Just Java

public class MainActivity extends AppCompatActivity {

    int quantity = 3; // 3den başlıyor kişi sayısı


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



    }



public void submitOrder(View view){//Submit tuşuna basıldığında

        CheckBox whippedCreamCheckBox = (CheckBox)findViewById(R.id.whipped_cream_checkbox);//ChechBox ın ıd sini belirtiyoruz
        boolean hasWhippedCream = whippedCreamCheckBox.isChecked();// İşaretlenmişsse true, işaretlenmemişse false


        EditText name = (EditText)findViewById(R.id.name_field);//Edittext Id
        String isim = name.getText().toString();//Yazıyı al Stringe dönüştür

        CheckBox chocalateBox = (CheckBox)findViewById(R.id.chocolate_checkbox);
        boolean hasChocalateBox = chocalateBox.isChecked();

        int price = calculatePrice(hasWhippedCream,hasChocalateBox);

        String priceMessage = createOrderSummary(price,hasWhippedCream,hasChocalateBox,isim);
        displayMessage(priceMessage);

    }



private int calculatePrice(boolean addWhippedCream,boolean addChocalate){
        int baseprice = 5;
        if (addWhippedCream){ 
            baseprice = baseprice + 1;
        }
        if (addChocalate){//                                       
            baseprice = baseprice + 2; 
        }
        return quantity * baseprice;
    }
    
    private String createOrderSummary(int price,boolean addWhippedCream,boolean chocalateBox,String name){
        String priceMessage = "Name : " + name ; //Name ve edittextte girilen ismi alcak göstercek :D
        priceMessage += "\n Add whipped Cream? " + addWhippedCream;//CheckBox
        priceMessage += "\n Add chocalate? " + chocalateBox;//CheckBox
        priceMessage += "\n Quantity: " + quantity; //+= şu anlamda priceMessage = priceMessage + "Quantity :" + quantity;
        priceMessage += "\n Total Tl : " + price;
        priceMessage += "\n Thank  You! ";
        return priceMessage;
    }