code for app

package com.example.myapplication;

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;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {

//    declare variables first
    EditText number1,number2;
    Button addtionbtn;
    TextView result;

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

//        getting resource by their id's
        number1 = findViewById(R.id.et_number1);
        number2 = findViewById(R.id.et_number2);
        addtionbtn = findViewById(R.id.btn_addition);
        result = findViewById(R.id.tv_result);



    }

//    this function will be called after clicking on the button
    public void addition(View view) {

//        converting edit text to string type
//        getText() method is used to get the text
//        toString() method is used to convert that text into string

       String num1 =  number1.getText().toString();
       String num2 =  number2.getText().toString();

//      converting variables into double
        double doublenumber1 = Double.parseDouble(num1);
        double doublenumber2 = Double.parseDouble(num2);

//        showing text into textView
        result.setText(Double.toString(doublenumber1+doublenumber2));

//        creating Toast
        Toast.makeText(this,"Your addition is :"+(doublenumber1+doublenumber2),Toast.LENGTH_LONG).show();





    }
}