matt.infinitebrowser; import android.app.Activity; import android.app.ActionBar; import android.app.Fragment; import android.app.FragmentManager; import android.app.FragmentTransaction; import android.database.Cursor; 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.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.LinearLayout; import android.widget.ListView; import android.widget.SimpleCursorAdapter; import android.widget.TextView; import blackman.matt.board.Board; import blackman.matt.boardlist.BoardListDatabase; /** * 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 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 int mCurrentSelectedPosition = 0; private boolean mFromSavedInstanceState; private boolean mUserLearnedDrawer; /** * Auto-generated constructor full of nothing. */ public NavigationDrawerFragment() { } /** * Called when the fragment is first created on the activity. Gets the arguments. * * @param savedInstanceState the instance state of the activity. */ @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()); 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); } /** * Called when the fragments is created in the activity. * * @param savedInstanceState the instance state of the activity. */ @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); } /** * Closes the navigation drawer. */ void closeDrawer() { mDrawerLayout.closeDrawers(); } /** * Called when the fragments view is being created. Handled inflating the view and assigning * values. * * @param inflater inflater sent in from parent activity. * @param container The container that the fragment will go in. * @param savedInstanceState the instance state of the activity. * @return returns this fragments newly created view. */ @Override public View onCreateView(LayoutInflater inflater, final ViewGroup container, Bundle savedInstanceState) { LinearLayout drawerview = (LinearLayout) inflater.inflate(R.layout.fragment_navigation_drawer, container, false); mDrawerListView = (ListView) drawerview.findViewById(R.id.navigation_drawer_listview); mDrawerListView.setOnItemClickListener(new AdapterView.OnItemClickListener() { @Override public void onItemClick(AdapterView<?> parent, View view, int position, long id) { selectItem(position); } }); SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(getActivity()); Boolean ageAccept = preferences.getBoolean("age_guard_accept", false); if (ageAccept) { setUpListAdapter(); } mDrawerListView.setItemChecked(mCurrentSelectedPosition, true); return drawerview; } /** * Sets up the list adapter for the list of boards the user is following. */ private void setUpListAdapter() { BoardListDatabase boardListDB; Cursor cursor; boardListDB = new BoardListDatabase(getActivity()); cursor = boardListDB.getFavoritedBoards(); String[] from = new String[] { "boardlink" }; int[] to = new int[] { R.id.text }; SimpleCursorAdapter cursorAdapter = new SimpleCursorAdapter(mDrawerListView.getContext(), R.layout.drawer_item, cursor, from, to, 0) { @Override public View getView(int position, View convertView, ViewGroup parent) { View view = super.getView(position, convertView, parent); if (position % 2 == 1) { view.setBackgroundColor(getActivity().getResources().getColor(R.color.row_color_2)); } return view; } }; mDrawerListView.setAdapter(cursorAdapter); boardListDB.close(); } /** * Returns true or false value on if the drawer is open. * * @return If the drawer is open. */ 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 */ ) { /** * Handles the drawer being closed. * * @param drawerView The drawer being closed. */ @Override public void onDrawerClosed(View drawerView) { super.onDrawerClosed(drawerView); if (!isAdded()) { return; } getActivity().invalidateOptionsMenu(); // calls onPrepareOptionsMenu() } /** * Handles the drawer being opened. * * @param drawerView The drawer being opened. */ @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(); } setUpListAdapter(); getActivity().invalidateOptionsMenu(); // calls onPrepareOptionsMenu() } }; mDrawerListView.setOnItemClickListener(new AdapterView.OnItemClickListener() { @Override public void onItemClick(AdapterView<?> parent, View view, int position, long id) { String boardRoot = "/tech/"; if (view instanceof TextView) { boardRoot = ((TextView) view).getText().toString(); } FragmentManager fragmentManager = getFragmentManager(); FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction(); Board newBoard = Board.newInstance(boardRoot); fragmentTransaction.replace(R.id.container, newBoard, boardRoot); fragmentTransaction.addToBackStack(null); fragmentTransaction.commit(); closeDrawer(); } }); // 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); } /** * Handles an item being selected on the drawers list view. * * @param position Position of the item being selected. Starts at 1. */ private void selectItem(int position) { mCurrentSelectedPosition = position; if (mDrawerListView != null) { mDrawerListView.setItemChecked(position, true); } if (mDrawerLayout != null) { mDrawerLayout.closeDrawer(mFragmentContainerView); } if (mCallbacks != null) { mCallbacks.onNavigationDrawerItemSelected(position); } } /** * Called when the parent activity attached to this newly created fragment and checks * if the fragment interaction listener has be implemented by the activity. * * @param activity the parent activity of this fragment. */ @Override public void onAttach(Activity activity) { super.onAttach(activity); try { mCallbacks = (NavigationDrawerCallbacks) activity; } catch (ClassCastException e) { throw new ClassCastException("Activity must implement NavigationDrawerCallbacks."); } } /** * After the fragment has run it's course and much be removed from the activity this * is called. */ @Override public void onDetach() { super.onDetach(); mCallbacks = null; } /** * Something to communicate with the parent of this drawer. * * @param outState State of something. */ @Override public void onSaveInstanceState(Bundle outState) { super.onSaveInstanceState(outState); outState.putInt(STATE_SELECTED_POSITION, mCurrentSelectedPosition); } /** * Handles the configuration of the drawer being changed. * * @param newConfig The new configuration to be set to. */ @Override public void onConfigurationChanged(Configuration newConfig) { super.onConfigurationChanged(newConfig); // Forward the new configuration the drawer toggle component. mDrawerToggle.onConfigurationChanged(newConfig); } /** * Called when the options menu is created in the drawer. * * @param menu The menu being added in. * @param inflater The context of the utility that will inflate the view. */ @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.board_browser, menu); showGlobalContextActionBar(); } super.onCreateOptionsMenu(menu, inflater); } /** * Called when an item in the options menu is selected. Handles the change. * * @param item The item that was selected. * @return If the item was selected or not. */ @Override public boolean onOptionsItemSelected(MenuItem item) { return mDrawerToggle.onOptionsItemSelected(item) || 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.setTitle(R.string.app_name); } /** * Gets the action bar of the main activity. * * @return The action bar of the main activity. */ 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); } }