How to Create Simple Calculator application in android studio

Hello android developer. today I will tell you how to make a simple calculator app using android studio. By using my simple calculator source code, you can create a simple calculator app, simply copy the code and paste it in android studio and you can easily create a simple calculator app. Source code is provided below you can copy it and use it or you can use your creativity to add some extra features to it.

XML (activity_main.xml)

<android.support.constraint.ConstraintLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    xmlns:tools="http://schemas.android.com/tools"
    tools:context=".Basic_calculator">

    <EditText
        android:id="@+id/textinput1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentEnd="true"
        android:layout_alignParentLeft="true"
        android:layout_alignParentRight="true"
        android:layout_alignParentStart="true"
        android:layout_alignParentTop="true"

        android:ems="10"
        android:inputType="numberSigned"
        app:layout_constraintBottom_toTopOf="@+id/textinput2"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <EditText
        android:id="@+id/textinput2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentEnd="true"
        android:layout_alignParentLeft="true"
        android:layout_alignParentRight="true"
        android:layout_alignParentStart="true"
        android:layout_below="@+id/textinput1"

        android:ems="10"
        android:inputType="numberSigned"
        app:layout_constraintBottom_toTopOf="@+id/output"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/textinput1" />

    <TextView
        android:id="@+id/output"
        android:layout_width="210dp"
        android:layout_height="24dp"
        android:layout_alignParentEnd="true"
        android:layout_alignParentLeft="true"
        android:layout_alignParentRight="true"
        android:layout_alignParentStart="true"
        android:layout_below="@+id/textinput2"
        android:layout_marginBottom="8dp"

        android:text=""
        android:textColor="#000000"
        app:layout_constraintBottom_toTopOf="@+id/buttonSub"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/textinput2" />

    <Button
        android:id="@+id/buttonAdd"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentEnd="true"
        android:layout_alignParentLeft="true"
        android:layout_alignParentRight="true"
        android:layout_alignParentStart="true"
        android:layout_below="@+id/output"
        android:onClick="doAdd"
        android:text="Add"
        android:textStyle="bold"
        app:layout_constraintBottom_toTopOf="@+id/buttonDivide"
        app:layout_constraintEnd_toStartOf="@+id/buttonSub"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/output" />

    <Button
        android:id="@+id/buttonSub"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentEnd="true"
        android:layout_alignParentLeft="true"
        android:layout_alignParentRight="true"
        android:layout_alignParentStart="true"
        android:layout_below="@+id/buttonAdd"
        android:onClick="doSub"
        android:text="Subtract"
        android:textStyle="bold"
        app:layout_constraintBottom_toTopOf="@+id/buttonMulty"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toEndOf="@+id/buttonAdd"
        app:layout_constraintTop_toBottomOf="@+id/output" />

    <Button
        android:id="@+id/buttonMulty"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentEnd="true"
        android:layout_alignParentLeft="true"
        android:layout_alignParentRight="true"
        android:layout_alignParentStart="true"
        android:layout_below="@+id/buttonSub"
        android:onClick="doMulty"
        android:text="Multiply"
        android:textStyle="bold"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toEndOf="@+id/buttonDivide"
        app:layout_constraintTop_toBottomOf="@+id/buttonSub" />

    <Button
        android:id="@+id/buttonDivide"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentEnd="true"
        android:layout_alignParentLeft="true"
        android:layout_alignParentRight="true"
        android:layout_alignParentStart="true"
        android:layout_below="@+id/buttonMulty"
        android:onClick="doDivide"
        android:text="Divide"
        android:textStyle="bold"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toStartOf="@+id/buttonMulty"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/buttonAdd" />
    </android.support.constraint.ConstraintLayout>

JAVA (MainActivity.java)

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.EditText;
import android.widget.TextView;

public class Basic_calculator extends AppCompatActivity {

    EditText text1,text2;
    TextView output;

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

        text1=(EditText)findViewById(R.id.textinput1);
        text2=(EditText)findViewById(R.id.textinput2);
        output=(TextView) findViewById(R.id.output);
    }
    public void doAdd(View v)
    {
        try
        {
            int a=Integer.parseInt("" + text1.getText());
            int b=Integer.parseInt("" + text2.getText());
            int sum=a+b;
            output.setText("" + sum);
        }
        catch (Exception ex)
        {
            System.out.println(ex);
            output.setText(ex.getMessage());
        }
    }
    public void doSub(View v)
    {
        try
        {
            int a=Integer.parseInt("" + text1.getText());
            int b=Integer.parseInt("" + text2.getText());
            int sub=a-b;
            output.setText("" + sub);
        }
        catch (Exception ex)
        {
            System.out.println(ex);
            output.setText(ex.getMessage());
        }
    }
    public void doMulty(View v)
    {
        try
        {
            int a=Integer.parseInt("" + text1.getText());
            int b=Integer.parseInt("" + text2.getText());
            int mul=a*b;
            output.setText("" + mul);
        }
        catch (Exception ex)
        {
            System.out.println(ex);
            output.setText(ex.getMessage());
        }
    }
    public void doDivide(View v)
    {
        try
        {
            int a=Integer.parseInt("" + text1.getText());
            int b=Integer.parseInt("" + text2.getText());
            int div=a/b;
            output.setText("" + div);
        }
        catch (Exception ex)
        {
            System.out.println(ex);
            output.setText(ex.getMessage());
        }
    }

}