从mainactivity更新片段

Question

我正在使用带有SectionsPagerAdapter和PlaceholderFragment的ActionBar编写程序。我在MainActivity中通过BroadcastReceiver接收数据，我想知道当我在BroadcastReceiver中收到某些数据时如何更新当前片段。我是一个初学者，我找到了许多替代品，但没有使用占位符（像我的），这种方法（占位符）是我发现很好解释和开发的唯一例子。提前致谢

public class MainActivity extends Activity implements ActionBar.TabListener
{
SectionsPagerAdapter mSectionsPagerAdapter;

ViewPager mViewPager;

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

    final ActionBar actionBar = getActionBar();
    actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);

    mSectionsPagerAdapter = new SectionsPagerAdapter(getFragmentManager());

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

    mViewPager.setOnPageChangeListener(new ViewPager.SimpleOnPageChangeListener()
        {
        @Override
        public void onPageSelected(int position)
            {
            actionBar.setSelectedNavigationItem(position);
            }
        });

    for (int i = 0; i < mSectionsPagerAdapter.getCount(); i++)
        {
        actionBar.addTab(actionBar.newTab()
                .setText(mSectionsPagerAdapter.getPageTitle(i))
                .setTabListener(this));
        }

    }

@Override
public boolean onCreateOptionsMenu(Menu menu)
    {
    getMenuInflater().inflate(R.menu.main, menu);
    return true;
    }

@Override
public boolean onOptionsItemSelected(MenuItem item)
    {
    int id = item.getItemId();
    if (id == R.id.action_settings)
        {
        return true;
        }
    return super.onOptionsItemSelected(item);
    }

@Override
public void onTabSelected(ActionBar.Tab tab, FragmentTransaction fragmentTransaction)
    {
    mViewPager.setCurrentItem(tab.getPosition());
    }

@Override
public void onTabUnselected(ActionBar.Tab tab, FragmentTransaction fragmentTransaction)
    {
    }

@Override
public void onTabReselected(ActionBar.Tab tab, FragmentTransaction fragmentTransaction)
    {
    }

public class SectionsPagerAdapter extends FragmentPagerAdapter
    {
    public SectionsPagerAdapter(FragmentManager fm)
        {
        super(fm);
        }

    @Override
    public Fragment getItem(int position)
        {
        return PlaceholderFragment.newInstance(position);
        }

    @Override
    public int getCount()
        {
        return 3;
        }

    @Override
    public CharSequence getPageTitle(int position)
        {
        Locale l = Locale.getDefault();
        switch (position)
            {
            case 0:
                return getString(R.string.title_section1).toUpperCase(l);
            case 1:
                return getString(R.string.title_section2).toUpperCase(l);
            case 2:
                return getString(R.string.title_section3).toUpperCase(l);
            }
        return null;
        }
    }

public static class PlaceholderFragment extends Fragment
    {
    private static final String ARG_SECTION_NUMBER = "section_number";
    public View rootView;
    private ToggleButton togg_Connect;

    public static PlaceholderFragment newInstance(int sectionNumber)
        {
        PlaceholderFragment fragment = new PlaceholderFragment();
        Bundle args = new Bundle();
        args.putInt(ARG_SECTION_NUMBER, sectionNumber);
        fragment.setArguments(args);
        return fragment;
        }

    public PlaceholderFragment()
        {
        }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
        {
        switch (getArguments().getInt(ARG_SECTION_NUMBER))
            {
            case 2:
                rootView = inflater.inflate(R.layout.fragment_page3, container, false);
                break;
            case 1:
                rootView = inflater.inflate(R.layout.fragment_page2, container, false);


                break;
            default:
                rootView = inflater.inflate(R.layout.fragment_main, container, false);
                break;
            }
        return rootView;
        }

    @Override
    public void onDestroyView()
        {
        switch (getArguments().getInt(ARG_SECTION_NUMBER))
            {
            case 2:

                break;
            case 1:

                break;
            default:
                break;
            }
        super.onDestroyView();
        }

    @Override
    public void setUserVisibleHint(boolean isVisibleToUser)
        {
        super.setUserVisibleHint(isVisibleToUser);
        }

    }

private BroadcastReceiver ApplicationReceiver = new BroadcastReceiver()
    {
    @Override
    public void onReceive(Context context, Intent mIntent)
        {

                    **********************************************
                    **********************************************
                    **********************************************
                    NOW AT THIS POINT I WANT TO UPDATE THE CURRENT
                         FRAGMENT ACCORDING THE RECEIVED DATA
                    **********************************************
                    **********************************************
                    **********************************************

        return;
        }
    };
}