Added original source files

Added original source files from LibreTrivia

app/src/main/AndroidManifest.xml

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+<?xml version="1.0" encoding="utf-8"?>
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+    package="io.github.trytonvanmeer.libretrivia">
+
+    <uses-permission android:name="android.permission.INTERNET" />
+
+    <application
+        android:name=".LibreTriviaApplication"
+        android:allowBackup="true"
+        android:icon="@mipmap/ic_launcher"
+        android:label="@string/app_name"
+        android:roundIcon="@mipmap/ic_launcher_round"
+        android:supportsRtl="true"
+        android:theme="@style/AppTheme">
+        <activity android:name=".activities.MainActivity">
+            <intent-filter>
+                <action android:name="android.intent.action.MAIN" />
+
+                <category android:name="android.intent.category.LAUNCHER" />
+            </intent-filter>
+        </activity>
+        <activity android:name=".activities.TriviaGameActivity"
+            android:screenOrientation="fullUser"
+            android:configChanges="orientation|screenSize"/>
+        <activity android:name=".activities.TriviaGameResultsActivity"
+            android:screenOrientation="fullUser"
+            android:configChanges="orientation|screenSize"/>
+        <activity android:name=".settings.SettingsActivity"
+            android:screenOrientation="fullUser"
+            android:configChanges="orientation|screenSize"/>
+    </application>
+
+</manifest>

app/src/main/java/io/github/trytonvanmeer/libretrivia/LibreTriviaApplication.java

@@ -0,0 +1,21 @@
+package io.github.trytonvanmeer.libretrivia;
+
+import android.annotation.SuppressLint;
+import android.app.Application;
+import android.content.Context;
+
+
+public class LibreTriviaApplication extends Application {
+    @SuppressLint("StaticFieldLeak")
+    private static Context context;
+
+    @Override
+    public void onCreate() {
+        super.onCreate();
+        LibreTriviaApplication.context = getApplicationContext();
+    }
+
+    public static Context getAppContext() {
+        return LibreTriviaApplication.context;
+    }
+}

app/src/main/java/io/github/trytonvanmeer/libretrivia/activities/BaseActivity.java

@@ -0,0 +1,59 @@
+package io.github.trytonvanmeer.libretrivia.activities;
+
+import android.annotation.SuppressLint;
+import android.content.Intent;
+import android.view.Menu;
+import android.view.MenuInflater;
+import android.view.MenuItem;
+
+import com.mikepenz.aboutlibraries.Libs;
+import com.mikepenz.aboutlibraries.LibsBuilder;
+
+import androidx.appcompat.app.AppCompatActivity;
+import io.github.trytonvanmeer.libretrivia.R;
+import io.github.trytonvanmeer.libretrivia.settings.SettingsActivity;
+
+@SuppressLint("Registered")
+public class BaseActivity extends AppCompatActivity {
+
+    @Override
+    public boolean onCreateOptionsMenu(Menu menu) {
+        MenuInflater inflater = getMenuInflater();
+        inflater.inflate(R.menu.app_menu, menu);
+        return true;
+    }
+
+    @Override
+    public boolean onOptionsItemSelected(MenuItem item) {
+        switch (item.getItemId()) {
+            case R.id.settings:
+                onSettings();
+                return true;
+            case R.id.about:
+                onAbout();
+                return true;
+            case android.R.id.home:
+                onBackPressed();
+            default:
+                return super.onOptionsItemSelected(item);
+        }
+    }
+
+    private void onSettings() {
+        Intent intent = new Intent(this, SettingsActivity.class);
+        startActivity(intent);
+    }
+
+    private void onAbout() {
+        String appName = getResources().getString(R.string.app_name);
+        String appDescription = getResources().getString(R.string.app_description);
+
+        new LibsBuilder()
+                .withActivityStyle(Libs.ActivityStyle.LIGHT_DARK_TOOLBAR)
+                .withAboutIconShown(true)
+                .withAboutAppName(appName)
+                .withAboutVersionShownName(true)
+                .withAboutDescription(appDescription)
+                .start(this);
+    }
+}

app/src/main/java/io/github/trytonvanmeer/libretrivia/activities/MainActivity.java

@@ -0,0 +1,67 @@
+package io.github.trytonvanmeer.libretrivia.activities;
+
+import android.content.Intent;
+import android.os.Bundle;
+import android.widget.ArrayAdapter;
+import android.widget.Button;
+import android.widget.Spinner;
+
+import butterknife.BindView;
+import butterknife.ButterKnife;
+import io.github.trytonvanmeer.libretrivia.R;
+import io.github.trytonvanmeer.libretrivia.trivia.TriviaCategory;
+import io.github.trytonvanmeer.libretrivia.trivia.TriviaDifficulty;
+import io.github.trytonvanmeer.libretrivia.trivia.TriviaQuery;
+
+public class MainActivity extends BaseActivity {
+
+    @BindView(R.id.button_play)
+    Button buttonPlay;
+    @BindView(R.id.spinner_number)
+    Spinner spinnerNumber;
+    @BindView(R.id.spinner_category)
+    Spinner spinnerCategory;
+    @BindView(R.id.spinner_difficulty)
+    Spinner spinnerDifficulty;
+
+    @Override
+    protected void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+        setContentView(R.layout.activity_main);
+        ButterKnife.bind(this);
+
+        buttonPlay.setOnClickListener(v -> {
+            int amount = (int) spinnerNumber.getSelectedItem();
+            TriviaCategory category = (TriviaCategory) spinnerCategory.getSelectedItem();
+            TriviaDifficulty difficulty = (TriviaDifficulty) spinnerDifficulty.getSelectedItem();
+
+            TriviaQuery query = new TriviaQuery.Builder(amount)
+                    .category(category)
+                    .difficulty(difficulty)
+                    .build();
+
+            Intent intent = new Intent(getApplicationContext(), TriviaGameActivity.class);
+            intent.putExtra(TriviaGameActivity.EXTRA_TRIVIA_QUERY, query);
+            startActivity(intent);
+        });
+
+
+        Integer[] numbers = new Integer[50];
+        for (int i = 0; i < 50; ) {
+            numbers[i] = ++i;
+        }
+        spinnerNumber.setAdapter(
+                new ArrayAdapter<>(
+                        this, android.R.layout.simple_list_item_1, numbers)
+        );
+        spinnerNumber.setSelection(9);
+
+        spinnerCategory.setAdapter(
+                new ArrayAdapter<>(
+                        this, android.R.layout.simple_list_item_1, TriviaCategory.values()));
+
+        spinnerDifficulty.setAdapter(
+                new ArrayAdapter<>(
+                        this, android.R.layout.simple_list_item_1, TriviaDifficulty.values()));
+    }
+}

app/src/main/java/io/github/trytonvanmeer/libretrivia/activities/TriviaGameActivity.java

