Java tutorial
/* * Copyright 2012 The Android Open Source Project * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package com.sherlocked.animatingfragments; import android.app.Activity; import android.app.Fragment; import android.app.FragmentManager; import android.content.Intent; import android.os.Bundle; import android.os.Handler; import android.support.v4.app.NavUtils; import android.view.LayoutInflater; import android.view.Menu; import android.view.MenuItem; import android.view.View; import android.view.ViewGroup; import android.widget.TextView; /** * Demonstrates a "card-flip" animation using custom fragment transactions ({@link * android.app.FragmentTransaction#setCustomAnimations(int, int)}). * * <p>This sample shows an "info" action bar button that shows the back of a "card", rotating the * front of the card out and the back of the card in. The reverse animation is played when the user * presses the system Back button or the "photo" action bar button.</p> */ public class CardFlipActivity extends Activity implements FragmentManager.OnBackStackChangedListener { /** * A handler object, used for deferring UI operations. */ private Handler mHandler = new Handler(); /** * Whether or not we're showing the back of the card (otherwise showing the front). */ private boolean mShowingBack = false; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_card_flip); if (savedInstanceState == null) { // If there is no saved instance state, add a fragment representing the // front of the card to this activity. If there is saved instance state, // this fragment will have already been added to the activity. getFragmentManager().beginTransaction().add(R.id.container, new CardFrontFragment()).commit(); } else { mShowingBack = (getFragmentManager().getBackStackEntryCount() > 0); } // Monitor back stack changes to ensure the action bar shows the appropriate // button (either "photo" or "info"). getFragmentManager().addOnBackStackChangedListener(this); } @Override public boolean onCreateOptionsMenu(Menu menu) { super.onCreateOptionsMenu(menu); // Add either a "photo" or "finish" button to the action bar, depending on which page // is currently selected. MenuItem item = menu.add(Menu.NONE, R.id.action_flip, Menu.NONE, mShowingBack ? R.string.action_photo : R.string.action_info); item.setIcon(mShowingBack ? R.drawable.ic_action_photo : R.drawable.ic_action_info); item.setShowAsAction(MenuItem.SHOW_AS_ACTION_IF_ROOM); return true; } @Override public boolean onOptionsItemSelected(MenuItem item) { switch (item.getItemId()) { case android.R.id.home: // Navigate "up" the demo structure to the launchpad activity. // See http://developer.android.com/design/patterns/navigation.html for more. NavUtils.navigateUpTo(this, new Intent(this, MainActivity.class)); return true; case R.id.action_flip: flipCard(); return true; } return super.onOptionsItemSelected(item); } private void flipCard() { if (mShowingBack) { getFragmentManager().popBackStack(); return; } // Flip to the back. mShowingBack = true; // Create and commit a new fragment transaction that adds the fragment for the back of // the card, uses custom animations, and is part of the fragment manager's back stack. getFragmentManager().beginTransaction() // Replace the default fragment animations with animator resources representing // rotations when switching to the back of the card, as well as animator // resources representing rotations when flipping back to the front (e.g. when // the system Back button is pressed). .setCustomAnimations(R.animator.card_flip_right_in, R.animator.card_flip_right_out, R.animator.card_flip_left_in, R.animator.card_flip_left_out) // Replace any fragments currently in the container view with a fragment // representing the next page (indicated by the just-incremented currentPage // variable). .replace(R.id.container, new CardBackFragment()) // Add this transaction to the back stack, allowing users to press Back // to get to the front of the card. .addToBackStack(null) // Commit the transaction. .commit(); // Defer an invalidation of the options menu (on modern devices, the action bar). This // can't be done immediately because the transaction may not yet be committed. Commits // are asynchronous in that they are posted to the main thread's message loop. mHandler.post(new Runnable() { @Override public void run() { invalidateOptionsMenu(); } }); } @Override public void onBackStackChanged() { mShowingBack = (getFragmentManager().getBackStackEntryCount() > 0); // When the back stack changes, invalidate the options menu (action bar). invalidateOptionsMenu(); } /** * A fragment representing the front of the card. */ public static class CardFrontFragment extends Fragment { public CardFrontFragment() { } @Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { return inflater.inflate(R.layout.fragment_card_front, container, false); } } /** * A fragment representing the back of the card. */ public static class CardBackFragment extends Fragment { public CardBackFragment() { } @Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { return inflater.inflate(R.layout.fragment_card_back, container, false); } } }