Creacion interfaz grafica

Para esta actividad se realiza una app que contenga Group Box, botones, TextView, Radio Buttons y CheckBoxes.

CODIGO.

1. package com.example.app_compras_groupbox;
2.  
3. import androidx.appcompat.app.AppCompatActivity;
4.  
5. import android.os.Bundle;
6. import android.provider.MediaStore;
7. import android.view.View;
8. import android.widget.CheckBox;
9. import android.widget.RadioButton;
10. import android.widget.TextView;
11.  
12. public class MainActivity extends AppCompatActivity {
13.     TextView tvResultado;
14.     CheckBox cbImpresora, cbEscritorio, cbAuriculares;
15.     RadioButton rbAcer, rbMSI, rbLenovo;
16.     @Override
17.     protected void onCreate(Bundle savedInstanceState) {
18.         super.onCreate(savedInstanceState);
19.         setContentView(R.layout.activity_main);
20.         tvResultado = (TextView) findViewById(R.id.tvResultado);
21.         cbImpresora = (CheckBox) findViewById(R.id.cbImpresora);cbAuriculares = (CheckBox) findViewById(R.id.cbAuriculares);
22.         cbEscritorio = (CheckBox) findViewById(R.id.cbEscritorio);
23.         rbAcer = (RadioButton) findViewById(R.id.rbAcer); rbLenovo = (RadioButton) findViewById(R.id.rbLenovo); rbMSI = (RadioButton) findViewById(R.id.rbMSI);
24.     }
25.  
26.     public void Calcular(View view){
27.         int precio = 0;
28.         if (rbAcer.isChecked())
29.         {
30.             precio = 0;
31.             precio = 2200000;
32.             if (cbEscritorio.isChecked()){precio += 150000;}
33.             if (cbImpresora.isChecked()){precio += 450000;}
34.             if (cbAuriculares.isChecked()){precio += 300000;}
35.         }
36.         if (rbMSI.isChecked())
37.         {
38.             precio = 0;
39.             precio = 3500000;
40.             if (cbEscritorio.isChecked()){precio += 150000;}
41.             if (cbImpresora.isChecked()){precio += 450000;}
42.             if (cbAuriculares.isChecked()){precio += 300000;}
43.         }
44.         if (rbLenovo.isChecked())
45.         {
46.             precio = 0;
47.             precio = 1500000;
48.             if (cbEscritorio.isChecked()){precio += 150000;}
49.             if (cbImpresora.isChecked()){precio += 450000;}
50.             if (cbAuriculares.isChecked()){precio += 300000;}
51.         }
52.         String valor = String.valueOf(precio);
53.         tvResultado.setText(valor);
54.     }
55.  
56.     public void Solo1(View view)
57.     {
58.         if(rbLenovo.isChecked())
59.         {
60.             rbAcer.setChecked(false);rbMSI.setChecked(false);
61.         }
62.         if(rbAcer.isChecked())
63.         {
64.         rbLenovo.setChecked(false);rbMSI.setChecked(false);
65.         }
66.         if(rbMSI.isChecked())
67.         {
68.             rbAcer.setChecked(false);rbLenovo.setChecked(false);
69.         }
70.  
71.     }
72. }