@@ -0,0 +1,227 @@
+package io.github.trytonvanmeer.libretrivia.activities;
+
+import android.app.AlertDialog;
+import android.content.Intent;
+import android.content.res.ColorStateList;
+import android.graphics.PorterDuff;
+import android.graphics.PorterDuffColorFilter;
+import android.os.AsyncTask;
+import android.os.Build;
+import android.os.Bundle;
+import android.os.Handler;
+import android.view.View;
+import android.widget.Button;
+import android.widget.LinearLayout;
+import android.widget.ProgressBar;
+import android.widget.TextView;
+
+import java.io.IOException;
+
+import androidx.fragment.app.Fragment;
+import androidx.fragment.app.FragmentTransaction;
+import butterknife.BindView;
+import butterknife.ButterKnife;
+import io.github.trytonvanmeer.libretrivia.R;
+import io.github.trytonvanmeer.libretrivia.exceptions.NoTriviaResultsException;
+import io.github.trytonvanmeer.libretrivia.fragments.TriviaGameErrorFragment;
+import io.github.trytonvanmeer.libretrivia.fragments.TriviaQuestionFragment;
+import io.github.trytonvanmeer.libretrivia.interfaces.IDownloadTriviaQuestionReceiver;
+import io.github.trytonvanmeer.libretrivia.trivia.TriviaGame;
+import io.github.trytonvanmeer.libretrivia.trivia.TriviaQuery;
+import io.github.trytonvanmeer.libretrivia.trivia.TriviaQuestion;
+import io.github.trytonvanmeer.libretrivia.util.ApiUtil;
+import io.github.trytonvanmeer.libretrivia.util.SoundUtil;
+
+public class TriviaGameActivity extends BaseActivity
+        implements IDownloadTriviaQuestionReceiver {
+    static final String EXTRA_TRIVIA_QUERY = "extra_trivia_query";
+    private final String STATE_TRIVIA_GAME = "state_trivia_game";
+
+    private TriviaGame game;
+
+    @BindView(R.id.progress_bar)
+    ProgressBar progressBar;
+    @BindView(R.id.trivia_status_bar)
+    LinearLayout triviaStatusBar;
+    @BindView(R.id.text_question_category)
+    TextView textViewQuestionCategory;
+    @BindView(R.id.text_question_difficulty)
+    TextView textViewQuestionDifficulty;
+    @BindView(R.id.text_question_progress)
+    TextView textViewQuestionProgress;
+
+    @Override
+    protected void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+        setContentView(R.layout.activity_trivia_game);
+        ButterKnife.bind(this);
+
+        if (savedInstanceState != null) {
+            this.game = (TriviaGame) savedInstanceState.getSerializable(STATE_TRIVIA_GAME);
+        } else {
+            Bundle bundle = getIntent().getExtras();
+            assert bundle != null;
+            TriviaQuery query = (TriviaQuery) bundle.get(EXTRA_TRIVIA_QUERY);
+
+            progressBar.setVisibility(View.VISIBLE);
+
+            DownloadTriviaQuestionsTask task = new DownloadTriviaQuestionsTask();
+            task.setReceiver(this);
+            task.execute(query);
+        }
+    }
+
+    @Override
+    public void onSaveInstanceState(Bundle outState) {
+        super.onSaveInstanceState(outState);
+        outState.putSerializable(STATE_TRIVIA_GAME, this.game);
+    }
+
+    @Override
+    public void onBackPressed() {
+        Fragment fragment = getSupportFragmentManager().findFragmentById(R.id.frame_trivia_game);
+
+        if (fragment instanceof TriviaGameErrorFragment) {
+            super.onBackPressed();
+        } else {
+            new AlertDialog.Builder(this)
+                    .setTitle(R.string.ui_quit_game)
+                    .setMessage(R.string.ui_quit_game_msg)
+                    .setPositiveButton(android.R.string.yes, (dialog, which) ->
+                            TriviaGameActivity.super.onBackPressed())
+                    .setNegativeButton(android.R.string.no, (dialog, which) -> {
+                    })
+                    .show();
+        }
+    }
+
+    public void onTriviaQuestionsDownloaded(String json) {
+        if (json == null) {
+            onNetworkError();
+            return;
+        } else {
+            try {
+                this.game = new TriviaGame(ApiUtil.jsonToQuestionArray(json));
+            } catch (NoTriviaResultsException e) {
+                onNoTriviaResults();
+                return;
+            }
+        }
+
+        // Setup game layout
+        progressBar.setVisibility(View.GONE);
+        triviaStatusBar.setVisibility(View.VISIBLE);
+        updateStatusBar();
+        updateTriviaQuestion();
+    }
+
+    private void updateStatusBar() {
+        String progress = getResources().getString(R.string.ui_question_progress,
+                game.getQuestionProgress(), game.getQuestionsCount());
+
+        String category = (game.getCurrentQuestion().getCategory() != null)
+                ? game.getCurrentQuestion().getCategory().toString() : "";
+
+        String difficulty = game.getCurrentQuestion().getDifficulty().toString();
+
+        textViewQuestionProgress.setText(progress);
+        textViewQuestionCategory.setText(category);
+        textViewQuestionDifficulty.setText(difficulty);
+    }
+
+    private void updateTriviaQuestion() {
+        Fragment fragment = TriviaQuestionFragment.newInstance();
+        getSupportFragmentManager().beginTransaction()
+                .replace(R.id.frame_trivia_game, fragment)
+                .setTransition(FragmentTransaction.TRANSIT_FRAGMENT_OPEN)
+                .commit();
+    }
+
+    private void onNetworkError() {
+        String msg = getResources().getString(R.string.error_network);
+        Fragment errorFragment = TriviaGameErrorFragment.newInstance(msg);
+
+        FragmentTransaction ft = getSupportFragmentManager().beginTransaction();
+        ft.replace(R.id.frame_trivia_game, errorFragment);
+        ft.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_OPEN);
+        ft.commit();
+    }
+
+    private void onNoTriviaResults() {
+        String msg = getResources().getString(R.string.error_no_trivia_results);
+        Fragment errorFragment = TriviaGameErrorFragment.newInstance(msg);
+
+        FragmentTransaction ft = getSupportFragmentManager().beginTransaction();
+        ft.replace(R.id.frame_trivia_game, errorFragment);
+        ft.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_OPEN);
+        ft.commit();
+    }
+
+    public TriviaQuestion getCurrentQuestion() {
+        return this.game.getCurrentQuestion();
+    }
+
+    public void onAnswerClick(Button answer, Button correctAnswer) {
+        boolean guess = game.nextQuestion(answer.getText().toString());
+
+        final int green = getResources().getColor(R.color.colorAccentGreen);
+        int color = guess ? green
+                : getResources().getColor(R.color.colorAccentRed);
+
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
+            ColorStateList stateList = ColorStateList.valueOf(color);
+            answer.setBackgroundTintList(stateList);
+
+            if (!guess) {
+                final ColorStateList greenStateList = ColorStateList.valueOf(green);
+                correctAnswer.setBackgroundTintList(greenStateList);
+            }
+        } else {
+            answer.getBackground().getCurrent().setColorFilter(
+                    new PorterDuffColorFilter(color, PorterDuff.Mode.MULTIPLY));
+
+            if (!guess)
+                correctAnswer.getBackground().getCurrent().setColorFilter(
+                        new PorterDuffColorFilter(green, PorterDuff.Mode.MULTIPLY));
+        }
+
+        SoundUtil.playSound(this, guess ?
+                SoundUtil.SOUND_ANSWER_CORRECT : SoundUtil.SOUND_ANSWER_WRONG);
+
+        new Handler().postDelayed(() -> {
+            if (game.isDone()) {
+                Intent intent = new Intent(getApplicationContext(), TriviaGameResultsActivity.class);
+                intent.putExtra(TriviaGameResultsActivity.EXTRA_TRIVIA_GAME, game);
+                startActivity(intent);
+                finish();
+            } else {
+                updateStatusBar();
+                updateTriviaQuestion();
+            }
+        }, 500);
+    }
+
+    private static class DownloadTriviaQuestionsTask extends AsyncTask<TriviaQuery, Integer, String> {
+        private IDownloadTriviaQuestionReceiver receiver;
+
+        @Override
+        protected String doInBackground(TriviaQuery... query) {
+            String json;
+            try {
+                json = ApiUtil.GET(query[0]);
+            } catch (IOException e) {
+                return null;
+            }
+            return json;
+        }
+
+        @Override
+        protected void onPostExecute(String json) {
+            receiver.onTriviaQuestionsDownloaded(json);
+        }
+
+        private void setReceiver(IDownloadTriviaQuestionReceiver receiver) {
+            this.receiver = receiver;
+        }
+    }
+}

app/src/main/java/io/github/trytonvanmeer/libretrivia/activities/TriviaGameResultsActivity.java

