2 * Copyright (C) 2009 The Android Open Source Project
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
8 * http://www.apache.org/licenses/LICENSE-2.0
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.
17 package org.altusmetrum.AltosDroid;
19 import java.util.ArrayList;
21 import android.content.Context;
22 import android.os.Bundle;
23 import android.support.v4.app.Fragment;
24 import android.support.v4.app.FragmentTransaction;
25 import android.support.v4.app.FragmentActivity;
26 import android.support.v4.app.FragmentPagerAdapter;
27 import android.support.v4.view.ViewPager;
28 import android.view.View;
29 import android.view.ViewGroup;
30 import android.widget.TabHost;
31 import android.widget.TabWidget;
32 import android.util.Log;
35 * This is a helper class that implements the management of tabs and all
36 * details of connecting a ViewPager with associated TabHost. It relies on a
37 * trick. Normally a tab host has a simple API for supplying a View or
38 * Intent that each tab will show. This is not sufficient for switching
39 * between pages. So instead we make the content part of the tab host
40 * 0dp high (it is not shown) and the TabsAdapter supplies its own dummy
41 * view to show as the tab content. It listens to changes in tabs, and takes
42 * care of switch to the correct paged in the ViewPager whenever the selected
45 public class TabsAdapter extends FragmentPagerAdapter
46 implements TabHost.OnTabChangeListener, ViewPager.OnPageChangeListener {
47 private final Context mContext;
48 private final TabHost mTabHost;
49 private final ViewPager mViewPager;
50 private final ArrayList<TabInfo> mTabs = new ArrayList<TabInfo>();
53 static class TabInfo {
54 private final String tag;
55 private final Class<?> clss;
56 private final Bundle args;
57 private Fragment fragment;
59 TabInfo(String _tag, Class<?> _class, Bundle _args) {
66 static class DummyTabFactory implements TabHost.TabContentFactory {
67 private final Context mContext;
69 public DummyTabFactory(Context context) {
73 public View createTabContent(String tag) {
74 View v = new View(mContext);
76 v.setMinimumHeight(0);
81 public TabsAdapter(FragmentActivity activity, TabHost tabHost, ViewPager pager) {
82 super(activity.getSupportFragmentManager());
86 mTabHost.setOnTabChangedListener(this);
87 mViewPager.setAdapter(this);
88 mViewPager.setOnPageChangeListener(this);
91 public void addTab(TabHost.TabSpec tabSpec, Class<?> clss, Bundle args) {
92 tabSpec.setContent(new DummyTabFactory(mContext));
93 String tag = tabSpec.getTag();
95 TabInfo info = new TabInfo(tag, clss, args);
97 mTabHost.addTab(tabSpec);
98 notifyDataSetChanged();
102 public int getCount() {
107 public Fragment getItem(int position) {
108 TabInfo info = mTabs.get(position);
109 Log.d(AltosDroid.TAG, String.format("TabsAdapter.getItem(%d)", position));
110 info.fragment = Fragment.instantiate(mContext, info.clss.getName(), info.args);
111 return info.fragment;
114 public Fragment currentItem() {
115 TabInfo info = mTabs.get(position);
116 return info.fragment;
119 public void onTabChanged(String tabId) {
120 AltosDroidTab prev_frag = (AltosDroidTab) mTabs.get(position).fragment;
122 position = mTabHost.getCurrentTab();
124 AltosDroidTab cur_frag = (AltosDroidTab) mTabs.get(position).fragment;
126 if (prev_frag != cur_frag) {
127 if (prev_frag != null) {
128 prev_frag.set_visible(false);
131 if (cur_frag != null) {
132 cur_frag.set_visible(true);
134 Log.d(AltosDroid.TAG, String.format("TabsAdapter.onTabChanged(%s) = %d", tabId, position));
135 mViewPager.setCurrentItem(position);
138 public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
141 public void onPageSelected(int position) {
142 // Unfortunately when TabHost changes the current tab, it kindly
143 // also takes care of putting focus on it when not in touch mode.
145 // This hack tries to prevent this from pulling focus out of our
147 TabWidget widget = mTabHost.getTabWidget();
148 int oldFocusability = widget.getDescendantFocusability();
149 widget.setDescendantFocusability(ViewGroup.FOCUS_BLOCK_DESCENDANTS);
150 mTabHost.setCurrentTab(position);
151 widget.setDescendantFocusability(oldFocusability);
154 public void onPageScrollStateChanged(int state) {