Android Application to Add Two Numbers

Last Updated : 06 Jan, 2025

Below are the steps for Creating a Simple Android Application to Add Two Numbers

Note: Similarly, Android App to subtract, multiply and divide numbers can be made by making minor changes in the Java and XML code.

Step-by-Step Implementation of Application to Add Two Numbers in Android

Step 1: Opening/Creating a New Project

To create a new project in Android Studio please refer to How to Create/Start a New Project in Android Studio.

Note: Select Java as the programming language.

By default, there will be two files activity_main.xml and MainActivity.java.

Step 2: Now go to the activity_main.xml file and Add elements to the layout

Here, we are using constrainLayout in our application where we will be using Constraints and Chaining concepts.

Navigate to activity_main.xml file:

Complete code of layout xml file is mentioned below:

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout 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:id="@+id/main"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <TextView
        android:id="@+id/textView1"
        android:layout_width="150dp"
        android:layout_height="48dp"
        android:layout_marginStart="10dp"
        android:layout_marginTop="52dp"
        android:gravity="center_vertical"
        android:text="@string/first_textView"
        android:textSize="16sp"
        app:layout_constraintEnd_toStartOf="@+id/first_number"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <EditText
        android:id="@+id/first_number"
        android:layout_width="150dp"
        android:layout_height="48dp"
        android:layout_marginTop="52dp"
        android:ems="10"
        android:hint="@string/first_number_hint"
        android:inputType="number"
        android:textSize="16sp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toEndOf="@+id/textView1"
        app:layout_constraintTop_toTopOf="parent" />

    <TextView
        android:id="@+id/textView2"
        android:layout_width="150dp"
        android:layout_height="48dp"
        android:layout_marginStart="10dp"
        android:layout_marginTop="8dp"
        android:gravity="center_vertical"
        android:text="@string/second_textView"
        android:textSize="16sp"
        app:layout_constraintEnd_toStartOf="@+id/second_number"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/textView1" />

    <EditText
        android:id="@+id/second_number"
        android:layout_width="175dp"
        android:layout_height="48dp"
        android:layout_marginTop="4dp"
        android:layout_marginEnd="10dp"
        android:ems="10"
        android:hint="@string/second_number_hint"
        android:inputType="number"
        android:textSize="16sp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toEndOf="@+id/textView2"
        app:layout_constraintTop_toBottomOf="@+id/first_number" />

    <Button
        android:id="@+id/button"
        android:layout_width="139dp"
        android:layout_height="57dp"
        android:layout_marginTop="84dp"
        android:text="@string/Button_value"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/textView2" />


    <TextView
        android:id="@+id/result"
        android:layout_width="150dp"
        android:layout_height="40dp"
        android:layout_marginTop="88dp"
        android:gravity="center"
        android:text="@string/result"
        android:textSize="16sp"
        android:visibility="gone"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toStartOf="@+id/result_value"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/button"
        app:layout_constraintVertical_bias="0.006" />

    <TextView
        android:id="@+id/result_value"
        android:layout_width="150dp"
        android:layout_height="40dp"
        android:gravity="center"
        android:textSize="16sp"
        android:visibility="gone"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toEndOf="@+id/result"
        app:layout_constraintTop_toTopOf="@+id/result" />

</androidx.constraintlayout.widget.ConstraintLayout>

After Complete layout xml file it will be shown as given below :

Note: The Layout of Android Application differ for all. Although the elements will be same for all.

Step 3: Now, open up the activity java file.

Navigate to MainActivity.java file is mentioned below:

Step 4: Changes are done in Java MainActivity file

Declare a few variables and the values entered in the Text Views can be read by using an id which we have set in the XML code above.
Add the click listener to the Add button.
When the Add button has been clicked, add the values and store them in the sum variable.
To show the output in the result text view, set the sum in the TextView.

Complete code of layout xml file and java file is given below.

package org.geeksforgeeks.add_two_numbers;

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

import androidx.appcompat.app.AppCompatActivity;

public class MainActivity extends AppCompatActivity {

      // Variables
    EditText number1,number2;
    Button Add_button;
    TextView temp,result;
    int ans=0;

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

          // Assiging the values to variables
        number1=(EditText) findViewById(R.id.first_number);
        number2=(EditText) findViewById(R.id.second_number);
        Add_button=(Button) findViewById(R.id.button);
        result=(TextView) findViewById(R.id.result_value);
        temp=(TextView) findViewById(R.id.result);

        Add_button.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v){
                double num1 = Double.parseDouble(number1.getText().toString());
                double num2 = Double.parseDouble(number2.getText().toString());
                // add both number and store it to sum
                double sum = num1 + num2;
                // set it ot result textviewe
                result.setText(Double.toString(sum));

                temp.setVisibility(View.VISIBLE);
                result.setVisibility(View.VISIBLE);
            }
        });
    }
}