@@ -0,0 +1,47 @@
+package io.github.trytonvanmeer.libretrivia.activities;
+
+import android.os.Bundle;
+import android.widget.Button;
+import android.widget.TextView;
+
+import butterknife.BindView;
+import butterknife.ButterKnife;
+import io.github.trytonvanmeer.libretrivia.R;
+import io.github.trytonvanmeer.libretrivia.trivia.TriviaGame;
+
+public class TriviaGameResultsActivity extends BaseActivity {
+    static final String EXTRA_TRIVIA_GAME = "extra_trivia_game";
+
+    @BindView(R.id.text_results_correct)
+    TextView textResultsCorrect;
+    @BindView(R.id.text_results_wrong)
+    TextView textResultsWrong;
+    @BindView(R.id.text_results_total)
+    TextView textResultsTotal;
+    @BindView(R.id.button_return_to_menu)
+    Button buttonReturnToMenu;
+
+    @Override
+    protected void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+        setContentView(R.layout.activity_trivia_game_results);
+        ButterKnife.bind(this);
+
+        Bundle bundle = getIntent().getExtras();
+        TriviaGame game = (TriviaGame) bundle.get(EXTRA_TRIVIA_GAME);
+
+        int correctTotal = 0;
+
+        for (boolean result : game.getResults()) {
+            if (result) {
+                correctTotal++;
+            }
+        }
+
+        textResultsCorrect.setText(String.valueOf(correctTotal));
+        textResultsWrong.setText(String.valueOf(game.getQuestionsCount() - correctTotal));
+        textResultsTotal.setText(String.valueOf(game.getQuestionsCount()));
+
+        buttonReturnToMenu.setOnClickListener(v -> finish());
+    }
+}

app/src/main/java/io/github/trytonvanmeer/libretrivia/exceptions/NoTriviaResultsException.java

@@ -0,0 +1,4 @@
+package io.github.trytonvanmeer.libretrivia.exceptions;
+
+public class NoTriviaResultsException extends Exception {
+}

app/src/main/java/io/github/trytonvanmeer/libretrivia/fragments/TriviaGameErrorFragment.java

@@ -0,0 +1,46 @@
+package io.github.trytonvanmeer.libretrivia.fragments;
+
+import android.os.Bundle;
+import android.view.LayoutInflater;
+import android.view.View;
+import android.view.ViewGroup;
+import android.widget.TextView;
+
+import androidx.annotation.NonNull;
+import androidx.fragment.app.Fragment;
+import butterknife.BindView;
+import butterknife.ButterKnife;
+import io.github.trytonvanmeer.libretrivia.R;
+
+public class TriviaGameErrorFragment extends Fragment {
+    private final static String ARG_ERROR_MSG = "arg_error_msg";
+
+    @BindView(R.id.text_error_msg)
+    TextView textView;
+
+    public TriviaGameErrorFragment() {
+    }
+
+    public static TriviaGameErrorFragment newInstance(String msg) {
+        Bundle args = new Bundle();
+        args.putString(ARG_ERROR_MSG, msg);
+
+        TriviaGameErrorFragment fragment = new TriviaGameErrorFragment();
+        fragment.setArguments(args);
+        return fragment;
+    }
+
+    @Override
+    public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container,
+                             Bundle savedInstanceState) {
+        View view = inflater.inflate(R.layout.fragment_trivia_game_error, container, false);
+        ButterKnife.bind(this, view);
+
+        Bundle args;
+        if ((args = getArguments()) != null) {
+            textView.setText(args.getString(ARG_ERROR_MSG));
+        }
+
+        return view;
+    }
+}

app/src/main/java/io/github/trytonvanmeer/libretrivia/fragments/TriviaQuestionFragment.java

@@ -0,0 +1,117 @@
+package io.github.trytonvanmeer.libretrivia.fragments;
+
+import android.os.Bundle;
+import android.view.LayoutInflater;
+import android.view.View;
+import android.view.ViewGroup;
+import android.widget.Button;
+import android.widget.TextView;
+
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.List;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+import androidx.fragment.app.Fragment;
+import butterknife.BindViews;
+import butterknife.ButterKnife;
+import io.github.trytonvanmeer.libretrivia.R;
+import io.github.trytonvanmeer.libretrivia.activities.TriviaGameActivity;
+import io.github.trytonvanmeer.libretrivia.trivia.TriviaQuestion;
+import io.github.trytonvanmeer.libretrivia.trivia.TriviaQuestionMultiple;
+
+
+public class TriviaQuestionFragment extends Fragment {
+
+    private static final int buttonAnswerOneID = R.id.button_answer_one;
+    private static final int buttonAnswerTwoID = R.id.button_answer_two;
+    private static final int buttonAnswerThreeID = R.id.button_answer_three;
+    private static final int buttonAnswerFourID = R.id.button_answer_four;
+
+    @BindViews({
+            buttonAnswerOneID,
+            buttonAnswerTwoID,
+            buttonAnswerThreeID,
+            buttonAnswerFourID
+    })
+    Button[] buttonAnswers;
+
+    Button buttonAnswerCorrect;
+
+    Button buttonAnswerTrue;
+    Button buttonAnswerFalse;
+
+    public TriviaQuestionFragment() {
+    }
+
+    public static TriviaQuestionFragment newInstance() {
+        return new TriviaQuestionFragment();
+    }
+
+    @Nullable
+    @Override
+    public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container,
+                             Bundle savedInstanceState) {
+        TriviaQuestion question = ((TriviaGameActivity) getActivity()).getCurrentQuestion();
+        View view;
+
+        if (question instanceof TriviaQuestionMultiple) {
+            view = inflater.inflate(R.layout.fragment_trivia_question_multiple, container, false);
+            ButterKnife.bind(this, view);
+        } else {
+            view = inflater.inflate(R.layout.fragment_trivia_question_boolean, container, false);
+            this.buttonAnswerTrue = view.findViewById(R.id.button_answer_true);
+            this.buttonAnswerFalse = view.findViewById(R.id.button_answer_false);
+        }
+
+        TextView textViewQuestion = view.findViewById(R.id.text_trivia_question);
+        textViewQuestion.setText(question.getQuestion());
+        setupButtons();
+
+        return view;
+    }
+
+    private void setupButtons() {
+        AnswerButtonListener listener = new AnswerButtonListener();
+        TriviaQuestion question = ((TriviaGameActivity) getActivity()).getCurrentQuestion();
+
+        if (question instanceof TriviaQuestionMultiple) {
+            List<String> answers = Arrays.asList((
+                    (TriviaQuestionMultiple) question).getAnswerList());
+            Collections.shuffle(answers);
+
+            for (int i = 0; i < buttonAnswers.length; i++) {
+                buttonAnswers[i].setText(answers.get(i));
+                buttonAnswers[i].setOnClickListener(listener);
+                if (question.checkAnswer(answers.get(i))) {
+                    buttonAnswerCorrect = buttonAnswers[i];
+                }
+            }
+        } else {
+            buttonAnswerTrue.setOnClickListener(listener);
+            buttonAnswerFalse.setOnClickListener(listener);
+        }
+    }
+
+    private void disableButtons() {
+        TriviaQuestion question = ((TriviaGameActivity) getActivity()).getCurrentQuestion();
+        if (question instanceof TriviaQuestionMultiple) {
+            buttonAnswers[0].setEnabled(false);
+            buttonAnswers[1].setEnabled(false);
+            buttonAnswers[2].setEnabled(false);
+            buttonAnswers[3].setEnabled(false);
+        } else {
+            buttonAnswerTrue.setEnabled(false);
+            buttonAnswerFalse.setEnabled(false);
+        }
+    }
+
+    private class AnswerButtonListener implements View.OnClickListener {
+        @Override
+        public void onClick(View v) {
+            disableButtons();
+            ((TriviaGameActivity) getActivity()).onAnswerClick((Button) v, buttonAnswerCorrect);
+        }
+    }
+}

app/src/main/java/io/github/trytonvanmeer/libretrivia/interfaces/IDownloadTriviaQuestionReceiver.java

