title: Adding Fragments to a LinearLayout programmatically
body: <p>I am trying to add nested child Fragments into a parent Fragment.</p>
  
  <p>All works fine but....</p>
  
  <p>At first my code:</p>
  
  <pre><code>public class FragmentDatasheetWithHeader extends Fragment {
     private long   mRowId;
     private String mSid;
  
     @Override
     public View onCreateView(final LayoutInflater inflater, final ViewGroup container, final Bundle savedInstanceState) {
  
        final ScrollView scrollView = new ScrollView(getActivity());
        final LinearLayout linearLayout = new LinearLayout(getActivity());
        linearLayout.setId(4711);
        linearLayout.setOrientation(LinearLayout.VERTICAL);
  
        scrollView.addView(linearLayout);
  
        createUI();
  
        return scrollView;
     }
  
     private void createUI() {
  
        final FragmentProductDetailHeader fragmentHeader = FragmentProductDetailHeader.newInstance(this.mRowId, FragmentProductDetailHeader.HEADERTYPE_SMALL);
        final FragmentDatasheet fragmentDatasheet = FragmentDatasheet.newInstance(this.mRowId, this.mSid);
  
        final FragmentManager fragmentManager = getChildFragmentManager();
        fragmentManager.beginTransaction().add(4711, fragmentHeader, "fragmentHeader").commit();
        fragmentManager.beginTransaction().add(4711, fragmentDatasheet, "fragmentDatasheet").commit();
     }
  }
  </code></pre>
  
  <p>Now my problem:</p>
  
  <p>In the Developer options I activated "Don't keep activities (Destroy every activity as soon the user leaves it)"</p>
  
  <p>When the activity with the FragmentDatasheetWithHeader is open and the app goes into background and comes back to foreground the nested Fragments are doubled. But it only appears if the container for the nested Fragments is a LinearLayout. If the container is a FrameLayout the nested Fragments are not doubled.</p>
  
  <p>What's going wrong?</p>