br.com.cybereagle.androidlibrary.ui.adapter.TabsAdapter.java Source code

Introduction

Here is the source code for br.com.cybereagle.androidlibrary.ui.adapter.TabsAdapter.java

Source

/*
 * Copyright 2013 Cyber Eagle
 *
 *    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 br.com.cybereagle.androidlibrary.ui.adapter;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import android.content.Context;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentActivity;
import android.support.v4.app.FragmentPagerAdapter;
import android.support.v4.view.ViewPager;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TabHost;
import android.widget.TabWidget;

/**
 * This is a helper class that implements the management of tabs and all
 * details of connecting a ViewPager with associated TabHost.  It relies on a
 * trick.  Normally a tab host has a simple API for supplying a View or
 * Intent that each tab will show.  This is not sufficient for switching
 * between pages.  So instead we make the content part of the tab host
 * 0dp high (it is not shown) and the TabsAdapter supplies its own dummy
 * view to show as the tab content.  It listens to changes in tabs, and takes
 * care of switch to the correct paged in the ViewPager whenever the selected
 * tab changes.
 */
public class TabsAdapter extends FragmentPagerAdapter
        implements TabHost.OnTabChangeListener, ViewPager.OnPageChangeListener {
    private final Context context;
    private final TabHost tabHost;
    private final ViewPager viewPager;
    private final List<String> tags = new ArrayList<String>();

    private final Map<String, Fragment> mapFragments = new HashMap<String, Fragment>();

    static class DummyTabFactory implements TabHost.TabContentFactory {
        private final Context mContext;

        public DummyTabFactory(Context context) {
            mContext = context;
        }

        @Override
        public View createTabContent(String tag) {
            View v = new View(mContext);
            v.setMinimumWidth(0);
            v.setMinimumHeight(0);
            return v;
        }
    }

    public TabsAdapter(FragmentActivity activity, TabHost tabHost, ViewPager pager) {
        super(activity.getSupportFragmentManager());
        this.context = activity;

        this.tabHost = tabHost;
        this.viewPager = pager;
        this.tabHost.setOnTabChangedListener(this);
        this.viewPager.setAdapter(this);
        this.viewPager.setOnPageChangeListener(this);
    }

    public void addTab(TabHost.TabSpec tabSpec, Fragment fragment) {
        tabSpec.setContent(new DummyTabFactory(context));
        String tag = tabSpec.getTag();

        mapFragments.put(tag, fragment);
        tags.add(tag);
        tabHost.addTab(tabSpec);
        notifyDataSetChanged();
    }

    @Override
    public int getCount() {
        return tags.size();
    }

    @Override
    public Fragment getItem(int position) {
        String tag = tags.get(position);
        return mapFragments.get(tag);
    }

    @Override
    public void onTabChanged(String tabId) {
        int position = tabHost.getCurrentTab();
        viewPager.setCurrentItem(position);
    }

    @Override
    public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
    }

    @Override
    public void onPageSelected(int position) {
        // Unfortunately when TabHost changes the current tab, it kindly
        // also takes care of putting focus on it when not in touch mode.
        // The jerk.
        // This hack tries to prevent this from pulling focus out of our
        // ViewPager.
        TabWidget widget = tabHost.getTabWidget();
        int oldFocusability = widget.getDescendantFocusability();
        widget.setDescendantFocusability(ViewGroup.FOCUS_BLOCK_DESCENDANTS);
        tabHost.setCurrentTab(position);
        widget.setDescendantFocusability(oldFocusability);
    }

    @Override
    public void onPageScrollStateChanged(int state) {
    }
}