Android Open Source - prepGRE Navigation Drawer Fragment

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License

The source code is released under:

MIT License

Java Source Code

package com.abhimanbhau.prepgre.ui;
//from  w ww .j  a va2 s  .  co  m
import com.abhimanbhau.prepgre.R;
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.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.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.Toast;

/**
 * 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;

  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());
    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 ArrayAdapter<String>(getActionBar()
        .getThemedContext(), android.R.layout.simple_list_item_1,
        android.R.id.text1, new String[] {
            getString(R.string.title_section1),
            getString(R.string.title_section2),
            getString(R.string.title_section3),
            getString(R.string.title_section4) }));
    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(),
    mDrawerLayout, R.string.navigation_drawer_open,
        R.string.navigation_drawer_close);

    // 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) {
    mCurrentSelectedPosition = position;
    if (mDrawerListView != null) {
      mDrawerListView.setItemChecked(position, true);
    }
    if (mDrawerLayout != null) {
      mDrawerLayout.closeDrawer(mFragmentContainerView);
    }
    if (mCallbacks != null) {
      mCallbacks.onNavigationDrawerItemSelected(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;
    }

    if (item.getItemId() == R.id.action_example) {
      Toast.makeText(getActivity(), "Example action.", Toast.LENGTH_SHORT)
          .show();
      return true;
    }

    return super.onOptionsItemSelected(item);
  }

  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(int position);
  }
}

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