@@ -0,0 +1,5 @@
+package io.github.trytonvanmeer.libretrivia.interfaces;
+
+public interface IDownloadTriviaQuestionReceiver {
+    void onTriviaQuestionsDownloaded(String json);
+}

app/src/main/java/io/github/trytonvanmeer/libretrivia/settings/SettingsActivity.java

@@ -0,0 +1,37 @@
+package io.github.trytonvanmeer.libretrivia.settings;
+
+import android.os.Bundle;
+import android.view.MenuItem;
+
+import androidx.annotation.Nullable;
+import androidx.appcompat.app.ActionBar;
+import androidx.appcompat.app.AppCompatActivity;
+
+public class SettingsActivity extends AppCompatActivity {
+    @Override
+    protected void onCreate(@Nullable Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+
+        ActionBar actionBar = getSupportActionBar();
+        if (actionBar != null) {
+            actionBar.setDisplayHomeAsUpEnabled(true);
+            actionBar.setTitle(null);
+        }
+
+        getFragmentManager()
+                .beginTransaction()
+                .replace(android.R.id.content, new SettingsFragment())
+                .commit();
+    }
+
+    @Override
+    public boolean onOptionsItemSelected(MenuItem item) {
+        switch (item.getItemId()) {
+            case android.R.id.home:
+                finish();
+                return true;
+            default:
+                return super.onOptionsItemSelected(item);
+        }
+    }
+}

app/src/main/java/io/github/trytonvanmeer/libretrivia/settings/SettingsFragment.java

@@ -0,0 +1,15 @@
+package io.github.trytonvanmeer.libretrivia.settings;
+
+import android.os.Bundle;
+import android.preference.PreferenceFragment;
+
+import androidx.annotation.Nullable;
+import io.github.trytonvanmeer.libretrivia.R;
+
+public class SettingsFragment extends PreferenceFragment {
+    @Override
+    public void onCreate(@Nullable Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+        addPreferencesFromResource(R.xml.preferences);
+    }
+}

app/src/main/java/io/github/trytonvanmeer/libretrivia/trivia/TriviaCategory.java

@@ -0,0 +1,102 @@
+package io.github.trytonvanmeer.libretrivia.trivia;
+
+import java.util.HashMap;
+import java.util.Map;
+
+import io.github.trytonvanmeer.libretrivia.LibreTriviaApplication;
+import io.github.trytonvanmeer.libretrivia.R;
+
+/*
+    Categories that a Trivia Question can fall into
+ */
+public enum TriviaCategory {
+    ANY(-1, "Any", R.string.ui_any),
+
+    GENERAL_KNOWLEDGE(9, "General Knowledge",
+            R.string.category_general_knowledge),
+    ENTERTAINMENT_BOOKS(10, "Entertainment: Books",
+            R.string.category_entertainment_books),
+    ENTERTAINMENT_FILM(11, "Entertainment: Film",
+            R.string.category_entertainment_film),
+    ENTERTAINMENT_MUSIC(12, "Entertainment: Music",
+            R.string.category_entertainment_music),
+    ENTERTAINMENT_MUSICALS_THEATRES(13, "Entertainment: Musicals & Theatres",
+            R.string.category_entertainment_musicals_theatres),
+    ENTERTAINMENT_TELEVISION(14, "Entertainment: Television",
+            R.string.category_entertainment_television),
+    ENTERTAINMENT_VIDEO_GAMES(15, "Entertainment: Video Games",
+            R.string.category_entertainment_video_games),
+    ENTERTAINMENT_BOARD_GAMES(16, "Entertainment: Board Games",
+            R.string.category_entertainment_board_games),
+    ENTERTAINMENT_JAPANESE_ANIME_MANGA(31, "Entertainment: Japanese Anime & Manga",
+            R.string.category_entertainment_japanese_anime_manga),
+    ENTERTAINMENT_CARTOON_ANIMATIONS(32, "Entertainment: Cartoons & Animation",
+            R.string.category_entertainment_cartoon_animations),
+    ENTERTAINMENT_COMICS(29, "Entertainment: Comics",
+            R.string.category_entertainment_comics),
+    SCIENCE_NATURE(17, "Science & Nature",
+            R.string.category_science_nature),
+    SCIENCE_COMPUTERS(18, "Science: Computers",
+            R.string.category_science_computers),
+    SCIENCE_MATHEMATICS(19, "Science: Mathematics",
+            R.string.category_science_mathematics),
+    SCIENCE_GADGETS(30, "Science: Gadgets",
+            R.string.category_science_gadgets),
+    MYTHOLOGY(20, "Mythology",
+            R.string.category_mythology),
+    SPORTS(21, "Sports",
+            R.string.category_sports),
+    GEOGRAPHY(22, "Geography",
+            R.string.category_geography),
+    HISTORY(23, "History",
+            R.string.category_history),
+    POLITICS(24, "Politics",
+            R.string.category_politics),
+    ART(25, "Art",
+            R.string.category_art),
+    CELEBRITIES(26, "Celebrities",
+            R.string.category_celebrities),
+    ANIMALS(27, "Animals",
+            R.string.category_animals),
+    VEHICLES(28, "Vehicles",
+            R.string.category_vehicles);
+
+    // The id of the category in the opentdb api
+    // see <https://opentdb.com/api_category.php>
+    private final int ID;
+    // The name of the category in the JSON response
+    private final String name;
+    // The display name of the category
+    private final int displayName;
+
+    private static final Map<String, TriviaCategory> lookup = new HashMap<>();
+
+    static {
+        for (TriviaCategory category : TriviaCategory.values()) {
+            lookup.put(category.getName(), category);
+        }
+    }
+
+    TriviaCategory(int ID, String name, int displayName) {
+        this.ID = ID;
+        this.name = name;
+        this.displayName = displayName;
+    }
+
+    public int getID() {
+        return this.ID;
+    }
+
+    private String getName() {
+        return this.name;
+    }
+
+    public static TriviaCategory get(String name) {
+        return lookup.get(name);
+    }
+
+    @Override
+    public String toString() {
+        return LibreTriviaApplication.getAppContext().getResources().getString(this.displayName);
+    }
+}

app/src/main/java/io/github/trytonvanmeer/libretrivia/trivia/TriviaDifficulty.java

