This is the .java file for my CoffeeQuiz app.

MainActivity.java

package com.example.android.coffeequizv2;

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.Button;
import android.widget.CheckBox;
import android.widget.EditText;
import android.widget.RadioButton;
import android.widget.Toast;

/**
 * This app displays a coffee quiz game and calculates the user's score.
 */

public class MainActivity extends AppCompatActivity {

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

    public void onSubmit(View view) {
        /** define the score at the beginning of the quiz game*/
        int points = 0;

        // User's name in the name field
        String userName = ((EditText) findViewById(R.id.user_name)).getText().toString();

        // Question 1 - counts 1 point for correct answer
        CheckBox q1a1 = (CheckBox) findViewById(R.id.q1a1);
        if (q1a1.isChecked()) {
            points++;
        }
        //Question 2 - counts 1 point for correct answer
        EditText text = (EditText) (findViewById(R.id.q2a1));
        String textFrom = text.getText().toString();
        String textFromField = text.getText().toString();

        if ("AMERICANO".equals(textFromField)) {
            points++;
        }
        //Question 3 - counts 1 point for correct answer

        boolean currencyChecked = ((RadioButton) findViewById(R.id.q3a1)).isChecked();
        if (currencyChecked) {
            points++;
        }

        // Question 4 - counts 1 point for correct answer
        CheckBox q4a2 = (CheckBox) findViewById(R.id.q4a2);
        if (q4a2.isChecked()) {
            points++;
        }


        //Prints out the score
        if (points < 4) {
            Toast.makeText(this, "Congratulations " + userName + "!" + "You scored: " + points + " out of 4 points.", Toast.LENGTH_LONG).show();
        } else {
            Toast.makeText(this, "Great job " + userName + "!" + "You've got all right!", Toast.LENGTH_LONG).show();
        }
    }
}