CODEWITHSUNDEEP
androidandroid-layoutandroid-recyclerview
user4165123
user4165123

Reputation: 183

getLayoutManager() returning null in RecyclerView adapter

I have a method in my fragment that looks like this:

    private void getFirstVisibleMediaRecyclerView() {
        int findFirstVisibleItemPosition = layoutManager.findFirstVisibleItemPosition();
        int findLastVisibleItemPosition = layoutManager.findLastVisibleItemPosition();

        int [] positions = { findFirstVisibleItemPosition, findLastVisibleItemPosition };

        Rect scrollBounds = new Rect();
        recyclerView.getDrawingRect(scrollBounds);

        int[] location = new int[2];
        for (int position : positions) {
            RecyclerView.ViewHolder item = recyclerView.findViewHolderForAdapterPosition(0);
            PostAdapter.PostViewHolder viewHolder = (PostAdapter.PostViewHolder) item;

            viewHolder.mediaRecyclerView.getLocationInWindow(location);

            if (location[1] < 0 || location[1] > scrollBounds.bottom) {
                //
            } else {
                viewHolder.doSomething();
            }
        }
    }

And my adapter class looks like this (I've removed parts that aren't important for this question):

public class PostAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> {

    public class PostViewHolder extends RecyclerView.ViewHolder {
        public RecyclerView mediaRecyclerView;

        public PostViewHolder(View v) {
            super(v);

            mediaRecyclerView = v.findViewById(R.id.media_recycler_view);
        }

        public void doSomething() {
            LinearLayoutManager layoutManager = (LinearLayoutManager) mediaRecyclerView.getLayoutManager();

            // !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
            // LAYOUT MANAGER IS NULL HERE AND I DON'T KNOW WHY
            // !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
            if (layoutManager == null) {
                return;
            }

            //
        }
    }

    @Override
    public void onBindViewHolder(@NonNull RecyclerView.ViewHolder holder, int position) {
            LinearLayoutManager layoutManager = new LinearLayoutManager(context, LinearLayoutManager.HORIZONTAL, false);
            holder.mediaRecyclerView.setLayoutManager(layoutManager);

            PostMediaAdapter mAdapter = new PostMediaAdapter(context, getData());

            holder.mediaRecyclerView.setAdapter(mAdapter);
    }
}

However, the layoutManager in the doSomething() method of the view holder is returning null, and I have no idea why.

Please help!

Upvotes: 0

Views: 531

Answers (1)

Abdul Rahman Majeed
Abdul Rahman Majeed

Reputation: 1135

First of all don't add layoutManager into onBindViewHolder you should add once your activity/fragment created.

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.id);

    binding.rvList.setLayoutManager(new LinearLayoutManager(context, LinearLayoutManager.HORIZONTAL, false))
}

because it effect performance of your application. try this remove form onBindViewHolder, what you want in doSomething() so I can suggest you need layoutManager object in adapter or its garbage.

Upvotes: 1

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