QuizActivity.javaQuizDbHelper.javaQuestion.javaQuizContract.javacolors.xmlactivity_starting_screen.xmlactivity_quiz.xmlStartingScreenActivity.java
package com.codinginflow.myawesomequiz;

import android.content.res.ColorStateList;
import android.graphics.Color;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.RadioButton;
import android.widget.RadioGroup;
import android.widget.TextView;
import android.widget.Toast;

import java.util.Collections;
import java.util.List;

public class QuizActivity extends AppCompatActivity {
    private TextView textViewQuestion;
    private TextView textViewScore;
    private TextView textViewQuestionCount;
    private TextView textViewCountDown;
    private RadioGroup rbGroup;
    private RadioButton rb1;
    private RadioButton rb2;
    private RadioButton rb3;
    private Button buttonConfirmNext;

    private ColorStateList textColorDefaultRb;

    private List<Question> questionList;
    private int questionCounter;
    private int questionCountTotal;
    private Question currentQuestion;

    private int score;
    private boolean answered;

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

        textViewQuestion = findViewById(R.id.text_view_question);
        textViewScore = findViewById(R.id.text_view_score);
        textViewQuestionCount = findViewById(R.id.text_view_question_count);
        textViewCountDown = findViewById(R.id.text_view_countdown);
        rbGroup = findViewById(R.id.radio_group);
        rb1 = findViewById(R.id.radio_button1);
        rb2 = findViewById(R.id.radio_button2);
        rb3 = findViewById(R.id.radio_button3);
        buttonConfirmNext = findViewById(R.id.button_confirm_next);

        textColorDefaultRb = rb1.getTextColors();

        QuizDbHelper dbHelper = new QuizDbHelper(this);
        questionList = dbHelper.getAllQuestions();
        questionCountTotal = questionList.size();
        Collections.shuffle(questionList);

        showNextQuestion();

        buttonConfirmNext.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (!answered) {
                    if (rb1.isChecked() || rb2.isChecked() || rb3.isChecked()) {
                        checkAnswer();
                    } else {
                        Toast.makeText(QuizActivity.this, "Please select an answer", Toast.LENGTH_SHORT).show();
                    }
                } else {
                    showNextQuestion();
                }
            }
        });
    }

    private void showNextQuestion() {
        rb1.setTextColor(textColorDefaultRb);
        rb2.setTextColor(textColorDefaultRb);
        rb3.setTextColor(textColorDefaultRb);
        rbGroup.clearCheck();

        if (questionCounter < questionCountTotal) {
            currentQuestion = questionList.get(questionCounter);

            textViewQuestion.setText(currentQuestion.getQuestion());
            rb1.setText(currentQuestion.getOption1());
            rb2.setText(currentQuestion.getOption2());
            rb3.setText(currentQuestion.getOption3());

            questionCounter++;
            textViewQuestionCount.setText("Question: " + questionCounter + "/" + questionCountTotal);
            answered = false;
            buttonConfirmNext.setText("Confirm");
        } else {
            finishQuiz();
        }
    }

    private void checkAnswer() {
        answered = true;

        RadioButton rbSelected = findViewById(rbGroup.getCheckedRadioButtonId());
        int answerNr = rbGroup.indexOfChild(rbSelected) + 1;

        if (answerNr == currentQuestion.getAnswerNr()) {
            score++;
            textViewScore.setText("Score: " + score);
        }

        showSolution();
    }

    private void showSolution() {
        rb1.setTextColor(Color.RED);
        rb2.setTextColor(Color.RED);
        rb3.setTextColor(Color.RED);

        switch (currentQuestion.getAnswerNr()) {
            case 1:
                rb1.setTextColor(Color.GREEN);
                textViewQuestion.setText("Answer 1 is correct");
                break;
            case 2:
                rb2.setTextColor(Color.GREEN);
                textViewQuestion.setText("Answer 2 is correct");
                break;
            case 3:
                rb3.setTextColor(Color.GREEN);
                textViewQuestion.setText("Answer 3 is correct");
                break;
        }

        if (questionCounter < questionCountTotal) {
            buttonConfirmNext.setText("Next");
        } else {
            buttonConfirmNext.setText("Finish");
        }
    }

