"LayoutManager is already attached to a RecyclerView" error

Just need to create a new instance:

RecyclerView recyclerView = new RecyclerView(getContext());
recyclerView.setLayoutManager(new LinearLayoutManager(getContext()))

I had this problem too. My Activity uses Tabs, with three fragments, when I go to third tab, and back to first (or second), this error is thrown.

After searching a lot, I found out that may be the garbage collector, because I was using a strong reference.

Since the constructor LinearLayoutManager uses the activity as the parameter (not the fragment), a Tabs Activity stays active during tabs changes.

Removing the local field in mLinearLayoutManager from the class, and using a weak reference, I could get rid of this problem:

before:

public class MyFragment1 extends Fragment
    private LinearLayoutManager linearLayoutManager;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        linearLayoutManager = new LinearLayoutManager(getActivity());
        (...)
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {
        (...)
        mRecyclerView.setLayoutManager(linearLayoutManager);
    }
}

I changed to:

public class MyFragment1 extends Fragment {
    // private LinearLayoutManager linearLayoutManager;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        // linearLayoutManager = new LinearLayoutManager(getActivity());
        (...)
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        (...)
        mRecyclerView.setLayoutManager(
           new LinearLayoutManager(getActivity()));
    }
}

I faced this error when providing LayoutManager via Dagger.
The solution is to replace layout manager injection with layout manager javax.inject.Provider injection.

@Inject
lateinit var layoutManager: Provider<RecyclerView.LayoutManager>

...

recyclerView.setLayoutManager(layoutManager.get())