Don't reload Fragment's Data after backstack

Question

I have a fragment (MyListFragment) which is a Fragment, i have a list there called myList

this list gets filled with json data onCreateView().

myList -> onItemClick -> open details fragment

after i press the back button the myList list gets reloaded again, i don't want that to happen, instead i want the first fragment to retain the initial state with the loaded data, i used the SlidingPaneLayout for both List/Details fragments, but now i want to use the fragmenttransaction instead cuz i need the SlidingPaneLayout for the menu usage, instead of the list|details slide.

here's a bit of my script

public class MyListFragment extends Fragment {

private AsyncCallBack           callback;

public static RelativeLayout    loadingListLayout;
public static RelativeLayout    listCarsLayout;

public DetailsFragment          detailsFragment;

public ArrayList<String>        loadedCars              = new ArrayList<String>();

public static String            loadedCarsString        = "";
public static Boolean           jsonCarsLoading         = false;
public String                   latestDate;

public static long              selectedItem            = -1;

public static Boolean           isRefreshing            = false;

public PullToRefreshListView    myList;
public CarsAdapter              carsAdapter;
public ArrayList<CarsItems>     carsItems;
public ArrayList<CarsItems>     results                 = new ArrayList<CarsItems>();

public static int               ON_LOAD_ITEM_COUNT      = 20;
public static int               ON_REFRESH_ITEM_COUNT   = 10;
public static int               ON_LOADMORE_ITEM_COUNT  = 3;

int                             currentFirstVisibleItem, currentVisibleItemCount, currentTotalItemCount, currentScrollState;

private View                    view;

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

    super.onCreateView(inflater, container, savedInstanceState);

    view = inflater.inflate(R.layout.list_fragment, container, false);

    loadingListLayout = (RelativeLayout) view.findViewById(R.id.LoadingListLayout);
    listCarsLayout = (RelativeLayout) view.findViewById(R.id.ListLayout);

    myList = (PullToRefreshListView) view.findViewById(R.id.CarsList);
    detailsFragment = new DetailsFragment();

    carsAdapter = new CarsAdapter(getActivity(), results);
    myList.setAdapter(carsAdapter);

     ...

    // Get Cars List if online
    if (isOnline()) {
        Api jsonCars = new Api();
        jsonCars.setLimit(ON_LOAD_ITEM_COUNT);
        jsonCars.setCallBack(callback);
        jsonCars.getLatestItemDate = true;
        jsonCars.setExcludeCars(loadedCarsString);
        jsonCars.execute("latestCars");
    }

i tried to implement the code inside the onAttach(), but whatever i type in there i guet onLaunchActivity error.....

Answer 1

I solved this issue with the help of savedInstanceState()

    private Calendar startTime = Calendar.getInstance();


    @Override
    public void onSaveInstanceState(Bundle outState) {
        super.onSaveInstanceState(outState);
        outState.putSerializable("starttime", startTime);
    }

i used to load the dataList inside onCreateView, without any condition, so anyway, when i put this code, and checked back the fragment after pressing the Back button, it seemed that the fragment saved it's instance state, like the position and data, but it kept loading the data (Running the AsyncTask again and again);

so i had to put some conditions:

• First

  i added this line at the top of my fragment class

  public Boolean initialized = false;
  

  to be updated later after first run with 'true';

• Second

  then added those to the onCreateView() before loading the data

  if (initialized == false) {
      loadList();
  } else {
      loadingListLayout.setVisibility(View.GONE);
      listLayout.setVisibility(1);
  }
  

  the loadingListLayout is just an overlay with a progress bar whilst the data is being loaded

• Third

  and then inside the loadlist() i added :

  public void loadList() {
      initialized = true;
          ...
            ran the AsyncTask ...
  

this way i ensured that the data AsyncTask doesn't get executed everytime i press the backbutton, this way i managed to keep using the the addToBackStack for my fragmentTransaction thing.

Answer 2

i solved it this way, adding those methods to my fragment

public int dismiss() {
    try {
        if (mBackStackId != -1) {
            FragmentManager fm = getFragmentManager();
            fm.popBackStack(mBackStackId, FragmentManager.POP_BACK_STACK_INCLUSIVE);
            mBackStackId = -1;
            FragmentTransaction ft = fm.beginTransaction();
            ft.remove(this);
            ft.commit();
        }
    } catch (IllegalArgumentException e) {
        return mBackStackId;
    }
    return mBackStackId;
}

public int show(FragmentManager fm) {
    FragmentTransaction ft = fm.beginTransaction();
    ft.add(android.R.id.content, this, TAG);
    ft.addToBackStack(null);
    mBackStackId = ft.commit();
    return mBackStackId;
}