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Looking for some help to see what I'm doing wrong with this code. I'm stock and been at it for a while now. This example started from here.

Simple Android grid example using RecyclerView with GridLayoutManager (like the old GridView)

Gradle

 implementation 'com.squareup.picasso:picasso:2.71828'

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">

<android.support.v7.widget.RecyclerView
 android:id="@+id/rvNumbers"
 android:layout_width="match_parent"
 android:layout_height="match_parent"
 android:scrollbars="vertical"/>

</android.support.constraint.ConstraintLayout>

recyclerview_item.xml

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="horizontal"
android:padding="5dp"
android:layout_width="50dp"
android:layout_height="50dp">

<ImageView
 android:id="@+id/info_text"
 android:layout_width="match_parent"
 android:layout_height="match_parent"
 android:gravity="center"
 android:background="@color/colorAccent" />

</android.support.constraint.ConstraintLayout>

MainActivity

public class MainActivity extends AppCompatActivity implements 
MyRecyclerViewAdapter.ItemClickListener 

MyRecyclerViewAdapter adapter;


@Override
protected void onCreate(Bundle savedInstanceState) 
 super.onCreate(savedInstanceState);
 setContentView(R.layout.activity_main);

 // data to populate the RecyclerView with
 String data = "1", "2", "3", "4", "5", "6", "7", "8", "9", "10", 
"11", "12", "13", "14", "15", "16", "17", "18", "19", "20", "21", "22", 
"23", "24", "25", "26", "27", "28", "29", "30", "31", "32", "33", "34", 
"35", "36", "37", "38", "39", "40", "41", "42", "43", "44", "45", "46", 
"47", "48";

 // set up the RecyclerView
 RecyclerView recyclerView = findViewById(R.id.rvNumbers);
 int numberOfColumns = 6;
 recyclerView.setLayoutManager(new GridLayoutManager(this, 
 numberOfColumns));
 adapter = new MyRecyclerViewAdapter(this, data);
 adapter.setClickListener(this);
 recyclerView.setAdapter(adapter);


@Override
public void onItemClick(View view, int position) 
 Log.i("TAG", "You clicked number " + adapter.getItem(position) + ", 
 which is at cell position " + position);

MyRecyclerViewAdapter

import android.content.Context;
import android.support.annotation.NonNull;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;

import com.squareup.picasso.Picasso;

public class MyRecyclerViewAdapter extends 
RecyclerView.Adapter<MyRecyclerViewAdapter.ViewHolder> 

private String mData;
private LayoutInflater mInflater;
private ItemClickListener mClickListener;
private Context context;


// data is passed into the constructor
MyRecyclerViewAdapter(Context context, String data) 
 this.mInflater = LayoutInflater.from(context);
 this.mData = data;


// inflates the cell layout from xml when needed
@Override
@NonNull
public ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int 
viewType) 
 View view = mInflater.inflate(R.layout.recyclerview_item, parent, 
false);
 return new ViewHolder(view);





// binds the data to the TextView in each cell
@Override
public void onBindViewHolder(@NonNull ViewHolder holder, int position) 
 Picasso.get()
 .load(R.drawable.androidvsapple)
 .into(holder.myImageView);


// total number of cells
@Override
public int getItemCount() 
 return mData.length;



// stores and recycles views as they are scrolled off screen
public class ViewHolder extends RecyclerView.ViewHolder implements 
View.OnClickListener 

 ImageView myImageView;

 ViewHolder(View itemView) 
 super(itemView);


 myImageView = itemView.findViewById(R.id.info_text);
 itemView.setOnClickListener(this);

 

 @Override
 public void onClick(View view) 
 if (mClickListener != null) mClickListener.onItemClick(view, 
getAdapterPosition());
 



String getItem(int id) 
 return mData[id];



void setClickListener(ItemClickListener itemClickListener) 
 this.mClickListener = itemClickListener;


// parent activity will implement this method to respond to click events
public interface ItemClickListener 
 void onItemClick(View view, int position);

}