1 /*
2  * Copyright 2013 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *     http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 package com.example.android.navigationdrawerexample;
18 
19 import java.util.Locale;
20 
21 import android.app.Activity;
22 import android.app.Fragment;
23 import android.app.FragmentManager;
24 import android.app.SearchManager;
25 import android.content.Intent;
26 import android.content.res.Configuration;
27 import android.os.Bundle;
28 import android.support.v4.app.ActionBarDrawerToggle;
29 import android.support.v4.view.GravityCompat;
30 import android.support.v4.widget.DrawerLayout;
31 import android.view.LayoutInflater;
32 import android.view.Menu;
33 import android.view.MenuInflater;
34 import android.view.MenuItem;
35 import android.view.View;
36 import android.view.ViewGroup;
37 import android.widget.AdapterView;
38 import android.widget.ArrayAdapter;
39 import android.widget.ImageView;
40 import android.widget.ListView;
41 import android.widget.Toast;
42 
43 /**
44  * This example illustrates a common usage of the DrawerLayout widget
45  * in the Android support library.
46  * <p/>
47  * <p>When a navigation (left) drawer is present, the host activity should detect presses of
48  * the action bar's Up affordance as a signal to open and close the navigation drawer. The
49  * ActionBarDrawerToggle facilitates this behavior.
50  * Items within the drawer should fall into one of two categories:</p>
51  * <p/>
52  * <ul>
53  * <li><strong>View switches</strong>. A view switch follows the same basic policies as
54  * list or tab navigation in that a view switch does not create navigation history.
55  * This pattern should only be used at the root activity of a task, leaving some form
56  * of Up navigation active for activities further down the navigation hierarchy.</li>
57  * <li><strong>Selective Up</strong>. The drawer allows the user to choose an alternate
58  * parent for Up navigation. This allows a user to jump across an app's navigation
59  * hierarchy at will. The application should treat this as it treats Up navigation from
60  * a different task, replacing the current task stack using TaskStackBuilder or similar.
61  * This is the only form of navigation drawer that should be used outside of the root
62  * activity of a task.</li>
63  * </ul>
64  * <p/>
65  * <p>Right side drawers should be used for actions, not navigation. This follows the pattern
66  * established by the Action Bar that navigation should be to the left and actions to the right.
67  * An action should be an operation performed on the current contents of the window,
68  * for example enabling or disabling a data overlay on top of the current content.</p>
69  */
70 public class MainActivity extends Activity {
71     private DrawerLayout mDrawerLayout;
72     private ListView mDrawerList;
73     private ActionBarDrawerToggle mDrawerToggle;
74 
75     private CharSequence mDrawerTitle;
76     private CharSequence mTitle;
77     private String[] mPlanetTitles;
78 
79     @Override
onCreate(Bundle savedInstanceState)80     protected void onCreate(Bundle savedInstanceState) {
81         super.onCreate(savedInstanceState);
82         setContentView(R.layout.activity_main);
83 
84         mTitle = mDrawerTitle = getTitle();
85         mPlanetTitles = getResources().getStringArray(R.array.planets_array);
86         mDrawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout);
87         mDrawerList = (ListView) findViewById(R.id.left_drawer);
88 
89         // set a custom shadow that overlays the main content when the drawer opens
90         mDrawerLayout.setDrawerShadow(R.drawable.drawer_shadow, GravityCompat.START);
91         // set up the drawer's list view with items and click listener
92         mDrawerList.setAdapter(new ArrayAdapter<String>(this,
93                 R.layout.drawer_list_item, mPlanetTitles));
94         mDrawerList.setOnItemClickListener(new DrawerItemClickListener());
95 
96         // enable ActionBar app icon to behave as action to toggle nav drawer
97         getActionBar().setDisplayHomeAsUpEnabled(true);
98         getActionBar().setHomeButtonEnabled(true);
99 
100         // ActionBarDrawerToggle ties together the the proper interactions
101         // between the sliding drawer and the action bar app icon
102         mDrawerToggle = new ActionBarDrawerToggle(
103                 this,                  /* host Activity */
104                 mDrawerLayout,         /* DrawerLayout object */
105                 R.drawable.ic_drawer,  /* nav drawer image to replace 'Up' caret */
106                 R.string.drawer_open,  /* "open drawer" description for accessibility */
107                 R.string.drawer_close  /* "close drawer" description for accessibility */
108                 ) {
109             public void onDrawerClosed(View view) {
110                 getActionBar().setTitle(mTitle);
111                 invalidateOptionsMenu(); // creates call to onPrepareOptionsMenu()
112             }
113 
114             public void onDrawerOpened(View drawerView) {
115                 getActionBar().setTitle(mDrawerTitle);
116                 invalidateOptionsMenu(); // creates call to onPrepareOptionsMenu()
117             }
118         };
119         mDrawerLayout.setDrawerListener(mDrawerToggle);
120 
121         if (savedInstanceState == null) {
122             selectItem(0);
123         }
124     }
125 
126     @Override
onCreateOptionsMenu(Menu menu)127     public boolean onCreateOptionsMenu(Menu menu) {
128         MenuInflater inflater = getMenuInflater();
129         inflater.inflate(R.menu.main, menu);
130         return super.onCreateOptionsMenu(menu);
131     }
132 
133     /* Called whenever we call invalidateOptionsMenu() */
134     @Override
onPrepareOptionsMenu(Menu menu)135     public boolean onPrepareOptionsMenu(Menu menu) {
136         // If the nav drawer is open, hide action items related to the content view
137         boolean drawerOpen = mDrawerLayout.isDrawerOpen(mDrawerList);
138         menu.findItem(R.id.action_websearch).setVisible(!drawerOpen);
139         return super.onPrepareOptionsMenu(menu);
140     }
141 
142     @Override
onOptionsItemSelected(MenuItem item)143     public boolean onOptionsItemSelected(MenuItem item) {
144          // The action bar home/up action should open or close the drawer.