@@ -0,0 +1,46 @@
+package io.github.trytonvanmeer.libretrivia.trivia;
+
+import java.util.HashMap;
+import java.util.Map;
+
+import io.github.trytonvanmeer.libretrivia.LibreTriviaApplication;
+import io.github.trytonvanmeer.libretrivia.R;
+
+public enum TriviaDifficulty {
+    ANY("any", R.string.ui_any),
+
+    EASY("easy", R.string.difficulty_easy),
+    MEDIUM("medium", R.string.difficulty_medium),
+    HARD("hard", R.string.difficulty_hard);
+
+    // Name of difficulty used in queries
+    private final String name;
+    // Display name of the difficulty
+    private final int displayName;
+
+    private static final Map<String, TriviaDifficulty> lookup = new HashMap<>();
+
+    static {
+        for (TriviaDifficulty difficulty : TriviaDifficulty.values()) {
+            lookup.put(difficulty.getName(), difficulty);
+        }
+    }
+
+    TriviaDifficulty(String name, int displayName) {
+        this.name = name;
+        this.displayName = displayName;
+    }
+
+    public String getName() {
+        return this.name;
+    }
+
+    public static TriviaDifficulty get(String name) {
+        return lookup.get(name);
+    }
+
+    @Override
+    public String toString() {
+        return LibreTriviaApplication.getAppContext().getResources().getString(this.displayName);
+    }
+}

app/src/main/java/io/github/trytonvanmeer/libretrivia/trivia/TriviaGame.java

@@ -0,0 +1,46 @@
+package io.github.trytonvanmeer.libretrivia.trivia;
+
+import java.io.Serializable;
+import java.util.List;
+
+public class TriviaGame implements Serializable {
+    private int currentQuestion;
+    private final boolean[] results;
+    private final List<TriviaQuestion> questions;
+
+    public TriviaGame(List<TriviaQuestion> questions) {
+        this.currentQuestion = 0;
+        this.questions = questions;
+        this.results = new boolean[questions.size()];
+    }
+
+    public TriviaQuestion getCurrentQuestion() {
+        return this.questions.get(currentQuestion);
+    }
+
+    public int getQuestionProgress() {
+        return this.currentQuestion + 1;
+    }
+
+    public int getQuestionsCount() {
+        return this.questions.size();
+    }
+
+    public boolean[] getResults() {
+        return this.results;
+    }
+
+    public boolean nextQuestion(String guess) {
+        TriviaQuestion question = getCurrentQuestion();
+        boolean answer = question.checkAnswer(guess);
+
+        results[currentQuestion] = answer;
+        currentQuestion++;
+
+        return answer;
+    }
+
+    public boolean isDone() {
+        return (this.currentQuestion == questions.size());
+    }
+}

app/src/main/java/io/github/trytonvanmeer/libretrivia/trivia/TriviaQuery.java

@@ -0,0 +1,78 @@
+package io.github.trytonvanmeer.libretrivia.trivia;
+
+import java.io.Serializable;
+
+public class TriviaQuery implements Serializable {
+    private static final String BASE = "https://opentdb.com/api.php?";
+    private static final int DEFAULT_AMOUNT = 10;
+
+    private final int amount;
+    private final TriviaCategory category;
+    private final TriviaDifficulty difficulty;
+    private final TriviaType type;
+
+    private TriviaQuery(Builder builder) {
+        this.amount = builder.amount;
+        this.category = builder.category;
+        this.difficulty = builder.difficulty;
+        this.type = builder.type;
+    }
+
+    public static class Builder {
+        private final int amount;
+        private TriviaCategory category;
+        private TriviaDifficulty difficulty;
+        private TriviaType type;
+
+        public Builder() {
+            this.amount = DEFAULT_AMOUNT;
+        }
+
+        public Builder(int amount) {
+            if (amount > 50) {
+                this.amount = 50;
+            } else {
+                this.amount = amount;
+            }
+        }
+
+        public Builder category(TriviaCategory category) {
+            this.category = category;
+            return this;
+        }
+
+        public Builder difficulty(TriviaDifficulty difficulty) {
+            this.difficulty = difficulty;
+            return this;
+        }
+
+        public Builder type(TriviaType type) {
+            this.type = type;
+            return this;
+        }
+
+        public TriviaQuery build() {
+            return new TriviaQuery(this);
+        }
+    }
+
+    @Override
+    public String toString() {
+        StringBuilder url = new StringBuilder();
+
+        url.append(BASE);
+        url.append("amount=").append(this.amount);
+
+        if (this.category != null & this.category != TriviaCategory.ANY) {
+            url.append("&category=").append(this.category.getID());
+        }
+        if (this.difficulty != null & this.difficulty != TriviaDifficulty.ANY) {
+            url.append("&difficulty=").append(this.difficulty.getName());
+        }
+        if (this.type != null & this.type != TriviaType.ANY) {
+            url.append("&type=").append(this.type.getName());
+        }
+
+        return url.toString();
+    }
+}

app/src/main/java/io/github/trytonvanmeer/libretrivia/trivia/TriviaQuestion.java

@@ -0,0 +1,31 @@
+package io.github.trytonvanmeer.libretrivia.trivia;
+
+import java.io.Serializable;
+
+public abstract class TriviaQuestion implements Serializable {
+    private final TriviaCategory category;
+    private final TriviaDifficulty difficulty;
+
+    private final String question;
+
+    TriviaQuestion(TriviaCategory category, TriviaDifficulty difficulty, String question) {
+        this.category = category;
+        this.difficulty = difficulty;
+
+        this.question = question;
+    }
+
+    public TriviaCategory getCategory() {
+        return this.category;
+    }
+
+    public TriviaDifficulty getDifficulty() {
+        return this.difficulty;
+    }
+
+    public String getQuestion() {
+        return this.question;
+    }
+
+    public abstract boolean checkAnswer(String guess);
+}

app/src/main/java/io/github/trytonvanmeer/libretrivia/trivia/TriviaQuestionBoolean.java

@@ -0,0 +1,34 @@
+package io.github.trytonvanmeer.libretrivia.trivia;
+
+import android.text.Html;
+
+import com.google.gson.JsonObject;
+
+public class TriviaQuestionBoolean extends TriviaQuestion {
+
+    private final Boolean correctAnswer;
+
+    public TriviaQuestionBoolean(TriviaCategory category, TriviaDifficulty difficulty,
+                                 String question, boolean correctAnswer) {
+        super(category, difficulty, question);
+        this.correctAnswer = correctAnswer;
+    }
+
+    @Override
+    public boolean checkAnswer(String guess) {
+        return this.correctAnswer.equals(Boolean.valueOf(guess));
+    }
+
+    public boolean checkAnswer(Boolean guess) {
+        return checkAnswer(guess.toString());
+    }
+
+    public static TriviaQuestionBoolean fromJson(JsonObject json) {
+        TriviaCategory category = TriviaCategory.get(json.get("category").getAsString());
+        TriviaDifficulty difficulty = TriviaDifficulty.get(json.get("difficulty").getAsString());
+        String question = Html.fromHtml(json.get("question").getAsString()).toString();
+        Boolean correctAnswer = json.get("correct_answer").getAsBoolean();
+
+        return new TriviaQuestionBoolean(category, difficulty, question, correctAnswer);
+    }
+}

app/src/main/java/io/github/trytonvanmeer/libretrivia/trivia/TriviaQuestionMultiple.java

