CODEWITHSUNDEEP
androidandroid-recyclerview
Alex
Alex

Reputation: 61

RecyclerView doesn't get updated

The problem is that my RecyclerView doesn't get updated unless I set a new adapter. Here's the code: 

    TransferLab transferLab = TransferLab.get(getActivity());
    List<Transfer> transfers = transferLab.getTransfers();

    if (mAdapter == null) {
        mAdapter = new TransferAdapter(transfers);
        mTransferRecyclerView.setAdapter(new TransferAdapter(transfers));
    } else {
        mAdapter.setTransfers(transfers);
        mAdapter.notifyDataSetChanged();
    }

As you see I get a new list and pass it into the adapter. But the RecyclerView doesn't change until I restart the app or replace the IF-section with the code below:

        mAdapter = new TransferAdapter(transfers);
        mTransferRecyclerView.setAdapter(new TransferAdapter(transfers));

Inside the adapter:

    private class TransferAdapter extends RecyclerView.Adapter<TransferViewHolder> {

    private List<Transfer> mTransfers;


    public TransferAdapter(List<Transfer> transfers) {
        mTransfers = transferList;
    }

    public void setTransfers(List<Transfer> transfers) {
        mTransfers = transfers;
    }

    @NonNull
    @Override
    public TransferViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        LayoutInflater inflater = LayoutInflater.from(getActivity());
        return new TransferViewHolder(inflater, parent);
    }

    @Override
    public void onBindViewHolder(@NonNull TransferViewHolder holder, int position) {
        holder.bind(mTransfers.get(position));
    }

    @Override
    public int getItemCount() {
        return mTransfers.size();
    }

}

Upvotes: 1

Views: 39

Answers (2)

Marat
Marat

Reputation: 6703

You are not setting mAdapter to your mTransferRecyclerView but rather creating a new instance of TransferAdapter and setting that instead. As a result, mAdapter is not set to any RecyclerView and updating it does nothing.

Change this part of your code:

mTransferRecyclerView.setAdapter(new TransferAdapter(transfers));

to

mTransferRecyclerView.setAdapter(mAdapter);

P.S. I would actually suggest you to remove List<Transfer> transfers from constructor of your TransferAdapter class and initialize your field private List<Transfer> mTransfers; to empty list. Then after inflating views create an instance of adapter and set it to RecyclerView immediately. When data is ready later you can call your setTransfers method and notify adapter.

Upvotes: 1

iCantC
iCantC

Reputation: 3180

I think it should be implemented this way

public void setTransfers(List<Transfer> transfers) {
            mTransfers.clear() //clear the old data
            Collections.copy(mTransfers, transfers) //copy the new data to old empty list
        }

Upvotes: 0

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