    private void finishQuiz() {
        finish();
    }
}

package com.codinginflow.myawesomequiz;

import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;

import com.codinginflow.myawesomequiz.QuizContract.*;

import java.util.ArrayList;
import java.util.List;


public class QuizDbHelper extends SQLiteOpenHelper {
    private static final String DATABASE_NAME = "MyAwesomeQuiz.db";
    private static final int DATABASE_VERSION = 1;

    private SQLiteDatabase db;

    public QuizDbHelper(Context context) {
        super(context, DATABASE_NAME, null, DATABASE_VERSION);
    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        this.db = db;

        final String SQL_CREATE_QUESTIONS_TABLE = "CREATE TABLE " +
                QuestionsTable.TABLE_NAME + " ( " +
                QuestionsTable._ID + " INTEGER PRIMARY KEY AUTOINCREMENT, " +
                QuestionsTable.COLUMN_QUESTION + " TEXT, " +
                QuestionsTable.COLUMN_OPTION1 + " TEXT, " +
                QuestionsTable.COLUMN_OPTION2 + " TEXT, " +
                QuestionsTable.COLUMN_OPTION3 + " TEXT, " +
                QuestionsTable.COLUMN_ANSWER_NR + " INTEGER" +
                ")";

        db.execSQL(SQL_CREATE_QUESTIONS_TABLE);
        fillQuestionsTable();
    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        db.execSQL("DROP TABLE IF EXISTS " + QuestionsTable.TABLE_NAME);
        onCreate(db);
    }

    private void fillQuestionsTable() {
        Question q1 = new Question("A is correct", "A", "B", "C", 1);
        addQuestion(q1);
        Question q2 = new Question("B is correct", "A", "B", "C", 2);
        addQuestion(q2);
        Question q3 = new Question("C is correct", "A", "B", "C", 3);
        addQuestion(q3);
        Question q4 = new Question("A is correct again", "A", "B", "C", 1);
        addQuestion(q4);
        Question q5 = new Question("B is correct again", "A", "B", "C", 2);
        addQuestion(q5);
    }

    private void addQuestion(Question question) {
        ContentValues cv = new ContentValues();
        cv.put(QuestionsTable.COLUMN_QUESTION, question.getQuestion());
        cv.put(QuestionsTable.COLUMN_OPTION1, question.getOption1());
        cv.put(QuestionsTable.COLUMN_OPTION2, question.getOption2());
        cv.put(QuestionsTable.COLUMN_OPTION3, question.getOption3());
        cv.put(QuestionsTable.COLUMN_ANSWER_NR, question.getAnswerNr());
        db.insert(QuestionsTable.TABLE_NAME, null, cv);
    }

    public List<Question> getAllQuestions() {
        List<Question> questionList = new ArrayList<>();
        db = getReadableDatabase();
        Cursor c = db.rawQuery("SELECT * FROM " + QuestionsTable.TABLE_NAME, null);

        if (c.moveToFirst()) {
            do {
                Question question = new Question();
                question.setQuestion(c.getString(c.getColumnIndex(QuestionsTable.COLUMN_QUESTION)));
                question.setOption1(c.getString(c.getColumnIndex(QuestionsTable.COLUMN_OPTION1)));
                question.setOption2(c.getString(c.getColumnIndex(QuestionsTable.COLUMN_OPTION2)));
                question.setOption3(c.getString(c.getColumnIndex(QuestionsTable.COLUMN_OPTION3)));
                question.setAnswerNr(c.getInt(c.getColumnIndex(QuestionsTable.COLUMN_ANSWER_NR)));
                questionList.add(question);
            } while (c.moveToNext());
        }

        c.close();
        return questionList;
    }
}

package com.codinginflow.myawesomequiz;

public class Question {
    private String question;
    private String option1;
    private String option2;
    private String option3;
    private int answerNr;

    public Question() {
    }

    public Question(String question, String option1, String option2, String option3, int answerNr) {
        this.question = question;
        this.option1 = option1;
        this.option2 = option2;
        this.option3 = option3;
        this.answerNr = answerNr;
    }

