1/*
2 * Copyright (C) 2011 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 */
16package com.example.android.supportv13.app;
17
18import java.util.ArrayList;
19
20import com.example.android.supportv13.R;
21
22import android.app.ActionBar;
23import android.app.ActionBar.Tab;
24import android.app.Activity;
25import android.app.Fragment;
26import android.app.FragmentTransaction;
27import android.content.Context;
28import android.os.Bundle;
29import android.support.v13.app.FragmentPagerAdapter;
30import android.support.v4.view.ViewPager;
31
32/**
33 * This demonstrates the use of action bar tabs and how they interact
34 * with other action bar features.
35 */
36//BEGIN_INCLUDE(complete)
37public class ActionBarTabsPager extends Activity {
38    ViewPager mViewPager;
39    TabsAdapter mTabsAdapter;
40
41    @Override
42    protected void onCreate(Bundle savedInstanceState) {
43        super.onCreate(savedInstanceState);
44
45        mViewPager = new ViewPager(this);
46        mViewPager.setId(R.id.pager);
47        setContentView(mViewPager);
48
49        final ActionBar bar = getActionBar();
50        bar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
51        bar.setDisplayOptions(0, ActionBar.DISPLAY_SHOW_TITLE);
52
53        mTabsAdapter = new TabsAdapter(this, mViewPager);
54        mTabsAdapter.addTab(bar.newTab().setText("Simple"),
55                CountingFragment.class, null);
56        mTabsAdapter.addTab(bar.newTab().setText("List"),
57                FragmentPagerSupport.ArrayListFragment.class, null);
58        mTabsAdapter.addTab(bar.newTab().setText("Cursor"),
59                CursorFragment.class, null);
60
61        if (savedInstanceState != null) {
62            bar.setSelectedNavigationItem(savedInstanceState.getInt("tab", 0));
63        }
64    }
65
66    @Override
67    protected void onSaveInstanceState(Bundle outState) {
68        super.onSaveInstanceState(outState);
69        outState.putInt("tab", getActionBar().getSelectedNavigationIndex());
70    }
71
72    /**
73     * This is a helper class that implements the management of tabs and all
74     * details of connecting a ViewPager with associated TabHost.  It relies on a
75     * trick.  Normally a tab host has a simple API for supplying a View or
76     * Intent that each tab will show.  This is not sufficient for switching
77     * between pages.  So instead we make the content part of the tab host
78     * 0dp high (it is not shown) and the TabsAdapter supplies its own dummy
79     * view to show as the tab content.  It listens to changes in tabs, and takes
80     * care of switch to the correct paged in the ViewPager whenever the selected
81     * tab changes.
82     */
83    public static class TabsAdapter extends FragmentPagerAdapter
84            implements ActionBar.TabListener, ViewPager.OnPageChangeListener {
85        private final Context mContext;
86        private final ActionBar mActionBar;
87        private final ViewPager mViewPager;
88        private final ArrayList<TabInfo> mTabs = new ArrayList<TabInfo>();
89
90        static final class TabInfo {
91            private final Class<?> clss;
92            private final Bundle args;
93
94            TabInfo(Class<?> _class, Bundle _args) {
95                clss = _class;
96                args = _args;
97            }
98        }
99
100        public TabsAdapter(Activity activity, ViewPager pager) {
101            super(activity.getFragmentManager());
102            mContext = activity;
103            mActionBar = activity.getActionBar();
104            mViewPager = pager;
105            mViewPager.setAdapter(this);
106            mViewPager.addOnPageChangeListener(this);
107        }
108
109        public void addTab(ActionBar.Tab tab, Class<?> clss, Bundle args) {
110            TabInfo info = new TabInfo(clss, args);
111            tab.setTag(info);
112            tab.setTabListener(this);
113            mTabs.add(info);
114            mActionBar.addTab(tab);
115            notifyDataSetChanged();
116        }
117
118        @Override
119        public int getCount() {
120            return mTabs.size();
121        }
122
123        @Override
124        public Fragment getItem(int position) {
125            TabInfo info = mTabs.get(position);
126            return Fragment.instantiate(mContext, info.clss.getName(), info.args);
127        }
128
129        @Override
130        public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
131        }
132
133        @Override
134        public void onPageSelected(int position) {
135            mActionBar.setSelectedNavigationItem(position);
136        }
137
138        @Override
139        public void onPageScrollStateChanged(int state) {
140        }
141
142        @Override
143        public void onTabSelected(Tab tab, FragmentTransaction ft) {
144            Object tag = tab.getTag();
145            for (int i=0; i<mTabs.size(); i++) {
146                if (mTabs.get(i) == tag) {
147                    mViewPager.setCurrentItem(i);
148                }
149            }
150        }
151
152        @Override
153        public void onTabUnselected(Tab tab, FragmentTransaction ft) {
154        }
155
156        @Override
157        public void onTabReselected(Tab tab, FragmentTransaction ft) {
158        }
159    }
160}
161//END_INCLUDE(complete)
162