cannot resolve symbol findViewById in class with extends RecyclerView.Adapter<RecyclerViewAdapter.ViewHolder>

Question

this my class

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

and I tried declaration foto = (ImageView) findViewById(R.id.Foto); in method @Override public void onBindViewHolder(ViewHolder Viewholder, int position) {

and I tried to use protected void onCreate(Bundle savedInstanceState) { but it's still error

adapter class

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

    Context context;
    private static final String TAG = RecyclerViewAdapter.class.getSimpleName();

    List<GetDataAdapter> getDataAdapter;

    ImageLoader imageLoader1;
    private ImageView foto;
    String getFoto;
    String FIXURL = "http://192.168.0.103/AndroidFileUpload/";
    String url = FIXURL + "uploads/";


    public RecyclerViewAdapter(List<GetDataAdapter> getDataAdapter, Context context) {

        super();
        this.getDataAdapter = getDataAdapter;
        this.context = context;
    }

    @Override
    public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {

        View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.recyclerview_items, parent, false);

        ViewHolder viewHolder = new ViewHolder(v);

        return viewHolder;
    }

    @Override
    public void onBindViewHolder(ViewHolder Viewholder, int position) {

        final GetDataAdapter getDataAdapter1 = getDataAdapter.get(position);

        imageLoader1 = ServerImageParseAdapter.getInstance(context).getImageLoader();

//        imageLoader1.get(getDataAdapter1.getFoto(),
//                ImageLoader.getImageListener(
//                        Viewholder.networkImageView,//Server Image
//                        R.mipmap.ic_launcher,//Before loading server image the default showing image.
//                        android.R.drawable.ic_dialog_alert //Error image if requested image dose not found on server.
//                )
//        );
//        getFoto = getDataAdapter1.getIdJalan();;
//        String FullURL = url+getFoto;
        foto = (ImageView) findViewById(R.id.Foto);
//        Picasso.with(getApplicationContext()).load(url + getDataAdapter1.getFoto()).into(foto);

        Viewholder.networkImageView.setImageUrl(getDataAdapter1.getFoto(), imageLoader1);

        Viewholder.ImageTitleNameView.setText(getDataAdapter1.getIdJalan());

        Viewholder.itemView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Log.d(TAG, "coba nih5 : "+getDataAdapter1.getIdJalan());
//
//                Intent intent = new Intent(v.getContext(), SeconActivity.class);
//                intent.putExtra("key",getDataAdapter1.getImageTitleName());// getDataAdapter1 in your case
//                context.startActivity(intent);
            }
        });

    }

    @Override
    public int getItemCount() {

        return getDataAdapter.size();
    }

    class ViewHolder extends RecyclerView.ViewHolder{

        public TextView ImageTitleNameView;
        public NetworkImageView networkImageView;

        public ViewHolder(View itemView) {

            super(itemView);

            ImageTitleNameView = (TextView) itemView.findViewById(R.id.textView_item);

            networkImageView = (NetworkImageView) itemView.findViewById(R.id.VollyNetworkImageView1);
        }


    }
}

this is the layout

<?xml version="1.0" encoding="utf-8"?>
<android.support.v7.widget.CardView
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:card_view="http://schemas.android.com/apk/res-auto"
    android:id="@+id/cardview1"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    card_view:cardElevation="3dp"
    card_view:contentPadding="3dp"
    card_view:cardCornerRadius="3dp"
    card_view:cardMaxElevation="3dp"
    >


    <RelativeLayout
        android:layout_width="fill_parent"
        android:layout_height="wrap_content">

        <de.hdodenhof.circleimageview.CircleImageView
            android:id="@+id/Foto"
            android:layout_width="100dp"
            android:layout_height="100dp"
            android:src="@mipmap/ic_launcher"/>

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textAppearance="?android:attr/textAppearanceLarge"
            android:text="Image Name"
            android:id="@+id/textView_item"
            android:layout_centerVertical="true"
            android:layout_toRightOf="@+id/VollyNetworkImageView1"
            android:layout_toEndOf="@+id/VollyNetworkImageView1"
            android:layout_marginLeft="20dp"/>

    </RelativeLayout>

    </android.support.v7.widget.CardView>

Answer 1

This error means that you are using the wrong object to call findViewById() . You must use an Activity or a View to call this method. Most likely you need to obtain the view from the ViewHolder which is passed to the onBindViewHolder() method. Something like this

View v = viewholder.itemView;
foto = (ImageView) v.findViewById(R.id.Foto);

ps The declaration ViewHolder Viewholder is incredibly confusing. Usually variable names start with lower case. Better yet, use a significantly different word such as ViewHolder holder . This makes it clear what the type and name are without needing to look so closely at the exact letters and case.