GUI Quiz Application using Tkinter and Open Trivia DB

#programming #python #tkinter #gui

In this blog, we'll learn to build a Graphical User Interface (GUI) Quiz Application using the Tkinter Python built-in module. The task is to ask multiple-choice questions, collect user answers and finally display the results. Before coding the GUI, we'll first see how to fetch multiple-choice questions, their correct answers, and the choices from the Open Trivia DB API. The Open Trivia Database provides a completely free JSON API for use in programming projects. Use of this API does not require an API Key. To make the task more interesting, we'll also randomize the order of choices.

Watch the demo video to see what we are building:

The following modules and concepts will be utilized in this project:

We'll be segregating our different functionalities into different classes and files.

Fetching Questions

As we discussed above, we'll be using the Open Trivia DB API to get the questions. Head over to their API, select the number of questions, category, and difficulty. The question type should be Multiple Choice and the encoding should be Default Encoding. Click on Generate API URL and you'll get an API URL.

Sample API URL: https://opentdb.com/api.php?amount=10&type=multiple

For fetching the questions, we'll be using requests module. It can be installed as:

$ pip install requests

Let's create a Python file quiz_data.py to fetch the quiz questions and answers using the API URL generated above.

import requests

parameters = {
    "amount": 10,
    "type": "multiple"
}

response = requests.get(url="https://opentdb.com/api.php", params=parameters)
question_data = response.json()["results"]

In the above script, instead of directly adding the amount and type parameters in the URL, we have created a parameters dictionary and added the respective values. After that, we're making a GET request using requests library on the Open Trivia DB API URL. A sample JSON response looks like this:

{
  "response_code": 0,
  "results": [
    {
      "category": "Entertainment: Video Games",
      "type": "multiple",
      "difficulty": "hard",
      "question": "What was the name of the hero in the 80s animated video game &#039;Dragon&#039;s Lair&#039;?",
      "correct_answer": "Dirk the Daring",
      "incorrect_answers": ["Arthur", "Sir Toby Belch", "Guy of Gisbourne"]
    },
    {
      "category": "Entertainment: Video Games",
      "type": "multiple",
      "difficulty": "medium",
      "question": "Which of these game franchises were made by Namco?",
      "correct_answer": "Tekken",
      "incorrect_answers": ["Street Fighter", "Mortal Kombat", "Dragon Quest"]
    }
  ]
}

The JSON data contains a dictionary with two keys - response_code and results. The response_code tells developers what the API is doing. The results is a list we are interested in. So, we have stored the value of results in a variable question_data.

Question Model

Question model is nothing but a Python class with three attributes - question_text, correct_answer and choices. question_text is the question, correct_answer is the correct answer for that question and choices is a list of options for that question.

Let's create a question_model.py file and create the class in it:

class Question:
    def __init__ (self, question: str, correct_answer: str, choices: list):
        self.question_text = question
        self.correct_answer = correct_answer
        self.choices = choices

Quiz Brain

The QuizBrain, as the name suggests, is the brain of the application. Let's create quiz_brain.py file and add the following code there:

class QuizBrain:

    def __init__ (self, questions):
        self.question_no = 0
        self.score = 0
        self.questions = questions
        self.current_question = None

    def has_more_questions(self):
        """To check if the quiz has more questions"""

        return self.question_no < len(self.questions)

    def next_question(self):
        """Get the next question by incrementing the question number"""

        self.current_question = self.questions[self.question_no]
        self.question_no += 1
        q_text = self.current_question.question_text
        return f"Q.{self.question_no}: {q_text}"

    def check_answer(self, user_answer):
        """Check the user answer against the correct answer and maintain the score"""

        correct_answer = self.current_question.correct_answer
        if user_answer.lower() == correct_answer.lower():
            self.score += 1
            return True
        else:
            return False

    def get_score(self):
        """Get the number of correct answers, wrong answers and score percentage."""

        wrong = self.question_no - self.score
        score_percent = int(self.score / self.question_no * 100)
        return (self.score, wrong, score_percent)

The QuizBrain class takes questions, list of questions. Additionally, the question_no and score attributes are initialized with 0 and the current_question is set to None initially.

The first method has_more_questions() checks whether the quiz has more questions or not. The next method next_question() gets the question from the questions list at index question_no and then increments the question_no attribute returns a formatted question. The check_answer() method takes user_answer as an argument and checks whether the user's answer is correct or not. It also maintains the score and returns boolean values. The last method get_score() returns the number of correct answers, wrong answers, and score percentage.

Quiz UI

Let's move to the next part where we create the user interface of the application. Create a quiz_ui.py file and add the following content:

from tkinter import Tk, Canvas, StringVar, Label, Radiobutton, Button, messagebox
from quiz_brain import QuizBrain

THEME_COLOR = "#375362"

class QuizInterface:

    def __init__ (self, quiz_brain: QuizBrain) -> None:
        self.quiz = quiz_brain
        self.window = Tk()
        self.window.title("iQuiz App")
        self.window.geometry("850x530")

        # Display Title
        self.display_title()

        # Creating a canvas for question text, and dsiplay question
        self.canvas = Canvas(width=800, height=250)
        self.question_text = self.canvas.create_text(400, 125,
                                                     text="Question here",
                                                     width=680,
                                                     fill=THEME_COLOR,
                                                     font=(
                                                         'Ariel', 15, 'italic')
                                                     )
        self.canvas.grid(row=2, column=0, columnspan=2, pady=50)
        self.display_question()