    public String getQuestion() {
        return question;
    }

    public void setQuestion(String question) {
        this.question = question;
    }

    public String getOption1() {
        return option1;
    }

    public void setOption1(String option1) {
        this.option1 = option1;
    }

    public String getOption2() {
        return option2;
    }

    public void setOption2(String option2) {
        this.option2 = option2;
    }

    public String getOption3() {
        return option3;
    }

    public void setOption3(String option3) {
        this.option3 = option3;
    }

    public int getAnswerNr() {
        return answerNr;
    }

    public void setAnswerNr(int answerNr) {
        this.answerNr = answerNr;
    }
}

package com.codinginflow.myawesomequiz;

import android.provider.BaseColumns;

public final class QuizContract {

    private QuizContract() {
    }

    public static class QuestionsTable implements BaseColumns {
        public static final String TABLE_NAME = "quiz_questions";
        public static final String COLUMN_QUESTION = "question";
        public static final String COLUMN_OPTION1 = "option1";
        public static final String COLUMN_OPTION2 = "option2";
        public static final String COLUMN_OPTION3 = "option3";
        public static final String COLUMN_ANSWER_NR = "answer_nr";
    }
}

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <color name="colorPrimary">#795548</color>
    <color name="colorPrimaryDark">#5D4037</color>
    <color name="colorAccent">#FFEB3B</color>

    <color name="colorBackground">#BCAAA4</color>
</resources>

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 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="match_parent"
    android:layout_height="match_parent"
    android:background="@color/colorBackground"
    android:padding="16dp"
    tools:context="com.codinginflow.myawesomequiz.StartingScreenActivity">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerHorizontal="true"
        android:layout_marginTop="30dp"
        android:text="My Awesome Quiz"
        android:textColor="@android:color/black"
        android:textSize="35sp" />

    <TextView
        android:id="@+id/text_view_highscore"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_above="@id/button_start_quiz"
        android:layout_centerHorizontal="true"
        android:layout_marginBottom="32dp"
        android:text="Highscore: 0"
        android:textSize="20sp" />

    <Button
        android:id="@+id/button_start_quiz"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerInParent="true"
        android:text="Start Quiz" />

</RelativeLayout>

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 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="match_parent"
    android:layout_height="match_parent"
    android:background="@color/colorBackground"
    android:padding="16dp"
    tools:context="com.codinginflow.myawesomequiz.QuizActivity">

    <TextView
        android:id="@+id/text_view_score"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Score: 0"
        android:textColor="@android:color/black" />

    <TextView
        android:id="@+id/text_view_question_count"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@id/text_view_score"
        android:text="Question: 1/x"
        android:textColor="@android:color/black" />

    <TextView
        android:id="@+id/text_view_countdown"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentEnd="true"
        android:text="00:30"
        android:textColor="@android:color/black"
        android:textSize="40sp" />

    <TextView
        android:id="@+id/text_view_question"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_above="@id/radio_group"
        android:layout_marginBottom="16dp"
        android:text="Here will be the question text\nHere will be the question text\nHere will be the question text"
        android:textAlignment="center"
        android:textColor="@android:color/black"
        android:textSize="20sp" />

    <RadioGroup
        android:id="@+id/radio_group"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerVertical="true">

        <RadioButton
            android:id="@+id/radio_button1"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Option 1" />

        <RadioButton
            android:id="@+id/radio_button2"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Option 2" />

        <RadioButton
            android:id="@+id/radio_button3"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Option 3" />

    </RadioGroup>

    <Button
        android:id="@+id/button_confirm_next"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_below="@id/radio_group"
        android:layout_marginTop="16dp"
        android:text="Confirm" />

</RelativeLayout>

package com.codinginflow.myawesomequiz;

import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;

public class StartingScreenActivity extends AppCompatActivity {

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

        Button buttonStartQuiz = findViewById(R.id.button_start_quiz);
        buttonStartQuiz.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                startQuiz();
            }
        });
    }

    private void startQuiz() {
        Intent intent = new Intent(StartingScreenActivity.this, QuizActivity.class);
        startActivity(intent);
    }
}