Android Recyclerview GridLayoutManager column spacing

This example demonstrates about Android Recyclerview GridLayoutManager column spacing
Step 1 − Create a new project in Android Studio, go to File ⇒ New Project and fill all required details to create a new project.
Step 2 − Add the following code to res/layout/activity_main.xml.
<?xml version = "1.0" encoding = "utf-8"?>
<android.support.design.widget.CoordinatorLayout android:layout_width = "match_parent"
   android:layout_height = "match_parent"
   xmlns:android = "http://schemas.android.com/apk/res/android"
   xmlns:app = "http://schemas.android.com/apk/res-auto">
   <android.support.design.widget.AppBarLayout
      android:layout_width = "match_parent"
      android:layout_height = "wrap_content">
      <android.support.v7.widget.Toolbar
         android:id = "@+id/appbarlayout_tool_bar"
         android:background = "@color/colorPrimary"
         android:layout_width = "match_parent"
         android:layout_height = "?attr/actionBarSize"
         app:layout_scrollFlags = "scroll|snap|enterAlways"
         app:theme = "@style/ThemeOverlay.AppCompat.Dark.ActionBar"
         app:popupTheme = "@style/ThemeOverlay.AppCompat.Light" />
   </android.support.design.widget.AppBarLayout>
   <android.support.v7.widget.RecyclerView
      android:id = "@+id/recycler_view"
      android:layout_width = "match_parent"
      android:layout_height = "match_parent"
      app:layout_behavior = "@string/appbar_scrolling_view_behavior"/>
</android.support.design.widget.CoordinatorLayout>
In the above code, we have taken recyclerview.
Step 3 − Add the following code to src/MainActivity.java
package com.example.myapplication;
import android.annotation.TargetApi;
import android.os.Build;
import android.os.Bundle;
import android.support.v4.content.ContextCompat;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.DefaultItemAnimator;
import android.support.v7.widget.DividerItemDecoration;
import android.support.v7.widget.GridLayoutManager;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.support.v7.widget.Toolbar;
import android.widget.TextView;
import android.widget.Toast;
import java.util.ArrayList;
public class MainActivity extends AppCompatActivity {
   TextView text;
   ArrayList<String> list = new ArrayList<>();
   private RecyclerView recyclerView;
   private customAdapter mAdapter;
   private onClickInterface onclickInterface;
   @TargetApi(Build.VERSION_CODES.LOLLIPOP)
   @Override
   public void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.activity_main);
      Toolbar toolbar = (android.support.v7.widget.Toolbar) findViewById(R.id.appbarlayout_tool_bar);
      toolbar.setTitle("This is toolbar.");
      setSupportActionBar(toolbar);
      onclickInterface = new onClickInterface() {
         @Override
         public void setClick(int abc) {
            list.remove(abc);
            Toast.makeText(MainActivity.this,"Position is"+abc,Toast.LENGTH_LONG).show();
            mAdapter.notifyDataSetChanged();
         }
      };
      recyclerView = (RecyclerView) findViewById(R.id.recycler_view);
      GridLayoutManager mLayoutManager = new GridLayoutManager(getApplicationContext(),2);
      recyclerView.setLayoutManager(mLayoutManager);
      recyclerView.setItemAnimator(new DefaultItemAnimator());
      mAdapter = new customAdapter(this, list, onclickInterface);
      recyclerView.setAdapter(mAdapter);
      recyclerView.addItemDecoration(new SpacesItemDecoration(10));
      list.add("sairamm");
      list.add("Krishna");
      list.add("prasad");
      list.add("sairamm");
      list.add("Krishna");
      list.add("prasad");
      list.add("sairamm");
      list.add("Krishna");
      list.add("prasad");
      list.add("sairamm");
      list.add("Krishna");
      list.add("prasad");
      list.add("Krishna");
      list.add("prasad");
      list.add("sairamm");
      list.add("Krishna");
      list.add("prasad");
      list.add("sairamm");
      list.add("Krishna");
      list.add("prasad");
   }
}
Step 4 − Add the following code to src/ customAdapter.java
package com.example.myapplication;
