How to pass a Recycler view adapter in a constructor?

Question

Let's say I have three Adapter like this and each has an interface defined in them ie ClickListener which has a method onItemClick.

public class SearchResultAdapter extends RecyclerView.Adapter<SearchResultAdapter.searchResultViewHolder> 
{

....
public interface ClickListener {
    void onItemClick(int paramInt, View paramView);
}

}

How to pass the adapters to the constructor so I can get access to the ClickListener() method adapter inside the class.

Example

public class ABC{

private RecyclerView.Adapter adapter;

public ABC(RecyclerView.Adapter adapter){
this.adapter = adapter;
}

private void xyz(){

//How to achieve this
recyclerView.setOnClickListener(new adapter.ClickListener(){

@Override
        public void onItemClick(int position, View v) {

        }
    });   

}

Answer 1

Well, in your Activity/Fragment, you have the RecyclerView instance, in there, you should be able to pass to ABC the Recycler so it can attach the onClick.

But, what I would recommend for a better design is: Your activity/Fragment implements your adapter OnClickListener as: Receive the click and pass it to ABC, and then ABC handle it.

Like:

public class SearchResultAdapter extends RecyclerView.Adapter<SearchResultAdapter.searchResultViewHolder> 
{

public void setListener(ClickListener listener){
    this.listener = listener;
}
public interface ClickListener {
    void onItemClick(int paramInt, View paramView);
}

}

public class ABC {
    public void adapterClicked(){
         // do something here on adapter item clicked.
    }
}

public class Activity extends AppCompatActivity {
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout....);

        SearchResultAdapter adapter = new ........();
        ABC abc = new ABC();

        adapter.setOnClickListener(() -> {
            abc.adapterClicked();
        }); // java 8
    }
}

Answer 2

I have tried below method Create an interface RecyclerOnItemClickListener

import android.view.View;

public interface RecyclerOnItemClickListener {

public void onItemClick(View childView, int position);
}

In the adapter class, you can take the RecyclerOnItemClickListener object which is implemented in the calling Activity/Fragment

RecyclerOnItemClickListener mItemClickListener;

You can then initialize that variable in the constructor of the adapter

mItemClickListener = recyclerOnItemClickListener;

The activity/Fragment implements the RecyclerOnItemClickListener interface, so it will have onItemClick method implemented. You can write the code for passing data in the next activity here

@Override
public void onItemClick(View childView, int position)
{
    Intent intent = new Intent(getActivity(), NextActivity.class);
    intent.putExtra("ITEM", mModels.get(position));
    startActivity(intent);
}

In the adapter class, you will need to initialize the ViewHolder class as shown below:

class ViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener
{
TextView content;
TextView proba;
ImageView imageView;


public ViewHolder(View itemView) {
    super(itemView);

    content = (TextView) itemView.findViewById(R.id.textView);
    proba = (TextView) itemView.findViewById(R.id.textView2);
    imageView = (ImageView) itemView.findViewById(R.id.imageView);


}

    @Override
    public void onClick(View v)
    {
        if (mItemClickListener != null)
        {
            mItemClickListener.onItemClick(v, getPosition());
        }
    }
}

Answer 3

From your program i understand that you want ClickListener on RecyclerView. This is my Adapter.

ClickListener i created in view holder class. Just implement your class with the implements View.OnClickListener .And get user click by getAdapterPosition()

class buses_list_adaptor extends RecyclerView.Adapter<buses_list_adaptor.viewholder> {
List <Detail_buses> list;

public buses_list_adaptor(List <Detail_buses> list) {
    this.list = list;
}

@Override
public buses_list_adaptor.viewholder onCreateViewHolder(ViewGroup parent, int viewType) {
    LayoutInflater layoutInflater = LayoutInflater.from(parent.getContext());
    View view = layoutInflater.inflate(R.layout.list_buses, parent, false);

    return new viewholder(view, list);
}

@Override
public void onBindViewHolder(buses_list_adaptor.viewholder holder, int position) {
    holder.bus_no.setText(list.get(position).getBus_no());
    holder.start_bustop.setText(list.get(position).getFrom());
    holder.stop_bustop.setText(list.get(position).getTo());


}

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

class viewholder extends RecyclerView.ViewHolder implements View.OnClickListener {
    TextView bus_no, start_bustop, stop_bustop;
    List <Detail_buses> list;

    public viewholder(View itemView, List <Detail_buses> list) {
        super(itemView);
        this.list = list;
        bus_no = itemView.findViewById(R.id.buses_bus_no);
        start_bustop = itemView.findViewById(R.id.buses_from_stop);
        stop_bustop = itemView.findViewById(R.id.buses_to_stop);
        itemView.setOnClickListener(this);
    }

    @Override
    public void onClick(View view) {

        Fragment fragment= new Bus_list_stp();
        Bundle bundle= new Bundle();
        bundle.putInt("position",getAdapterPosition());
        dashboardActivity.dashboardActivityOBJ.changeFragment(fragment,bundle);


    }
}

}

I hope this will works for you