145          // ActionBarDrawerToggle will take care of this.
146         if (mDrawerToggle.onOptionsItemSelected(item)) {
147             return true;
148         }
149         // Handle action buttons
150         switch(item.getItemId()) {
151         case R.id.action_websearch:
152             // create intent to perform web search for this planet
153             Intent intent = new Intent(Intent.ACTION_WEB_SEARCH);
154             intent.putExtra(SearchManager.QUERY, getActionBar().getTitle());
155             // catch event that there's no activity to handle intent
156             if (intent.resolveActivity(getPackageManager()) != null) {
157                 startActivity(intent);
158             } else {
159                 Toast.makeText(this, R.string.app_not_available, Toast.LENGTH_LONG).show();
160             }
161             return true;
162         default:
163             return super.onOptionsItemSelected(item);
164         }
165     }
166 
167     /* The click listner for ListView in the navigation drawer */
168     private class DrawerItemClickListener implements ListView.OnItemClickListener {
169         @Override
onItemClick(AdapterView<?> parent, View view, int position, long id)170         public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
171             selectItem(position);
172         }
173     }
174 
selectItem(int position)175     private void selectItem(int position) {
176         // update the main content by replacing fragments
177         Fragment fragment = new PlanetFragment();
178         Bundle args = new Bundle();
179         args.putInt(PlanetFragment.ARG_PLANET_NUMBER, position);
180         fragment.setArguments(args);
181 
182         FragmentManager fragmentManager = getFragmentManager();
183         fragmentManager.beginTransaction().replace(R.id.content_frame, fragment).commit();
184 
185         // update selected item and title, then close the drawer
186         mDrawerList.setItemChecked(position, true);
187         setTitle(mPlanetTitles[position]);
188         mDrawerLayout.closeDrawer(mDrawerList);
189     }
190 
191     @Override
setTitle(CharSequence title)192     public void setTitle(CharSequence title) {
193         mTitle = title;
194         getActionBar().setTitle(mTitle);
195     }
196 
197     /**
198      * When using the ActionBarDrawerToggle, you must call it during
199      * onPostCreate() and onConfigurationChanged()...
200      */
201 
202     @Override
onPostCreate(Bundle savedInstanceState)203     protected void onPostCreate(Bundle savedInstanceState) {
204         super.onPostCreate(savedInstanceState);
205         // Sync the toggle state after onRestoreInstanceState has occurred.
206         mDrawerToggle.syncState();
207     }
208 
209     @Override
onConfigurationChanged(Configuration newConfig)210     public void onConfigurationChanged(Configuration newConfig) {
211         super.onConfigurationChanged(newConfig);
212         // Pass any configuration change to the drawer toggls
213         mDrawerToggle.onConfigurationChanged(newConfig);
214     }
215 
216     /**
217      * Fragment that appears in the "content_frame", shows a planet
218      */
219     public static class PlanetFragment extends Fragment {
220         public static final String ARG_PLANET_NUMBER = "planet_number";
221 
PlanetFragment()222         public PlanetFragment() {
223             // Empty constructor required for fragment subclasses
224         }
225 
226         @Override
onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)227         public View onCreateView(LayoutInflater inflater, ViewGroup container,
228                 Bundle savedInstanceState) {
229             View rootView = inflater.inflate(R.layout.fragment_planet, container, false);
230             int i = getArguments().getInt(ARG_PLANET_NUMBER);
231             String planet = getResources().getStringArray(R.array.planets_array)[i];
232 
233             int imageId = getResources().getIdentifier(planet.toLowerCase(Locale.getDefault()),
234                             "drawable", getActivity().getPackageName());
235             ((ImageView) rootView.findViewById(R.id.image)).setImageResource(imageId);
236             getActivity().setTitle(planet);
237             return rootView;
238         }
239     }
240 }