Calling Fragment method from attached RecyclerView.Adapter

Question

I recently started coding my first Android project using Android Studio 3.1.2 and SDK 19.

One of my fragments contains a RecyclerView with a custom RecyclerView.Adapter attached. On the CardView the Adapter gets by its ViewHolder, there can be a button. The target is, if the button is pressed, a method of my fragment should be called, though it's an instance of a custom subclass of Fragment:

From RequestingFragment:

public abstract class RequestingFragment extends Fragment implements RequestCallbacks {

    public final static void startRequest(final RequestOperation, String param) {
        //this is the guy i want to call
    }

    //these are the RequestCallbacks, they're all getting called in startRequest()
    public void onSuccess(JSONObject json, String parsingkey) { }

    public void onError() { }

    public void onFinished() { }

Now one of my RequestingFragments contains a RecyclerView, on which a custom ErrorCompactAdapter is attached. Inside the Adapters ViewHolder, where I load the layout for the single CardViews, there's a button, which should call startRequest() onClick from my RequestingFragment

From ErrorCompactAdapter:

public class ErrorCompactAdapter extends RecyclerView.Adapter<ErrorCompactAdapter.ErrorCompactViewHolder> {

    private Context context;
    private ArrayList<Error> errors;

    public ErrorCompactAdapter(Context context, ArrayList<Error> errors) {
        this.context = context;
        this.errors = errors;
    }
    
    public void onBindViewHolder(ErrorCompactViewHolder, int position) {
        //...
        holder.errorTakeOverButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                //here's were i'm stuck
            }
        });
        //...
    }
}

My first approach was to change the context attribute of ErrorCompactAdapter to a RequestingFragment, so that I can call startRequest() on this.

private Context context; // private RequestingFragment attacher;

public void onClick(View v) {
    attacher.startRequest(/*params*/);
}

But i'm very unsure, if the fragment that contains the RecyclerView will be the one which receives the response of the request, or if a somehow "pseudo-anonymous" Fragment will receive the response and simply does nothing with it then. Can someone enlight me, if this is the correct path? Thanks in advance.

Answer 1

Pass the Fragment in you ErrorCompactAdapter class's constructor. This works for me the way I want. I had the same issue.

RequestingFragment mFragment;

public ErrorCompactAdapter(Context context, ArrayList<Error> errors, 
                           RequestingFragment fragment) 
{
    this.context = context;
    this.errors = errors;
    this.mFragment = fragment;
}

// While passing the fragment into your adapter, do it this way.

ErrorCompactAdapter errorCompactAdapter = new ErrorCompactAdapter(
          context, errors, RequestingFragment.this);

holder.errorTakeOverButton.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View v) {
        // use you method of fragment here
        mFragment.startRequest();
    }
});