        # Declare a StringVar to store user's answer
        self.user_answer = StringVar()

        # Display four options(radio buttons)
        self.opts = self.radio_buttons()
        self.display_options()

        # To show whether the answer is correct or wrong
        self.feedback = Label(self.window, pady=10, font=("ariel", 15, "bold"))
        self.feedback.place(x=300, y=380)

        # Next and Quit Button
        self.buttons()

        # Mainloop
        self.window.mainloop()

    def display_title(self):
        """To display title"""

        # Title
        title = Label(self.window, text="iQuiz Application",
                      width=50, bg="green", fg="white", font=("ariel", 20, "bold"))

        # place of the title
        title.place(x=0, y=2)

    def display_question(self):
        """To display the question"""

        q_text = self.quiz.next_question()
        self.canvas.itemconfig(self.question_text, text=q_text)

    def radio_buttons(self):
        """To create four options (radio buttons)"""

        # initialize the list with an empty list of options
        choice_list = []

        # position of the first option
        y_pos = 220

        # adding the options to the list
        while len(choice_list) < 4:

            # setting the radio button properties
            radio_btn = Radiobutton(self.window, text="", variable=self.user_answer,
                                    value='', font=("ariel", 14))

            # adding the button to the list
            choice_list.append(radio_btn)

            # placing the button
            radio_btn.place(x=200, y=y_pos)

            # incrementing the y-axis position by 40
            y_pos += 40

        # return the radio buttons
        return choice_list

    def display_options(self):
        """To display four options"""

        val = 0

        # deselecting the options
        self.user_answer.set(None)

        # looping over the options to be displayed for the
        # text of the radio buttons.
        for option in self.quiz.current_question.choices:
            self.opts[val]['text'] = option
            self.opts[val]['value'] = option
            val += 1

    def next_btn(self):
        """To show feedback for each answer and keep checking for more questions"""

        # Check if the answer is correct
        if self.quiz.check_answer(self.user_answer.get()):
            self.feedback["fg"] = "green"
            self.feedback["text"] = 'Correct answer! \U0001F44D'
        else:
            self.feedback['fg'] = 'red'
            self.feedback['text'] = ('\u274E Oops! \n'
                                     f'The right answer is: {self.quiz.current_question.correct_answer}')

        if self.quiz.has_more_questions():
            # Moves to next to display next question and its options
            self.display_question()
            self.display_options()
        else:
            # if no more questions, then it displays the score
            self.display_result()

            # destroys the self.window
            self.window.destroy()

    def buttons(self):
        """To show next button and quit button"""

        # The first button is the Next button to move to the
        # next Question
        next_button = Button(self.window, text="Next", command=self.next_btn,
                             width=10, bg="green", fg="white", font=("ariel", 16, "bold"))

        # palcing the button on the screen
        next_button.place(x=350, y=460)

        # This is the second button which is used to Quit the self.window
        quit_button = Button(self.window, text="Quit", command=self.window.destroy,
                             width=5, bg="red", fg="white", font=("ariel", 16, " bold"))

        # placing the Quit button on the screen
        quit_button.place(x=700, y=50)

    def display_result(self):
        """To display the result using messagebox"""
        correct, wrong, score_percent = self.quiz.get_score()

        correct = f"Correct: {correct}"
        wrong = f"Wrong: {wrong}"

        # calculates the percentage of correct answers
        result = f"Score: {score_percent}%"

        # Shows a message box to display the result
        messagebox.showinfo("Result", f"{result}\n{correct}\n{wrong}")

Well, a very large script but if you look at it carefully, it's quite easy to understand. The code is well documented.

Getting Things Together

Since all the components are ready to be integrated together, let's create a main.py file and add the following content there:

from question_model import Question
from quiz_data import question_data
from quiz_brain import QuizBrain
from quiz_ui import QuizInterface
from random import shuffle
import html

question_bank = []
for question in question_data:
    choices = []
    question_text = html.unescape(question["question"])
    correct_answer = html.unescape(question["correct_answer"])
    incorrect_answers = question["incorrect_answers"]
    for ans in incorrect_answers:
        choices.append(html.unescape(ans))
    choices.append(correct_answer)
    shuffle(choices)
    new_question = Question(question_text, correct_answer, choices)
    question_bank.append(new_question)

quiz = QuizBrain(question_bank)

quiz_ui = QuizInterface(quiz)

print("You've completed the quiz")
print(f"Your final score was: {quiz.score}/{quiz.question_no}")

Let's import all the classes from the different files we have created. In addition to that, we also need shuffle method from the random module and the html module. We have a list question_bank. We are iterating over the question_data that we receive from quiz_data.py file. If you see the sample response, you will find some text such as 'Dragon&#039. They need to be unescaped using the html.unescape method. We have a choices list that will contain the correct answer as well as the incorrect answers. The list will be shuffled using the shuffle method from the random module. After shuffling, we are creating question using the Question model from quiz_model.py file and appending it the question_bank list.

Next, we're creating an object quiz of QuizBrain class which requires a list of questions. So, we're passing question_bank to it. After that, we're creating an object quiz_ui of QuizInterface class which requires an object of QuizBrain class, so we have passed the newly created quiz object to it.

Now that everything is ready, we are ready to run the application.