1 /*
2  * Copyright 2012 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.animationsdemo;
18 
19 import android.app.Activity;
20 import android.app.Fragment;
21 import android.app.FragmentManager;
22 import android.content.Intent;
23 import android.os.Bundle;
24 import android.os.Handler;
25 import android.support.v4.app.NavUtils;
26 import android.view.LayoutInflater;
27 import android.view.Menu;
28 import android.view.MenuItem;
29 import android.view.View;
30 import android.view.ViewGroup;
31 import android.widget.TextView;
32 
33 /**
34  * Demonstrates a "card-flip" animation using custom fragment transactions ({@link
35  * android.app.FragmentTransaction#setCustomAnimations(int, int)}).
36  *
37  * <p>This sample shows an "info" action bar button that shows the back of a "card", rotating the
38  * front of the card out and the back of the card in. The reverse animation is played when the user
39  * presses the system Back button or the "photo" action bar button.</p>
40  */
41 public class CardFlipActivity extends Activity
42         implements FragmentManager.OnBackStackChangedListener {
43     /**
44      * A handler object, used for deferring UI operations.
45      */
46     private Handler mHandler = new Handler();
47 
48     /**
49      * Whether or not we're showing the back of the card (otherwise showing the front).
50      */
51     private boolean mShowingBack = false;
52 
53     @Override
onCreate(Bundle savedInstanceState)54     protected void onCreate(Bundle savedInstanceState) {
55         super.onCreate(savedInstanceState);
56         setContentView(R.layout.activity_card_flip);
57 
58         if (savedInstanceState == null) {
59             // If there is no saved instance state, add a fragment representing the
60             // front of the card to this activity. If there is saved instance state,
61             // this fragment will have already been added to the activity.
62             getFragmentManager()
63                     .beginTransaction()
64                     .add(R.id.container, new CardFrontFragment())
65                     .commit();
66         } else {
67             mShowingBack = (getFragmentManager().getBackStackEntryCount() > 0);
68         }
69 
70         // Monitor back stack changes to ensure the action bar shows the appropriate
71         // button (either "photo" or "info").
72         getFragmentManager().addOnBackStackChangedListener(this);
73     }
74 
75     @Override
onCreateOptionsMenu(Menu menu)76     public boolean onCreateOptionsMenu(Menu menu) {
77         super.onCreateOptionsMenu(menu);
78 
79         // Add either a "photo" or "finish" button to the action bar, depending on which page
80         // is currently selected.
81         MenuItem item = menu.add(Menu.NONE, R.id.action_flip, Menu.NONE,
82                 mShowingBack
83                         ? R.string.action_photo
84                         : R.string.action_info);
85         item.setIcon(mShowingBack
86                 ? R.drawable.ic_action_photo
87                 : R.drawable.ic_action_info);
88         item.setShowAsAction(MenuItem.SHOW_AS_ACTION_IF_ROOM);
89         return true;
90     }
91 
92     @Override
onOptionsItemSelected(MenuItem item)93     public boolean onOptionsItemSelected(MenuItem item) {
94         switch (item.getItemId()) {
95             case android.R.id.home:
96                 // Navigate "up" the demo structure to the launchpad activity.
97                 // See http://developer.android.com/design/patterns/navigation.html for more.
98                 NavUtils.navigateUpTo(this, new Intent(this, MainActivity.class));
99                 return true;
100 
101             case R.id.action_flip:
102                 flipCard();
103                 return true;
104         }
105 
106         return super.onOptionsItemSelected(item);
107     }
108 
flipCard()109     private void flipCard() {
110         if (mShowingBack) {
111             getFragmentManager().popBackStack();
112             return;
113         }
114 
115         // Flip to the back.
116 
117         mShowingBack = true;
118 
119         // Create and commit a new fragment transaction that adds the fragment for the back of
120         // the card, uses custom animations, and is part of the fragment manager's back stack.
121 
122         getFragmentManager()
123                 .beginTransaction()
124 
125                 // Replace the default fragment animations with animator resources representing
126                 // rotations when switching to the back of the card, as well as animator
127                 // resources representing rotations when flipping back to the front (e.g. when
128                 // the system Back button is pressed).
129                 .setCustomAnimations(
130                         R.animator.card_flip_right_in, R.animator.card_flip_right_out,
131                         R.animator.card_flip_left_in, R.animator.card_flip_left_out)
132 
133                 // Replace any fragments currently in the container view with a fragment
134                 // representing the next page (indicated by the just-incremented currentPage
135                 // variable).
136                 .replace(R.id.container, new CardBackFragment())
137 
138                 // Add this transaction to the back stack, allowing users to press Back
139                 // to get to the front of the card.
140                 .addToBackStack(null)
141 
142                 // Commit the transaction.
143                 .commit();
144 
145         // Defer an invalidation of the options menu (on modern devices, the action bar). This
146         // can't be done immediately because the transaction may not yet be committed. Commits
147         // are asynchronous in that they are posted to the main thread's message loop.
148         mHandler.post(new Runnable() {
149             @Override
150             public void run() {
151                 invalidateOptionsMenu();
152             }
153         });
154     }
155 
156     @Override
onBackStackChanged()157     public void onBackStackChanged() {
158         mShowingBack = (getFragmentManager().getBackStackEntryCount() > 0);
159 
160         // When the back stack changes, invalidate the options menu (action bar).
161         invalidateOptionsMenu();
162     }
163 
164     /**
165      * A fragment representing the front of the card.
166      */
167     public static class CardFrontFragment extends Fragment {
CardFrontFragment()168         public CardFrontFragment() {
169         }
170 
171         @Override
onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)172         public View onCreateView(LayoutInflater inflater, ViewGroup container,
173                 Bundle savedInstanceState) {
174             return inflater.inflate(R.layout.fragment_card_front, container, false);
175         }
176     }
177 
178     /**
179      * A fragment representing the back of the card.
180      */
181     public static class CardBackFragment extends Fragment {
CardBackFragment()182         public CardBackFragment() {
183         }
184 
185         @Override
onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)186         public View onCreateView(LayoutInflater inflater, ViewGroup container,
187                 Bundle savedInstanceState) {
188             return inflater.inflate(R.layout.fragment_card_back, container, false);
189         }
190     }
191 }
192