at.the.gogo.parkoid.fragments.FragmentTabsPager.java Source code

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Here is the source code for at.the.gogo.parkoid.fragments.FragmentTabsPager.java

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package at.the.gogo.parkoid.fragments;

/*
 * Copyright (C) 2011 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.
 */

import java.util.ArrayList;

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;
import android.view.View;
import android.widget.TabHost;
import at.the.gogo.parkoid.R;

/**
 * Demonstrates combining a TabHost with a ViewPager to implement a tab UI that
 * switches between tabs and also allows the user to perform horizontal flicks
 * to move between the tabs.
 */
public class FragmentTabsPager extends FragmentActivity {
    TabHost mTabHost;
    ViewPager mViewPager;
    TabsAdapter mTabsAdapter;

    @Override
    protected void onCreate(final Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        setContentView(R.layout.fragment_tabs_pager);
        mTabHost = (TabHost) findViewById(android.R.id.tabhost);
        mTabHost.setup();

        mViewPager = (ViewPager) findViewById(R.id.pager);

        mTabsAdapter = new TabsAdapter(this, mTabHost, mViewPager);

        mTabsAdapter.addTab(mTabHost.newTabSpec("overview").setIndicator("Overview"), OverviewFragment.class, null);

        mTabsAdapter.addTab(mTabHost.newTabSpec("map").setIndicator("Map"), MapFragment.class, null);

        mTabsAdapter.addTab(mTabHost.newTabSpec("address").setIndicator("Address"), AddressListFragment.class,
                null);

        mTabsAdapter.addTab(mTabHost.newTabSpec("car").setIndicator("Cars"), CarListFragment.class, null);

        if (savedInstanceState != null) {
            mTabHost.setCurrentTabByTag(savedInstanceState.getString("tab"));
        }
    }

    @Override
    protected void onSaveInstanceState(final Bundle outState) {
        super.onSaveInstanceState(outState);
        outState.putString("tab", mTabHost.getCurrentTabTag());
    }

    /**
     * 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 static class TabsAdapter extends FragmentPagerAdapter
            implements TabHost.OnTabChangeListener, ViewPager.OnPageChangeListener {
        private final Context mContext;
        private final TabHost mTabHost;
        private final ViewPager mViewPager;
        private final ArrayList<TabInfo> mTabs = new ArrayList<TabInfo>();

        static final class TabInfo {
            @SuppressWarnings("unused")
            private final String tag;
            private final Class<?> clss;
            private final Bundle args;

            TabInfo(final String _tag, final Class<?> _class, final Bundle _args) {
                tag = _tag;
                clss = _class;
                args = _args;
            }
        }

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

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

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

        public TabsAdapter(final FragmentActivity activity, final TabHost tabHost, final ViewPager pager) {
            super(activity.getSupportFragmentManager());
            mContext = activity;
            mTabHost = tabHost;
            mViewPager = pager;
            mTabHost.setOnTabChangedListener(this);
            mViewPager.setAdapter(this);
            mViewPager.setOnPageChangeListener(this);
        }

        public void addTab(final TabHost.TabSpec tabSpec, final Class<?> clss, final Bundle args) {
            tabSpec.setContent(new DummyTabFactory(mContext));
            final String tag = tabSpec.getTag();

            final TabInfo info = new TabInfo(tag, clss, args);
            mTabs.add(info);
            mTabHost.addTab(tabSpec);
            notifyDataSetChanged();
        }

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

        @Override
        public Fragment getItem(final int position) {
            final TabInfo info = mTabs.get(position);
            return Fragment.instantiate(mContext, info.clss.getName(), info.args);
        }

        @Override
        public void onTabChanged(final String tabId) {
            final int position = mTabHost.getCurrentTab();
            mViewPager.setCurrentItem(position);
        }

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

        @Override
        public void onPageSelected(final int position) {
            mTabHost.setCurrentTab(position);
        }

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