如何检查RecyclerView适配器中的每个值？

Question

I have a custom RecyclerView adapter that I instantiate from my onCreate method that contains 9 fixed data points:

    GridRecyclerAdapter adapter;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        ...

        /* Dummy cell data */
        String[] data = {"", "", "", "", "", "", "", "", ""};

        ...

        /* Init RecyclerView */
        RecyclerView recyclerView = (RecyclerView) findViewById(R.id.recyclerView);
        int numColumns = 3;
        recyclerView.setLayoutManager(new GridLayoutManager(this, numColumns));
        adapter = new GridRecyclerAdapter(this, data, numColumns, player1, player2);
        adapter.setClickListener(this);
        recyclerView.setAdapter(adapter);
    }

The clickListener in my ViewHolder sets the text to "X" when clicked.

    class ViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {
        TextView cellTextView;

        ViewHolder(View itemView) {
            super(itemView);
            cellTextView = (TextView) itemView.findViewById(R.id.textView);
            itemView.setOnClickListener(v -> {
                /* Set cell TextView to "X" */
                cellTextView.setText("X");
            });
        }
    }

On each click, I want to check if a certain combination of itemViews posses a certain value. For example, if itemViews with positions 1, 2 and 3 have a TextView equal to "X", then show an AlertDialog. I imagine I should be able to modify the String[] I passed in the constructor with each click.

Answer 1

1. Extract the setOnClickListener from your ViewHolder and move it to your Adapter's onBindViewHolder .
2. Keep the checked positions in some form (eg an array of integers)
3. When you set X on one of your Views see if the change in the checked positions is valid for showing your AlertDialog

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

    List<Integer> xPositions = new ArrayList<>();

    // ... all the needed stuff.

    @Override
    public void onBindViewHolder(final ViewHolder holder, int position) {
        holder.itemView.setOnClickListener(v -> {
            holder.showX();
            xPositions.add(holder.getAdapterPosition());
            checkIfShouldShowAlert();
        });
    }

    void checkIfShouldShowAlert() {
        // do your checks on xPositions and show the AlertDialog if needed
    }

    public static class ViewHolder extends RecyclerView.ViewHolder {
        TextView cellTextView;

        ViewHolder(View itemView) {
            super(itemView);
            cellTextView = (TextView) itemView.findViewById(R.id.textView);
        }

        void showX(){
            cellTextView.setText("X");
        }
    }
}

Remember to add a mechanism that would prevent consecutive clicks on the same views (otherwise the xPositions array would grow and grow).