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      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
     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
     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
     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 
    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
    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 {
    168         public CardFrontFragment() {
    169         }
    170 
    171         @Override
    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 {
    182         public CardBackFragment() {
    183         }
    184 
    185         @Override
    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