se.chalmers.watchme.activity.TabsAdapter.java Source code

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Here is the source code for se.chalmers.watchme.activity.TabsAdapter.java

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/*
 * Copyright (C) 2012 The Android Open Source Project
 *
 * 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 se.chalmers.watchme.activity;

import java.util.ArrayList;

import android.app.ActionBar;
import android.app.ActionBar.Tab;
import android.content.Context;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentActivity;
import android.support.v4.app.FragmentPagerAdapter;
import android.support.v4.view.ViewPager;

/**
 * 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.
 * 
 * Class is available as example at
 * http://developer.android.com/reference/android/support/v4/view/ViewPager.html
 */
public class TabsAdapter extends FragmentPagerAdapter
        implements ActionBar.TabListener, ViewPager.OnPageChangeListener {

    private final Context context;
    private final ActionBar actionBar;
    private final ViewPager viewPager;
    private final ArrayList<TabInfo> tabs = new ArrayList<TabInfo>();

    static final class TabInfo {
        private final Class<?> clss;
        private final Bundle args;

        TabInfo(Class<?> clss, Bundle args) {
            this.clss = clss;
            this.args = args;
        }
    }

    public TabsAdapter(FragmentActivity activity, ViewPager pager) {
        super(activity.getSupportFragmentManager());
        this.context = activity;
        this.actionBar = activity.getActionBar();
        this.viewPager = pager;
        this.viewPager.setAdapter(this);
        this.viewPager.setOnPageChangeListener(this);
    }

    public void addTab(ActionBar.Tab tab, Class<?> clss, Bundle args) {
        TabInfo info = new TabInfo(clss, args);
        tab.setTag(info);
        tab.setTabListener(this);
        this.tabs.add(info);
        this.actionBar.addTab(tab);
        notifyDataSetChanged();
    }

    public void onPageScrollStateChanged(int state) {
    }

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

    public void onPageSelected(int position) {
        this.actionBar.setSelectedNavigationItem(position);
    }

    public void onTabReselected(Tab tab, android.app.FragmentTransaction ft) {
    }

    public void onTabSelected(Tab tab, android.app.FragmentTransaction ft) {
        Object tag = tab.getTag();
        for (int i = 0; i < this.tabs.size(); i++) {
            if (this.tabs.get(i) == tag) {
                this.viewPager.setCurrentItem(i);
            }
        }
    }

    public void onTabUnselected(Tab tab, android.app.FragmentTransaction ft) {
    }

    @Override
    public Fragment getItem(int position) {
        TabInfo info = this.tabs.get(position);
        return Fragment.instantiate(this.context, info.clss.getName(), info.args);
    }

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

}