activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<ScrollView
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content">
<LinearLayout
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.example.android.quizapp.MainActivity"
    android:orientation="vertical"
    android:padding="20dp">
    <LinearLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="vertical"
        android:paddingBottom="10dp">
        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Check the true statements:"/>
            <CheckBox
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="This app is for an iOS device"
                android:id="@+id/checkboxTrueFalseQuestion1"/>
            <CheckBox
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="This project is for beginners"
                android:id="@+id/checkboxTrueFalseQuestion2"/>
            <CheckBox
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="<- This is a checkbox"
                android:id="@+id/checkboxTrueFalseQuestion3"/>
    </LinearLayout>
    <LinearLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="vertical"
        android:paddingBottom="10dp">
        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="What is the first name of the president of the United States of America?"/>
        <EditText
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/text_question_name_president"
            android:hint="Insert name here"/>
    </LinearLayout>
    <LinearLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="vertical"
        android:paddingBottom="10dp">
        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="What is the name of this course?"/>
        <RadioGroup
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/radiogroup_name_course">
            <RadioButton
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:id="@+id/radioButton1_name_course"
                android:text="iOS for Beginners"/>
            <RadioButton
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:id="@+id/radioButton2_name_course"
                android:text="Android Development for Beginners"/>
            <RadioButton
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:id="@+id/radioButton3_name_course"
                android:text="Android Development for Experts"/>
        </RadioGroup>
    </LinearLayout>
    <LinearLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="vertical"
        android:paddingBottom="10dp">
        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="What website is this course from?"/>
        <RadioGroup
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/radioGroup_website_course">
            <RadioButton
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:id="@+id/radioButton1_website_course"
                android:text="https://www.udacity.com"/>
            <RadioButton
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:id="@+id/radioButton2_website_course"
                android:text="https://www.google.com"/>
            <RadioButton
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:id="@+id/radioButton3_website_course"
                android:text="https://androidfor.beginners.com"/>
        </RadioGroup>
    </LinearLayout>
    <LinearLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="vertical"
        android:paddingBottom="10dp">
        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="How many lessons has this course?"/>
        <RadioGroup
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/radioGroup_number_lessons"
            android:orientation="horizontal">
            <RadioButton
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:id="@+id/radioButton1_number_lessons"
                android:text="1"/>
            <RadioButton
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:id="@+id/radioButton2_number_lessons"
                android:text="2"/>
            <RadioButton
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:id="@+id/radioButton3_number_lessons"
                android:text="3"/>
            <RadioButton
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:id="@+id/radioButton4_number_lessons"
                android:text="4"/>
        </RadioGroup>
    </LinearLayout>

    <Button
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:onClick="verify"
        android:text="verify answers"/>
    </LinearLayout>
</ScrollView>

MainActivity.java

package com.example.android.quizapp;

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

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }
    public void verify(View v) {
        int correctAnswers = 0;
        CheckBox check1 = (CheckBox) findViewById(R.id.checkboxTrueFalseQuestion1);
        CheckBox check2 = (CheckBox) findViewById(R.id.checkboxTrueFalseQuestion2);
        CheckBox check3 = (CheckBox) findViewById(R.id.checkboxTrueFalseQuestion3);
        if (!check1.isChecked()) {
            correctAnswers+=1;
        }
        if (check2.isChecked()) {
            correctAnswers+=1;
        }
        if (check3.isChecked()) {
            correctAnswers+=1;
        }
        EditText editText = (EditText) findViewById(R.id.text_question_name_president);
        if (editText.getText().toString().equalsIgnoreCase("donald")) {
            correctAnswers+=1;
        }
        RadioGroup radioGroup = (RadioGroup) findViewById(R.id.radiogroup_name_course);
        if (radioGroup.getCheckedRadioButtonId() == R.id.radioButton2_name_course) {
            correctAnswers+=1;
        }
        RadioGroup radioGroup2 = (RadioGroup) findViewById(R.id.radioGroup_website_course);
        if (radioGroup2.getCheckedRadioButtonId() == R.id.radioButton1_website_course) {
            correctAnswers+=1;
        }
        RadioGroup radioGroup3 = (RadioGroup) findViewById(R.id.radioGroup_number_lessons);
        if (radioGroup3.getCheckedRadioButtonId() == R.id.radioButton3_number_lessons) {
            correctAnswers+=1;
        }
        Toast.makeText(getApplicationContext(),"Result: "+String.valueOf(correctAnswers)+" correct answers out of 7.",Toast.LENGTH_LONG).show();
    }
}