appbar

activity_main.xml

xmlns:tools="http://schemas.android.com/tools"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:fitsSystemWindows="true"
android:layout_width="match_parent"
android:layout_height="match_parent">

android:id="@+id/appbar"
android:fitsSystemWindows="true"
android:layout_height="192dp"
android:layout_width="match_parent">

android:layout_width="match_parent"
android:layout_height="match_parent"
app:toolbarId="@+id/toolbar"
app:layout_scrollFlags="scroll|enterAlways|enterAlwaysCollapsed"
app:layout_scrollInterpolator="@android:anim/decelerate_interpolator"
app:contentScrim="?attr/colorPrimary">

android:id="@+id/app_bar_image"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_collapseMode="parallax"
android:src="@mipmap/ic_launcher"
android:scaleType="centerCrop" />

android:id="@+id/toolbar"
android:layout_height="?attr/actionBarSize"
android:layout_width="match_parent">

sss.xml

xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent"
android:layout_height="match_parent"
xmlns:app="http://schemas.android.com/apk/res-auto"
app:layout_behavior="@string/appbar_scrolling_view_behavior">
android:id="@+id/recyclerView"
android:layout_width="match_parent"
android:layout_height="match_parent"
/>

card.xml

xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="320dp"
android:layout_height="wrap_content"
android:layout_marginBottom="20dp"
app:cardElevation="10dp">

android:id="@+id/textView"
android:layout_width="320dp"
android:layout_height="115dp"
android:gravity="center"
android:text="TextView" />

MainActivity.java

package com.example.mmd_king75.myapplication;

import android.app.AlertDialog;
import android.app.Dialog;
import android.app.ProgressDialog;
import android.content.DialogInterface;
import android.media.MediaPlayer;
import android.os.Handler;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.support.v7.widget.GridLayoutManager;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Adapter;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.Toast;

import java.util.ArrayList;
import java.util.Timer;
import java.util.TimerTask;

public class MainActivity extends AppCompatActivity {
ArrayList user200;
RecyclerView recyclerView;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);

user200 = new ArrayList<>();
user200.add(new user("a1"));
user200.add(new user("a1dsa"));
user200.add(new user("a1"));
user200.add(new user("a1dasdsa"));
user200.add(new user("a1"));
user200.add(new user("a1"));
user200.add(new user("a21"));
user200.add(new user("a31"));
user200.add(new user("a41"));
user200.add(new user("a51"));
user200.add(new user("a61"));
user200.add(new user("a1dsa"));
user200.add(new user("a1"));
user200.add(new user("a1dasdsa"));
user200.add(new user("a1"));
user200.add(new user("a1"));
user200.add(new user("a21"));
user200.add(new user("a31"));
user200.add(new user("a41"));
user200.add(new user("a51"));
user200.add(new user("a61"));

adapter adapter200 = new adapter(user200,this);
recyclerView = findViewById(R.id.recyclerView);
recyclerView.setLayoutManager(new GridLayoutManager(this,2));
recyclerView.setAdapter(adapter200);

}

}

adapter.java

package com.example.mmd_king75.myapplication;

import android.content.Context;
import android.support.aotation.NonNull;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
import android.widget.Toast;

import java.util.ArrayList;

public class adapter extends RecyclerView.Adapter{
ArrayList user100;
Context context;

public adapter(ArrayList user100, Context context) {
this.user100 = user100;
this.context = context;
}

@NonNull
@Override
public holder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.card,null);
return new holder(view);
}

@Override
public void onBindViewHolder(@NonNull final holder holder, final int position) {
holder.textView.setText(user100.get(position).getName());
holder.textView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Toast.makeText(context, ""+user100.get(position).getName(), Toast.LENGTH_SHORT).show();
}
});
}

@Override
public int getItemCount() {
return user100.size();
}

class holder extends RecyclerView.ViewHolder {
TextView textView;
public holder(View itemView) {
super(itemView);
textView = itemView.findViewById(R.id.textView);
}
}
}

user.java

package com.example.mmd_king75.myapplication;

public class user {
String name;

public user(String name) {
this.name = name;
}

public String getName() {
return name;
}

public void setName(String name) {
this.name = name;
}
}