How to perform this date update on my RecyclerView rows?

Question

In my RecyclerView adapter, my rows have TextViews that display dates. If the user clicks the TextView, a DialogFragment is displayed that lets the user pick a time and date, and then a Date is passed back through an interface.

However I don't know how to grab the date back in the onClick method I added to my TextView.

public class RecyclerViewHolder extends RecyclerView.ViewHolder {
        public TextView dateTextView;
        public RecyclerViewHolder(View itemView) {
            super(itemView);
            dateTextView = (TextView) itemView.findViewById(R.id.date_textview);

            dateTextView.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    //I can call my DialogFragment here but then what?
                }
            });

Answer 1

You can create an interface to communicate with adapter:

public class RecyclerViewHolder extends RecyclerView.ViewHolder {

    public TextView dateTextView;
    private IAdapter adapter;

    public RecyclerViewHolder(View itemView, IAdapter adapter) {
        super(itemView);
        dateTextView = (TextView) itemView.findViewById(R.id.date_textview);
        this.adapter = adapter;

        dateTextView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                MyDialogFragment fragment = MyDialogFragment.newInstance(getAdapterPosition(), adapter);
                FragmentTransaction ft = v.getContext().getFragmentManager().beginTransaction();
                fragment.show(ft, "calendarDialog");
            }
        });
    }
}

The interface which the adapter will need to implement is:

interface IAdapter extends Serializable {
    void setDataAt(int index, Calendar date);
    void notifyItemChanged(int index);
}

Since adapter already has the notifyItemChanged method, you will only need to implement the setDataAt method.

Assuming that your Adapter will only contain dates, here is an example:

public class RecyclerViewAdapter extends RecyclerView.Adapter<RecyclerViewHolder> implements IAdapter {

    private List<Calendar> dates = new ArrayList<>();

    public RecyclerViewAdapter(List<Calendar> dates) {
        this.dates = dates;
    }

    @Override
    public void setDataAt(int index, Calendar date) {
        dates.add(index, date);
    }

    @Override
    public RecyclerViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        LayoutInflater inflater = LayoutInflater.from(parent.getContext());
        View holderView = inflater.inflate(R.layout.view_holder, parent, false);
        return new RecyclerViewHolder(holderView, this); // notice how we pass this adapter's interface along with the view
    }

    // Include other methods (getItemCount, onBindViewHolder, etc.)
    // Adapter already has the notifyItemChanged(int index) method so no need to override it
}

Here is an example of a DialogFragment that uses the index position and a Calendar object:

public static class MyDialogFragment extends DialogFragment {
    private int index;
    private IAdapter adapter;


    public static MyDialogFragment newInstance(int index, IAdapter adapter) {
        MyDialogFragment f = new MyDialogFragment();

        Bundle args = new Bundle();
        args.putInt("index", index);
        args.putSerializable("adapter", adapter);
        f.setArguments(args);

        return f;
    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        Bundle args = getArguments();
        index = args.getInt("index");
        adapter = args.getSerializable("adapter");
    }

    // Build view and set OnClickListener for setting date
}

After the user updates the date, invoke the following:

adapter.setDataAt(index, date);
adapter.notifyItemChanged(index);