@@ -0,0 +1,48 @@
+package io.github.trytonvanmeer.libretrivia.trivia;
+
+import android.text.Html;
+
+import com.google.gson.JsonArray;
+import com.google.gson.JsonObject;
+
+public class TriviaQuestionMultiple extends TriviaQuestion {
+    private final String correctAnswer;
+    private final String[] incorrectAnswers;
+
+    public TriviaQuestionMultiple(TriviaCategory category, TriviaDifficulty difficulty,
+                                  String question, String correctAnswer, String[] incorrectAnswers) {
+        super(category, difficulty, question);
+
+        this.correctAnswer = correctAnswer;
+        this.incorrectAnswers = incorrectAnswers;
+    }
+
+    public String[] getAnswerList() {
+        return new String[]{correctAnswer,
+                incorrectAnswers[0],
+                incorrectAnswers[1],
+                incorrectAnswers[2]};
+    }
+
+    @Override
+    public boolean checkAnswer(String guess) {
+        return this.correctAnswer.equals(guess);
+    }
+
+    public static TriviaQuestionMultiple fromJson(JsonObject json) {
+        TriviaCategory category = TriviaCategory.get(json.get("category").getAsString());
+        TriviaDifficulty difficulty = TriviaDifficulty.get(json.get("difficulty").getAsString());
+        String question = Html.fromHtml(json.get("question").getAsString()).toString();
+        String correctAnswer = Html.fromHtml(json.get("correct_answer").getAsString()).toString();
+
+        JsonArray incorrectAnswersJson = json.get("incorrect_answers").getAsJsonArray();
+        String[] incorrectAnswers = new String[]{
+                Html.fromHtml(incorrectAnswersJson.get(0).getAsString()).toString(),
+                Html.fromHtml(incorrectAnswersJson.get(1).getAsString()).toString(),
+                Html.fromHtml(incorrectAnswersJson.get(2).getAsString()).toString()
+        };
+
+        return new TriviaQuestionMultiple(
+                category, difficulty, question, correctAnswer, incorrectAnswers);
+    }
+}

app/src/main/java/io/github/trytonvanmeer/libretrivia/trivia/TriviaType.java

@@ -0,0 +1,45 @@
+package io.github.trytonvanmeer.libretrivia.trivia;
+
+import java.util.HashMap;
+import java.util.Map;
+
+import io.github.trytonvanmeer.libretrivia.LibreTriviaApplication;
+import io.github.trytonvanmeer.libretrivia.R;
+
+public enum TriviaType {
+    ANY("any", R.string.ui_any),
+
+    MULTIPLE("multiple", R.string.question_type_multiple),
+    BOOLEAN("boolean", R.string.question_type_boolean);
+
+    // Name of type used in queries
+    private final String name;
+    // Display name of the type
+    private final int displayName;
+
+    private static final Map<String, TriviaType> lookup = new HashMap<>();
+
+    static {
+        for (TriviaType type : TriviaType.values()) {
+            lookup.put(type.getName(), type);
+        }
+    }
+
+    TriviaType(String name, int displayName) {
+        this.name = name;
+        this.displayName = displayName;
+    }
+
+    public String getName() {
+        return this.name;
+    }
+
+    public static TriviaType get(String name) {
+        return lookup.get(name);
+    }
+
+    @Override
+    public String toString() {
+        return LibreTriviaApplication.getAppContext().getResources().getString(this.displayName);
+    }
+}

app/src/main/java/io/github/trytonvanmeer/libretrivia/util/ApiUtil.java

@@ -0,0 +1,82 @@
+package io.github.trytonvanmeer.libretrivia.util;
+
+import com.google.gson.JsonArray;
+import com.google.gson.JsonElement;
+import com.google.gson.JsonObject;
+import com.google.gson.JsonParser;
+
+import java.io.BufferedInputStream;
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.InputStreamReader;
+import java.net.HttpURLConnection;
+import java.net.URL;
+import java.util.ArrayList;
+
+import io.github.trytonvanmeer.libretrivia.exceptions.NoTriviaResultsException;
+import io.github.trytonvanmeer.libretrivia.trivia.TriviaQuery;
+import io.github.trytonvanmeer.libretrivia.trivia.TriviaQuestion;
+import io.github.trytonvanmeer.libretrivia.trivia.TriviaQuestionBoolean;
+import io.github.trytonvanmeer.libretrivia.trivia.TriviaQuestionMultiple;
+import io.github.trytonvanmeer.libretrivia.trivia.TriviaType;
+
+public class ApiUtil {
+
+    private static String readStream(InputStream in) throws IOException {
+        StringBuilder builder = new StringBuilder();
+        BufferedReader reader = new BufferedReader(new InputStreamReader(in), 1000);
+
+        for (String line = reader.readLine(); line != null; line = reader.readLine()) {
+            builder.append(line);
+        }
+
+        in.close();
+        return builder.toString();
+    }
+
+    private static String GET(String query) throws IOException {
+        String response;
+
+        URL url = new URL(query);
+        HttpURLConnection connection = (HttpURLConnection) url.openConnection();
+
+        try {
+            InputStream in = new BufferedInputStream(connection.getInputStream());
+            response = readStream(in);
+        } finally {
+            connection.disconnect();
+        }
+
+        return response;
+    }
+
+    public static String GET(TriviaQuery query) throws IOException {
+        return GET(query.toString());
+    }
+
+    public static ArrayList<TriviaQuestion> jsonToQuestionArray(String json) throws NoTriviaResultsException {
+        JsonObject jsonObject = new JsonParser().parse(json).getAsJsonObject();
+
+        if (jsonObject.get("response_code").getAsInt() == 1) {
+            throw new NoTriviaResultsException();
+        }
+
+        JsonArray jsonArray = jsonObject.getAsJsonArray("results");
+
+        ArrayList<TriviaQuestion> questions = new ArrayList<>();
+
+        for (JsonElement element : jsonArray) {
+            JsonObject object = element.getAsJsonObject();
+            TriviaType type = TriviaType.get(object.get("type").getAsString());
+
+            if (type == TriviaType.MULTIPLE) {
+                questions.add(TriviaQuestionMultiple.fromJson(object));
+            } else {
+                questions.add(TriviaQuestionBoolean.fromJson(object));
+            }
+        }
+
+        return questions;
+    }
+}

app/src/main/java/io/github/trytonvanmeer/libretrivia/util/SoundUtil.java

@@ -0,0 +1,25 @@
+package io.github.trytonvanmeer.libretrivia.util;
+
+import android.content.Context;
+import android.content.SharedPreferences;
+import android.media.MediaPlayer;
+import android.preference.PreferenceManager;
+
+import io.github.trytonvanmeer.libretrivia.R;
+
+public class SoundUtil {
+    public static final int SOUND_ANSWER_CORRECT = R.raw.sound_answer_correct;
+    public static final int SOUND_ANSWER_WRONG = R.raw.sound_answer_wrong;
+
+    public static void playSound(Context context, int sound) {
+        SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(context);
+        String key_sound = context.getResources().getString(R.string.pref_sound_answer);
+        boolean pref_sound = preferences.getBoolean(key_sound, true);
+
+        if (pref_sound) {
+            final MediaPlayer player = MediaPlayer.create(context, sound);
+            player.setVolume(0.25f, 0.25f);
+            player.start();
+        }
+    }
+}

app/src/main/res/drawable-v24/ic_launcher_foreground.xml

@@ -0,0 +1,32 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:aapt="http://schemas.android.com/aapt"
+    android:width="108dp"
+    android:height="108dp"
+    android:viewportWidth="97.2"
+    android:viewportHeight="97.2">
+    <path
+        android:fillType="evenOdd"
+        android:pathData="m49.05,22.5 l-6.37,5.01 -6.36,5.01 6.36,5.01 6.37,-5.01 3.73,2.94v8.3l-10.09,7.94v14.17h9L51.69,54.64l10.09,-7.95L61.78,32.52L55.41,27.51ZM42.69,69.41v7.09h9v-7.09z"
+        android:strokeWidth="1"
+        android:strokeColor="#00000000">
+        <aapt:attr name="android:fillColor">
+            <gradient
+                android:endX=".5885"
+                android:endY="90.9159"
+                android:startX="48.7653"
+                android:startY="61.0927"
+                android:type="linear">
+                <item
+                    android:color="#44000000"
+                    android:offset="0.0" />
+                <item
+                    android:color="#00000000"
+                    android:offset="1.0" />
+            </gradient>
+        </aapt:attr>
+    </path>
+    <path
+        android:fillColor="#ffffff"
+        android:pathData="m48.6,21.6 l-6.37,5.01 -6.36,5.01 6.36,5.01 6.37,-5.01 3.73,2.94v8.3l-10.09,7.94v14.17h9V53.74l10.09,-7.95V31.62L54.96,26.61ZM42.24,68.51V75.6h9v-7.09z"
+        android:strokeWidth="1" />
+</vector>

