how to add view to fragment in onCreate

Question

I'm using a ViewPager in my Activity which has multiple Fragments. in the onCreate method of my Activity, I want to add multiple views to one of those fragments so that they can be seen at start. the problem is that i can not find a way to access that fragment. how to do that? I have tried to access the RecyclerView of that fragment at this way:

public class CaafeFragment extends Fragment {

private RecyclerView recyclerView = null;

public CaafeFragment() {
    // Required empty public constructor
}


@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {
    // Inflate the layout for this fragment
    View view = inflater.inflate(R.layout.fragment_caafe, container, false);
    recyclerView = (RecyclerView) view.findViewById(R.id.caafeRecyclerView);
    return view;
}

public RecyclerView getRecyclerView() {
    return (RecyclerView) getView().findViewById(R.id.caafeRecyclerView);
}
}

but it returns null when i call getRecyclerView() from the onCreate() of my activity

// activity

public void onCreate()
{
 .
 .
 .
 CaafeFragment caafeFragment=new CaafeFragment();
 caafeRecyclerView = caafeFragment.getRecyclerView(); // here it returns null
}

Please post the code where u are trying to access the recyclerview from the activity — JpCrow, Feb 24 '16 at 01:06
sure it returns null, `onCreateView` in the fragment wasn't called. — Jörn Buitink, Feb 24 '16 at 08:42
@JörnBuitink, yes, u r correct, but what is the solution?!!! — Soheil, Feb 24 '16 at 08:48

score 1 · Answer 1 · edited May 23 '17 at 12:16

1

After the onCreate() is called (in the Fragment), the Fragment's onCreateView() is called due to this is throws error as you have declared recycleview in onCreate() method.

Check onCreate(), onCreateView() difference for more detail.

ex:

ExampleFragment fragment = (ExampleFragment) getFragmentManager().findFragmentById(R.id.example_fragment);
fragment.<specific_function_name>();

edited May 23 '17 at 12:16

Community

1
1

answered Feb 24 '16 at 08:45

Amit Vaghela

22,772
22
86
142

just as u said, it seems clear that `onCreateView()` is not called at that stage. how to solve it?! – Soheil Feb 24 '16 at 09:00
http://stackoverflow.com/questions/10903077/calling-a-fragment-method-from-a-parent-activity – Amit Vaghela Feb 24 '16 at 09:06

Talha · Answer 2 · 2016-02-24T16:51:39.627

CaafeFragment caafeFragment=new CaafeFragment();

caafeFragment points to nothing, it should refer a fragment, this line just creates fragment object. You are trying to get something that it does not contain. You should specify which fragment that object holds:

CaafeFragment caafeFragment=(CaafeFragment) getFragmentManager().findFragmentById(R.id.YOUR_FRAGMENT_ID);

caafeRecyclerView = caafeFragment.getRecyclerView();

Now the caafeFragment object contains something you can access from.

EDIT

You should return the private RecyclerView recyclerView object that you set via "view" in OnCreate(),

in getRecyclerView()

replace ~~return (RecyclerView) getView().findViewById(R.id.caafeRecyclerView);~~ by:

public RecyclerView getRecyclerView() {
    return recyclerView;
}

What is certain here is that recyclerView object holds view that is instantiated, and this line can be tracked to make sure that, in onCreate(),

 recyclerView = (RecyclerView) view.findViewById(R.id.caafeRecyclerView);

Has value or not.

Also have a look at this question http://stackoverflow.com/questions/8785221/retrieve-a-fragment-from-a-viewpager — Talha, Feb 24 '16 at 16:23
You can try this to get fragments: http://tamsler.blogspot.com/2011/11/android-viewpager-and-fragments-part-ii.html — Talha, Feb 24 '16 at 16:53

how to add view to fragment in onCreate

2 Answers2

ex: