org.pyload.android.client.components.FragmentTabsPager.java Source code

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Here is the source code for org.pyload.android.client.components.FragmentTabsPager.java

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/*
 * 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.
 */
package org.pyload.android.client.components;

import java.util.ArrayList;

import org.pyload.android.client.R;
import org.pyload.android.client.pyLoadApp;

import android.content.Context;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentActivity;
import android.support.v4.view.ViewPager;
import android.view.View;
import android.view.Window;
import android.widget.TabHost;

/**
 * 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 {
    protected TabHost mTabHost;
    protected ViewPager mViewPager;
    protected TabsAdapter mTabsAdapter;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        if (!pyLoadApp.isActionBarAvailable()) {
            requestWindowFeature(Window.FEATURE_INDETERMINATE_PROGRESS);
        }

        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);

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

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

    public int getCurrentTab() {
        return mTabHost.getCurrentTab();
    }

    public Fragment getCurrentFragment() {
        return mTabsAdapter.getFragment(getCurrentTab());
    }

    /**
     * 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>();
        private int selected = 0;

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

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

        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());
            mContext = activity;
            mTabHost = tabHost;
            mViewPager = pager;
            mTabHost.setOnTabChangedListener(this);
            mViewPager.setAdapter(this);
            mViewPager.setOnPageChangeListener(this);
        }

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

            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(int position) {
            TabInfo info = mTabs.get(position);

            Fragment frag = Fragment.instantiate(mContext, info.clss.getName(), info.args);

            ((TabHandler) frag).setPosition(position);

            return frag;
        }

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

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

        @Override
        public void onPageSelected(int position) {

            Fragment pos = getFragment(position);
            if (pos != null)
                ((TabHandler) pos).onSelected();

            Fragment old = getFragment(selected);
            if (old != null && selected != position)
                ((TabHandler) old).onDeselected();

            mTabHost.setCurrentTab(position);
            selected = position;
        }

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