app/src/main/res/drawable/ic_clipboard_text.xml

@@ -0,0 +1,9 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    android:width="24dp"
+    android:height="24dp"
+    android:viewportWidth="24.0"
+    android:viewportHeight="24.0">
+    <path
+        android:fillColor="#000000"
+        android:pathData="M17,9H7V7H17M17,13H7V11H17M14,17H7V15H14M12,3A1,1 0,0 1,13 4A1,1 0,0 1,12 5A1,1 0,0 1,11 4A1,1 0,0 1,12 3M19,3H14.82C14.4,1.84 13.3,1 12,1C10.7,1 9.6,1.84 9.18,3H5A2,2 0,0 0,3 5V19A2,2 0,0 0,5 21H19A2,2 0,0 0,21 19V5A2,2 0,0 0,19 3Z" />
+</vector>

app/src/main/res/drawable/ic_emoticon_sad.xml

@@ -0,0 +1,10 @@
+<?xml version="1.0" encoding="utf-8"?>
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    android:width="24dp"
+    android:height="24dp"
+    android:viewportWidth="24"
+    android:viewportHeight="24">
+    <path
+        android:fillColor="#000"
+        android:pathData="M20,12A8,8 0 0,0 12,4A8,8 0 0,0 4,12A8,8 0 0,0 12,20A8,8 0 0,0 20,12M22,12A10,10 0 0,1 12,22A10,10 0 0,1 2,12A10,10 0 0,1 12,2A10,10 0 0,1 22,12M15.5,8C16.3,8 17,8.7 17,9.5C17,10.3 16.3,11 15.5,11C14.7,11 14,10.3 14,9.5C14,8.7 14.7,8 15.5,8M10,9.5C10,10.3 9.3,11 8.5,11C7.7,11 7,10.3 7,9.5C7,8.7 7.7,8 8.5,8C9.3,8 10,8.7 10,9.5M12,14C13.75,14 15.29,14.72 16.19,15.81L14.77,17.23C14.32,16.5 13.25,16 12,16C10.75,16 9.68,16.5 9.23,17.23L7.81,15.81C8.71,14.72 10.25,14 12,14Z" />
+</vector>

app/src/main/res/layout/activity_main.xml

@@ -0,0 +1,67 @@
+<?xml version="1.0" encoding="utf-8"?>
+<androidx.constraintlayout.widget.ConstraintLayout 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:orientation="vertical"
+    tools:context="io.github.trytonvanmeer.libretrivia.activities.MainActivity">
+
+    <ScrollView
+        android:layout_width="match_parent"
+        android:layout_height="match_parent"
+        android:fillViewport="true">
+
+        <LinearLayout
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content"
+            android:layout_marginStart="8dp"
+            android:layout_marginEnd="8dp"
+            android:orientation="vertical"
+            app:layout_constraintBottom_toBottomOf="parent"
+            app:layout_constraintTop_toTopOf="parent">
+
+            <!-- Select Amount -->
+            <TextView
+                style="@style/TextLabel"
+                android:labelFor="@id/spinner_number"
+                android:text="@string/ui_amount" />
+
+            <Spinner
+                android:id="@+id/spinner_number"
+                style="@style/Spinner" />
+
+            <!-- Select Category Spinner -->
+            <TextView
+                style="@style/TextLabel"
+                android:labelFor="@id/spinner_category"
+                android:text="@string/ui_category" />
+
+            <Spinner
+                android:id="@+id/spinner_category"
+                style="@style/Spinner" />
+
+            <!-- Select Difficulty Spinner -->
+            <TextView
+                style="@style/TextLabel"
+                android:labelFor="@id/spinner_difficulty"
+                android:text="@string/ui_difficulty" />
+
+            <Spinner
+                android:id="@+id/spinner_difficulty"
+                style="@style/Spinner" />
+
+            <!-- Play Button -->
+            <Button
+                android:id="@+id/button_play"
+                style="@style/Button"
+                android:layout_width="match_parent"
+                android:layout_height="wrap_content"
+                android:layout_marginTop="16dp"
+                android:text="@string/ui_start_game"
+                android:textSize="24sp" />
+
+        </LinearLayout>
+    </ScrollView>
+
+</androidx.constraintlayout.widget.ConstraintLayout>

app/src/main/res/layout/activity_trivia_game.xml

@@ -0,0 +1,81 @@
+<?xml version="1.0" encoding="utf-8"?>
+<androidx.constraintlayout.widget.ConstraintLayout 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">
+
+    <LinearLayout
+        android:id="@+id/trivia_status_bar"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:orientation="horizontal"
+        android:visibility="invisible"
+        app:layout_constraintBottom_toTopOf="@+id/scrollView2"
+        app:layout_constraintEnd_toEndOf="parent"
+        app:layout_constraintStart_toStartOf="parent"
+        app:layout_constraintTop_toTopOf="parent"
+        tools:visibility="visible">
+
+        <LinearLayout
+            android:layout_width="0dp"
+            android:layout_height="wrap_content"
+            android:layout_gravity="center_vertical"
+            android:layout_marginStart="16dp"
+            android:layout_weight="1"
+            android:orientation="vertical">
+
+            <TextView
+                android:id="@+id/text_question_category"
+                android:layout_width="wrap_content"
+                android:layout_height="wrap_content"
+                android:textSize="16sp"
+                android:textStyle="bold"
+                tools:text="Category" />
+
+            <TextView
+                android:id="@+id/text_question_difficulty"
+                android:layout_width="wrap_content"
+                android:layout_height="wrap_content"
+                android:textSize="14sp"
+                tools:text="Difficulty" />
+
+        </LinearLayout>
+
+        <TextView
+            android:id="@+id/text_question_progress"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:layout_gravity="center"
+            android:layout_marginEnd="16dp"
+            android:textSize="32sp"
+            android:textStyle="bold"
+            tools:text="1⁄10" />
+
+    </LinearLayout>
+
+    <ScrollView
+        android:id="@+id/scrollView2"
+        android:layout_width="match_parent"
+        android:layout_height="0dp"
+        android:fillViewport="true"
+        app:layout_constraintBottom_toBottomOf="parent"
+        app:layout_constraintEnd_toEndOf="parent"
+        app:layout_constraintStart_toStartOf="parent"
+        app:layout_constraintTop_toBottomOf="@+id/trivia_status_bar">
+
+        <FrameLayout
+            android:id="@+id/frame_trivia_game"
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content" />
+    </ScrollView>
+
+    <ProgressBar
+        android:id="@+id/progress_bar"
+        android:layout_width="match_parent"
+        android:layout_height="100dp"
+        android:visibility="gone"
+        app:layout_constraintBottom_toBottomOf="parent"
+        app:layout_constraintTop_toTopOf="parent" />
+
+</androidx.constraintlayout.widget.ConstraintLayout>