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.TextView;
import java.util.ArrayList;
public class customAdapter extends RecyclerView.Adapter<customAdapter.MyViewHolder> {
   Context context;
   ArrayList<String> list;
   onClickInterface onClickInterface;
   public class MyViewHolder extends RecyclerView.ViewHolder {
      public TextView title;
      public MyViewHolder(View view) {
         super(view);
         title = (TextView) view.findViewById(R.id.title);
      }
   }
   public customAdapter(Context context, ArrayList<String> list, onClickInterface onClickInterface) {
      this.context = context;
      this.list = list;
      this.onClickInterface = onClickInterface;
   }
   @NonNull
   @Override
   public MyViewHolder onCreateViewHolder(@NonNull ViewGroup viewGroup, int i) {
      View itemView = LayoutInflater.from(viewGroup.getContext()).inflate(R.layout.list_row, viewGroup, false);
      return new MyViewHolder(itemView);
   }
   @Override
   public void onBindViewHolder(@NonNull MyViewHolder myViewHolder, final int i) {
      myViewHolder.title.setText(list.get(i));
      myViewHolder.title.setOnClickListener(new View.OnClickListener() {
         @Override
         public void onClick(View v) {
            onClickInterface.setClick(i);
         }
      });
   }
   @Override
   public int getItemCount() {
      return list.size();
   }
}
Step 5 − Add the following code to res/layout/ list_row.xml.
<?xml version = "1.0" encoding = "utf-8"?>
<android.support.v7.widget.CardView xmlns:android = "http://schemas.android.com/apk/res/android"
   xmlns:app = "http://schemas.android.com/apk/res-auto"
   xmlns:tools = "http://schemas.android.com/tools"
   android:layout_width = "match_parent"
   android:layout_height = "wrap_content"
   app:cardElevation = "10dp"
   app:cardCornerRadius = "20dp"
   tools:context = ".MainActivity">
   <LinearLayout
      android:layout_width = "match_parent"
      android:layout_height = "wrap_content"
      android:gravity = "center"
      android:orientation = "vertical">
      <ImageView
         android:id = "@+id/imageView2"
         android:layout_width = "wrap_content"
         android:layout_height = "wrap_content"
         android:src = "@drawable/logo" />
      <TextView
         android:id = "@+id/title"
         android:layout_width = "match_parent"
         android:layout_height = "wrap_content"
         android:gravity = "center"
         android:textSize = "30sp" />
      <TextView
         android:id = "@+id/textview2"
         android:layout_width = "match_parent"
         android:layout_height = "wrap_content"
         android:gravity = "center"
         android:text = "Sairamkrishan"
         android:textSize = "30sp" />
   </LinearLayout>
</android.support.v7.widget.CardView>
Step 6 − Add the following code to src/ onClickInterface.
package com.example.myapplication;
public interface onClickInterface {
   void setClick(int abc);
}
Step 7 − Add the following code to src/ SpacesItemDecoration.java.
package com.example.myapplication;
import android.graphics.Rect;
import android.support.v7.widget.RecyclerView;
import android.view.View;
public class SpacesItemDecoration extends RecyclerView.ItemDecoration {
   private int space;
   public SpacesItemDecoration(int space) {
      this.space = space;
   }
   @Override
   public void getItemOffsets(Rect outRect, View view, RecyclerView parent, RecyclerView.State state) {
      outRect.left = space;
      outRect.right = space;
      outRect.bottom = space;
      // Add top margin only for the first item to avoid double space between items
      if (parent.getChildLayoutPosition(view) = = 0) {
         outRect.top = space;
      } else {
         outRect.top = 0;
      }
   }
}
Let's try to run your application. I assume you have connected your actual Android Mobile device with your computer. To run the app from an android studio, open one of your project's activity files and click Run  icon from the toolbar. Select your mobile device as an option and then check your mobile device which will display your default screen -