main.java package com.cookandroid.ex4_789; import androidx.appcompat.app.AppCompatActivity; import android.os.Bundle; import android.widget.Button; import android.widget.CheckBox; import android.widget.CompoundButton; public class MainActivity extends AppCompatActivity { CheckBox chb1,chb2,chb3; Button btn1; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInsta..
