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 androidx.fragment.app.Fragment;
24 import androidx.fragment.app.FragmentActivity;
25 import androidx.fragment.app.FragmentPagerAdapter;
26 import androidx.viewpager.widget.ViewPager;
27 import android.view.View;
28 import android.view.ViewGroup;
29 import android.widget.TabHost;
30 import android.widget.TabWidget;
33 * This is a helper class that implements the management of tabs and all
34 * details of connecting a ViewPager with associated TabHost. It relies on a
35 * trick. Normally a tab host has a simple API for supplying a View or
36 * Intent that each tab will show. This is not sufficient for switching
37 * between pages. So instead we make the content part of the tab host
38 * 0dp high (it is not shown) and the TabsAdapter supplies its own dummy
39 * view to show as the tab content. It listens to changes in tabs, and takes
40 * care of switch to the correct paged in the ViewPager whenever the selected
43 public class TabsAdapter extends FragmentPagerAdapter
44 implements TabHost.OnTabChangeListener, ViewPager.OnPageChangeListener {
45 private final Context mContext;
46 private final TabHost mTabHost;
47 private final ViewPager mViewPager;
48 private final ArrayList<TabInfo> mTabs = new ArrayList<TabInfo>();
51 static class TabInfo {
52 private final String tag;
53 private final Class<?> clss;
54 private final Bundle args;
55 private Fragment fragment;
57 TabInfo(String _tag, Class<?> _class, Bundle _args) {
64 static class DummyTabFactory implements TabHost.TabContentFactory {
65 private final Context mContext;
67 public DummyTabFactory(Context context) {
71 public View createTabContent(String tag) {
72 View v = new View(mContext);
74 v.setMinimumHeight(0);
79 public TabsAdapter(FragmentActivity activity, TabHost tabHost, ViewPager pager) {
80 super(activity.getSupportFragmentManager());
84 mTabHost.setOnTabChangedListener(this);
85 mViewPager.setAdapter(this);
86 mViewPager.addOnPageChangeListener(this);
89 public void addTab(TabHost.TabSpec tabSpec, Class<?> clss, Bundle args) {
90 tabSpec.setContent(new DummyTabFactory(mContext));
91 String tag = tabSpec.getTag();
93 TabInfo info = new TabInfo(tag, clss, args);
95 mTabHost.addTab(tabSpec);
96 notifyDataSetChanged();
100 public int getCount() {
105 public Fragment getItem(int position) {
106 TabInfo info = mTabs.get(position);
107 AltosDebug.debug("TabsAdapter.getItem(%d)", position);
108 info.fragment = Fragment.instantiate(mContext, info.clss.getName(), info.args);
109 return info.fragment;
112 public Fragment currentItem() {
113 TabInfo info = mTabs.get(position);
114 return info.fragment;
117 public void onTabChanged(String tabId) {
118 AltosDroidTab prev_frag = (AltosDroidTab) mTabs.get(position).fragment;
120 position = mTabHost.getCurrentTab();
122 AltosDroidTab cur_frag = (AltosDroidTab) mTabs.get(position).fragment;
124 if (prev_frag != cur_frag) {
125 if (prev_frag != null) {
126 prev_frag.set_visible(false);
129 if (cur_frag != null) {
130 cur_frag.set_visible(true);
132 AltosDebug.debug("TabsAdapter.onTabChanged(%s) = %d", tabId, position);
133 mViewPager.setCurrentItem(position);
136 public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
139 public void onPageSelected(int position) {
140 // Unfortunately when TabHost changes the current tab, it kindly
141 // also takes care of putting focus on it when not in touch mode.
143 // This hack tries to prevent this from pulling focus out of our
145 TabWidget widget = mTabHost.getTabWidget();
146 int oldFocusability = widget.getDescendantFocusability();
147 widget.setDescendantFocusability(ViewGroup.FOCUS_BLOCK_DESCENDANTS);
148 mTabHost.setCurrentTab(position);
149 widget.setDescendantFocusability(oldFocusability);
152 public void onPageScrollStateChanged(int state) {