Android Checkbox demo

gistfile1.txt

package com.example.mycalculator;

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.widget.Button;
import android.widget.CheckBox;
import android.widget.CompoundButton;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {

    Button button;
    CheckBox math, phy;


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

        math = this.findViewById(R.id.math);

        math.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
                                            @Override
                                            public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
                                                String message = "";
                                                if (isChecked) {
                                                    message = "You selected ";
                                                } else {
                                                    message = "You did not select";
                                                }

                                                Toast.makeText(getApplicationContext(), message, Toast.LENGTH_SHORT).show();
                                            }
                                        }
        );

    }
}