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
17package com.example.android.animationsdemo;
18
19import android.app.Fragment;
20import android.app.FragmentManager;
21import android.content.Intent;
22import android.os.Bundle;
23import android.support.v13.app.FragmentStatePagerAdapter;
24import android.support.v4.app.FragmentActivity;
25import android.support.v4.app.NavUtils;
26import android.support.v4.view.PagerAdapter;
27import android.support.v4.view.ViewPager;
28import android.view.Menu;
29import android.view.MenuItem;
30
31/**
32 * Demonstrates a "screen-slide" animation using a {@link ViewPager}. Because {@link ViewPager}
33 * automatically plays such an animation when calling {@link ViewPager#setCurrentItem(int)}, there
34 * isn't any animation-specific code in this sample.
35 *
36 * <p>This sample shows a "next" button that advances the user to the next step in a wizard,
37 * animating the current screen out (to the left) and the next screen in (from the right). The
38 * reverse animation is played when the user presses the "previous" button.</p>
39 *
40 * @see ScreenSlidePageFragment
41 */
42public class ScreenSlideActivity extends FragmentActivity {
43    /**
44     * The number of pages (wizard steps) to show in this demo.
45     */
46    private static final int NUM_PAGES = 5;
47
48    /**
49     * The pager widget, which handles animation and allows swiping horizontally to access previous
50     * and next wizard steps.
51     */
52    private ViewPager mPager;
53
54    /**
55     * The pager adapter, which provides the pages to the view pager widget.
56     */
57    private PagerAdapter mPagerAdapter;
58
59    @Override
60    protected void onCreate(Bundle savedInstanceState) {
61        super.onCreate(savedInstanceState);
62        setContentView(R.layout.activity_screen_slide);
63
64        // Instantiate a ViewPager and a PagerAdapter.
65        mPager = (ViewPager) findViewById(R.id.pager);
66        mPagerAdapter = new ScreenSlidePagerAdapter(getFragmentManager());
67        mPager.setAdapter(mPagerAdapter);
68        mPager.setOnPageChangeListener(new ViewPager.SimpleOnPageChangeListener() {
69            @Override
70            public void onPageSelected(int position) {
71                // When changing pages, reset the action bar actions since they are dependent
72                // on which page is currently active. An alternative approach is to have each
73                // fragment expose actions itself (rather than the activity exposing actions),
74                // but for simplicity, the activity provides the actions in this sample.
75                invalidateOptionsMenu();
76            }
77        });
78    }
79
80    @Override
81    public boolean onCreateOptionsMenu(Menu menu) {
82        super.onCreateOptionsMenu(menu);
83        getMenuInflater().inflate(R.menu.activity_screen_slide, menu);
84
85        menu.findItem(R.id.action_previous).setEnabled(mPager.getCurrentItem() > 0);
86
87        // Add either a "next" or "finish" button to the action bar, depending on which page
88        // is currently selected.
89        MenuItem item = menu.add(Menu.NONE, R.id.action_next, Menu.NONE,
90                (mPager.getCurrentItem() == mPagerAdapter.getCount() - 1)
91                        ? R.string.action_finish
92                        : R.string.action_next);
93        item.setShowAsAction(MenuItem.SHOW_AS_ACTION_IF_ROOM | MenuItem.SHOW_AS_ACTION_WITH_TEXT);
94        return true;
95    }
96
97    @Override
98    public boolean onOptionsItemSelected(MenuItem item) {
99        switch (item.getItemId()) {
100            case android.R.id.home:
101                // Navigate "up" the demo structure to the launchpad activity.
102                // See http://developer.android.com/design/patterns/navigation.html for more.
103                NavUtils.navigateUpTo(this, new Intent(this, MainActivity.class));
104                return true;
105
106            case R.id.action_previous:
107                // Go to the previous step in the wizard. If there is no previous step,
108                // setCurrentItem will do nothing.
109                mPager.setCurrentItem(mPager.getCurrentItem() - 1);
110                return true;
111
112            case R.id.action_next:
113                // Advance to the next step in the wizard. If there is no next step, setCurrentItem
114                // will do nothing.
115                mPager.setCurrentItem(mPager.getCurrentItem() + 1);
116                return true;
117        }
118
119        return super.onOptionsItemSelected(item);
120    }
121
122    /**
123     * A simple pager adapter that represents 5 {@link ScreenSlidePageFragment} objects, in
124     * sequence.
125     */
126    private class ScreenSlidePagerAdapter extends FragmentStatePagerAdapter {
127        public ScreenSlidePagerAdapter(FragmentManager fm) {
128            super(fm);
129        }
130
131        @Override
132        public Fragment getItem(int position) {
133            return ScreenSlidePageFragment.create(position);
134        }
135
136        @Override
137        public int getCount() {
138            return NUM_PAGES;
139        }
140    }
141}
142