单击选项卡时如何更新片段

Question

每次单击其选项卡时，我都想创建一个新片段。 我试图获取选项卡并创建一个片段。但它似乎没有用。

这是我的代码。

主要活动

public class MainActivity extends FragmentActivity {

    private static ViewPager viewPager;
    private static TabsPagerAdapter mAdapter;
    private static ActionBar actionBar;

    // Tab titles
    private String[] tabs = { "TopRated", "Hots", "NEW"};

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        // Initialization
        viewPager = (ViewPager) findViewById(R.id.pager);
        actionBar = getActionBar();
        mAdapter = new TabsPagerAdapter(getSupportFragmentManager());

        viewPager.setAdapter(mAdapter);
        //actionBar.setHomeButtonEnabled(false);
        actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);        

        // Adding Tabs
        for (String tab_name : tabs) {
            actionBar.addTab(actionBar.newTab().setText(tab_name).setTabListener(tabListener));
        }

        /**
         * on swiping the viewpager make respective tab selected
         * */
        viewPager.setOnPageChangeListener(new ViewPager.OnPageChangeListener() {

            @Override
            public void onPageSelected(int position) {
                // on changing the page
                // make respected tab selected
                actionBar.setSelectedNavigationItem(position);
            }

            @Override
            public void onPageScrolled(int arg0, float arg1, int arg2) {
            }

            @Override
            public void onPageScrollStateChanged(int arg0) {
            }
        });
    }

    static ActionBar.TabListener tabListener = new ActionBar.TabListener() {
        @Override
        public void onTabReselected(Tab tab, FragmentTransaction ft) {
        }
        @Override
        public void onTabSelected(Tab tab, FragmentTransaction ft) {
            viewPager.setCurrentItem(tab.getPosition());
        }
        @Override
        public void onTabUnselected(Tab tab, FragmentTransaction ft) {
        }
    };

TabsPagerAdapter

public class TabsPagerAdapter extends FragmentPagerAdapter {

    public TabsPagerAdapter(FragmentManager fm) {
        super(fm);
    }

    @Override
    public int getItemPosition(Object object) {
        return POSITION_NONE;
    }

    @Override
    public Fragment getItem(int index) {
        switch (index) {
            case 0:
                return new TopRatedFragment();
            case 1:
                return new HotStoryFragment();
            case 2:
                return new AllClassFragment();
        }

        return null;                                           
    }

    @Override
    public int getCount() {
        // get item count - equal to number of tabs
        return 3;
    }

其中一个片段

public class HotStoryFragment extends Fragment {

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                Bundle savedInstanceState) {
        Log.d("Refresh_F","(2) HotStory");

        View rootView = inflater.inflate(R.layout.fragment_hotstory, container, false);

        TextView tvStudy = (TextView)rootView.findViewById(R.id.text);

        return rootView;
    }