Creating a simple android application

 MainActivity.java

package com.example.whoami;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;



/* Interface is used for Reusability */

// Overloading - same method different paramters within the class
// Overriding  - same method different class used in inheritance


// Activity Life Cycle
// on , Pause , oncreate, ondestroy


public class MainActivity extends AppCompatActivity {

    TextView result;
    TextView result2;
    Button btn;
    EditText num1field;
    EditText num2field;

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

        num1field = (EditText)findViewById(R.id.num1);
        num2field = (EditText)findViewById(R.id.num2);
        btn = (Button)findViewById(R.id.btn);
        result = (TextView)findViewById(R.id.result);




        btn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                // On click  Handling
                int n1 = Integer.parseInt(num1field.getText().toString());
                int n2 = Integer.parseInt(num2field.getText().toString());
                String greater;
                if (n1>n2){
                    greater = n1 +" is greater than "+ n2;
                }
                else{
                    greater = n2 +" is greater than "+ n1;
                }
                result.setText(greater);

            }
        });

    }
}

Activity main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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="match_parent"
    android:orientation="vertical"
    tools:context=".MainActivity">

    <EditText
        android:id="@+id/num1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:ems="10"
        android:hint="Enter first number"
        android:inputType="numberSigned" />

    <EditText
        android:id="@+id/num2"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:ems="10"
        android:hint="Enter second number"
        android:inputType="numberSigned" />

    <Button
        android:id="@+id/btn"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Button" />

    <TextView
        android:id="@+id/result"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="TextView" />

    <TextView
        android:id="@+id/result2"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="TextView" />


</LinearLayout>