Android Studio hesap makinesi programı yapmak

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:padding="4dp">
    <TextView
        android:id="@+id/textResult"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerHorizontal="true"
        android:layout_marginTop="70dp"
        android:background="#008080"
        android:padding="5dp"
        android:text="Code4Example"
        android:textColor="#fff"
        android:textSize="24sp"
        android:textStyle="bold" />
    <EditText
        android:id="@+id/editSayi1"
        android:inputType="number"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_centerInParent="true" />
    <EditText
        android:id="@+id/editSayi2"
        android:inputType="number"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_below="@+id/editSayi1"
        android:layout_centerInParent="true" />
    <GridLayout
        android:layout_centerHorizontal="true"
        android:layout_centerInParent="true"
        android:layout_below="@+id/editSayi2"
        android:columnCount="2"
        android:rowCount="2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content">
        <Button
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_centerInParent="true"
            android:layout_margin="1dp"
            android:onClick="btnTopla"
            android:text="+" />
        <Button
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_centerInParent="true"
            android:layout_margin="1dp"
            android:onClick="btnCikar"
            android:text="-" />
        <Button
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_centerInParent="true"
            android:layout_margin="1dp"
            android:onClick="btnCarp"
            android:text="*" />
        <Button
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_centerInParent="true"
            android:layout_margin="1dp"
            android:onClick="btnBol"
            android:text="/" />
    </GridLayout>
 
</RelativeLayout>

import androidx.appcompat.app.AppCompatActivity;
 
import android.os.Bundle;
import android.view.View;
import android.widget.EditText;
import android.widget.TextView;
 
public class MainActivity extends AppCompatActivity {
 
    EditText editSayi1,editSayi2;
    TextView textSonuc;
 
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
 
        editSayi1 = findViewById(R.id.editSayi1);
        editSayi2= findViewById(R.id.editSayi2);
        textSonuc = findViewById(R.id.textResult);
    }
 
 
    public  void btnTopla(View view){
        double sayi1 = Double.parseDouble(editSayi1.getText().toString());
        double sayi2 = Double.parseDouble(editSayi2.getText().toString());
        double sonuc =  sayi1 + sayi2;
        textSonuc.setText(Double.toString(sonuc));
    }
    public  void btnCikar(View view){
        double sayi1 = Double.parseDouble(editSayi1.getText().toString());
        double sayi2 = Double.parseDouble(editSayi2.getText().toString());
        double sonuc =  sayi1 - sayi2;
        textSonuc.setText(Double.toString(sonuc));
    }
    public  void btnCarp(View view){
        double sayi1 = Double.parseDouble(editSayi1.getText().toString());
        double sayi2 = Double.parseDouble(editSayi2.getText().toString());
        double sonuc =  sayi1 * sayi2;
        textSonuc.setText(Double.toString(sonuc));
    }
    public  void btnBol(View view){
        double sayi1 = Double.parseDouble(editSayi1.getText().toString());
        double sayi2 = Double.parseDouble(editSayi2.getText().toString());
        double sonuc =  sayi1 / sayi2;
        textSonuc.setText(Double.toString(sonuc));
    }
}