Using findFragmentById with ViewPager

My app has a list and detail view where I allow the user to scroll between different points of view using ViewPager

in portrait. In landscape, I show both fragments on the screen.

I have a problem where when the device is rotated the icons duplicate themselves over and over in Actionbar

. I found out that I probably create new fragments whenever the device is rotated, and I have to check if the fragment is in FragmentManager

and then instantiate a new one if it is not.

I can do this easily using landscape layout, however I am not sure how to check if a fragment exists in portrait mode using ViewPager

. Am I doing this at getItem()

FragmentStatePagerAdapter

?

This is the code I'm using:

public class Main extends SherlockFragmentActivity
{
    private static List<Integer> mIds;

    @Override
    public void onCreate(final Bundle icicle)
    {    
        super.onCreate(icicle);

        setContentView(R.layout.main);

        mViewPager = (ViewPager)findViewById(R.id.viewpager); //view pager exists, so we are using the portait layout

        if (mViewPager != null)
        {
            mIds = new ArrayList<Integer>();

            mIds.add(0);
            mIds.add(1);
            mIds.add(2);
        }
        else //in landscape
        {           
            ListFragment lf = (ListFragment)getSupportFragmentManager().findFragmentById(R.id.fragmentList);

            if (lf == null)
                lf = new ListFragment();

            DetailFragment df = (DetailFragment)getSupportFragmentManager().findFragmentById(R.id.fragmentDetail);

            if (df == null)
            {
                df = new DetailFragment();
                df.setArguments(getIntent().getExtras());   
            }

            getSupportFragmentManager().beginTransaction().add(R.id.fragmentList, lf).commit();
            getSupportFragmentManager().beginTransaction().add(R.id.fragmentDetail, df).commit();
        }
    }       

    private static class MyFragmentPagerAdapter extends FragmentStatePagerAdapter  {  

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

        @Override  
        public Fragment getItem(int index) {        
            //can't use getSupportFragmentManager().findFragmentById() here because I get a "Cannot make a static reference to the non-static method" error
            if (index == 0)
                return ListFragment.newInstance();
            else            
                return DetailFragment.newInstance(mIds.get(index-1));
        }  

        @Override
        public int getCount() {  
             return 4;
        }
   }  
}

      

        
        
        
      

    

Main layout (portrait)

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_height="fill_parent"
    android:layout_width="fill_parent">

    <android.support.v4.view.ViewPager
        android:id="@+id/viewpager"
        android:layout_height="match_parent"
        android:layout_width="match_parent"
     />
 </RelativeLayout>

      

        
        
        
      

    

Main layout (landscape)

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="horizontal"
    android:layout_height="fill_parent"
    android:layout_width="fill_parent"
    android:weightSum="3"
>
    <FrameLayout 
        android:id="@+id/fragmentList"
        android:layout_weight="1"
        android:layout_width="0dp"
        android:layout_height="fill_parent"
     />

    <FrameLayout 
        android:id="@+id/fragmentDetail"
        android:layout_width="0dp"
        android:layout_weight="2"
        android:layout_height="fill_parent"
     />

</LinearLayout>

      

        
        
        
      

    

Fragment of the list

public class ListFragment extends SherlockListFragment implements DialogKeywordAddListener
{
    @Override
    public void onCreate(Bundle savedInstanceState){
        super.onCreate(savedInstanceState);

        setHasOptionsMenu(true);
    }

    public static ListFragment newInstance() {

        return new ListFragment();
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        super.onCreateView(inflater, container, savedInstanceState);

        return inflater.inflate(R.layout.listing, container, false);
    }
}

      

        
        
        
      

    

Detail fragment

public class DetailFragment extends SherlockListFragment
{
    private int mId;

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

        setHasOptionsMenu(true);
    }

    public static DetailFragment newInstance() {

        DetailFragment df = new DetailFragment();
        Bundle bundle = new Bundle();
        bundle.putInt("id", id);
        df.setArguments(bundle);

        return df;
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        super.onCreateView(inflater, container, savedInstanceState);

        if (getArguments() != null)
            mId = getArguments().getInt("id");

        return inflater.inflate(R.layout.detail, container, false);
    }
}