app/src/main/res/layout/activity_trivia_game_results.xml

@@ -0,0 +1,94 @@
+<?xml version="1.0" encoding="utf-8"?>
+<ScrollView
+    xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:tools="http://schemas.android.com/tools"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent"
+    android:fillViewport="true">
+<LinearLayout
+    android:layout_width="match_parent"
+    android:layout_height="wrap_content"
+    android:orientation="vertical"
+    tools:context="io.github.trytonvanmeer.libretrivia.activities.TriviaGameResultsActivity">
+
+    <ImageView
+        android:layout_width="250dp"
+        android:layout_height="250dp"
+        android:layout_gravity="center"
+        android:layout_marginBottom="16dp"
+        android:scaleType="fitXY"
+        android:src="@drawable/ic_clipboard_text"
+        android:tint="@color/colorTextSecondary" />
+
+    <!-- Total Answers -->
+    <LinearLayout
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:layout_marginBottom="16dp">
+
+        <TextView
+            style="@style/ResultText"
+            android:text="@string/ui_results_total"
+            android:textColor="@color/colorAccent" />
+
+        <TextView
+            android:id="@+id/text_results_total"
+            style="@style/ResultText"
+            tools:text="10" />
+
+    </LinearLayout>
+
+    <!-- Correct Answers -->
+    <LinearLayout
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:layout_marginBottom="16dp">
+
+        <TextView
+            style="@style/ResultText"
+            android:text="@string/ui_results_correct"
+            android:textColor="@color/colorAccentGreen" />
+
+        <TextView
+            android:id="@+id/text_results_correct"
+            style="@style/ResultText"
+            tools:text="6" />
+
+    </LinearLayout>
+
+    <!-- Wrong Answers-->
+    <LinearLayout
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:layout_marginBottom="16dp">
+
+        <TextView
+            style="@style/ResultText"
+            android:text="@string/ui_results_wrong"
+            android:textColor="@color/colorAccentRed" />
+
+        <TextView
+            android:id="@+id/text_results_wrong"
+            style="@style/ResultText"
+            tools:text="4" />
+
+    </LinearLayout>
+
+    <!-- Buttons -->
+    <LinearLayout
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:gravity="center">
+
+        <Button
+            android:id="@+id/button_return_to_menu"
+            style="@style/Button"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:layout_marginTop="16dp"
+            android:text="@string/ui_return_to_menu" />
+
+    </LinearLayout>
+
+</LinearLayout>
+</ScrollView>

app/src/main/res/layout/fragment_trivia_game_error.xml

@@ -0,0 +1,34 @@
+<androidx.constraintlayout.widget.ConstraintLayout 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"
+    tools:context="io.github.trytonvanmeer.libretrivia.fragments.TriviaGameErrorFragment">
+
+    <LinearLayout
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:layout_marginTop="50dp"
+        android:orientation="vertical"
+        app:layout_constraintEnd_toEndOf="parent"
+        app:layout_constraintStart_toStartOf="parent"
+        app:layout_constraintTop_toTopOf="parent">
+
+        <ImageView
+            android:layout_width="250dp"
+            android:layout_height="250dp"
+            android:scaleType="fitXY"
+            android:src="@drawable/ic_emoticon_sad"
+            android:tint="@color/colorTextSecondary" />
+
+        <TextView
+            android:id="@+id/text_error_msg"
+            android:layout_width="match_parent"
+            android:layout_height="100dp"
+            android:layout_marginTop="50dp"
+            android:text="@string/error_no_trivia_results"
+            android:textAlignment="center" />
+
+    </LinearLayout>
+
+</androidx.constraintlayout.widget.ConstraintLayout>

app/src/main/res/layout/fragment_trivia_question_boolean.xml

@@ -0,0 +1,45 @@
+<?xml version="1.0" encoding="utf-8"?>
+<androidx.constraintlayout.widget.ConstraintLayout 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">
+
+    <LinearLayout
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:gravity="center"
+        android:orientation="vertical"
+        app:layout_constraintBottom_toBottomOf="parent"
+        app:layout_constraintStart_toStartOf="parent"
+        app:layout_constraintTop_toTopOf="parent">
+
+        <TextView
+            android:id="@+id/text_trivia_question"
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content"
+            android:layout_marginStart="8dp"
+            android:layout_marginEnd="8dp"
+            android:layout_marginBottom="16dp"
+            android:textAlignment="center"
+            android:textSize="16sp"
+            android:textStyle="bold"
+            tools:text="Is such-and-such true or false?" />
+
+        <Button
+            android:id="@+id/button_answer_true"
+            style="@style/AnswerButton"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:text="@string/ui_true" />
+
+        <Button
+            android:id="@+id/button_answer_false"
+            style="@style/AnswerButton"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:text="@string/ui_false" />
+
+    </LinearLayout>
+
+</androidx.constraintlayout.widget.ConstraintLayout>

app/src/main/res/layout/fragment_trivia_question_multiple.xml

@@ -0,0 +1,58 @@
+<?xml version="1.0" encoding="utf-8"?>
+<androidx.constraintlayout.widget.ConstraintLayout 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">
+
+    <LinearLayout
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:gravity="center"
+        android:orientation="vertical"
+        app:layout_constraintBottom_toBottomOf="parent"
+        app:layout_constraintTop_toTopOf="parent">
+
+        <TextView
+            android:id="@+id/text_trivia_question"
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content"
+            android:layout_marginStart="8dp"
+            android:layout_marginEnd="8dp"
+            android:layout_marginBottom="16dp"
+            android:textAlignment="center"
+            android:textSize="16sp"
+            android:textStyle="bold"
+            tools:text="What is the answer to this question?" />
+
+        <Button
+            android:id="@+id/button_answer_one"
+            style="@style/AnswerButton"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            tools:text="Question 1" />
+
+        <Button
+            android:id="@+id/button_answer_two"
+            style="@style/AnswerButton"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            tools:text="Question 2" />
+
+        <Button
+            android:id="@+id/button_answer_three"
+            style="@style/AnswerButton"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            tools:text="Question 3" />
+
+        <Button
+            android:id="@+id/button_answer_four"
+            style="@style/AnswerButton"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            tools:text="Question 4" />
+
+    </LinearLayout>
+
+</androidx.constraintlayout.widget.ConstraintLayout>

app/src/main/res/menu/app_menu.xml

@@ -0,0 +1,12 @@
+<?xml version="1.0" encoding="utf-8"?>
+<menu xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto">
+    <item
+        android:id="@+id/settings"
+        android:title="@string/ui_settings"
+        app:showAsAction="never" />
+    <item
+        android:id="@+id/about"
+        android:title="@string/ui_about"
+        app:showAsAction="never" />
+</menu>

app/src/main/res/mipmap-anydpi-v26/ic_launcher.xml

@@ -0,0 +1,5 @@
+<?xml version="1.0" encoding="utf-8"?>
+<adaptive-icon xmlns:android="http://schemas.android.com/apk/res/android">
+    <background android:drawable="@color/colorPrimary" />
+    <foreground android:drawable="@drawable/ic_launcher_foreground" />
+</adaptive-icon>

app/src/main/res/mipmap-anydpi-v26/ic_launcher_round.xml

@@ -0,0 +1,5 @@
+<?xml version="1.0" encoding="utf-8"?>
+<adaptive-icon xmlns:android="http://schemas.android.com/apk/res/android">
+    <background android:drawable="@color/colorPrimary" />
+    <foreground android:drawable="@drawable/ic_launcher_foreground" />
+</adaptive-icon>

app/src/main/res/values-de/strings.xml

@@ -0,0 +1,69 @@
+<resources>
+    <string name="app_description">Ein Open-Source-Trivia-Spiel</string>
+
+    <!-- Category Names -->
+    <string name="category_general_knowledge">Allgemeinwissen</string>
+    <string name="category_entertainment_books">Unterhaltung: Bücher</string>
+    <string name="category_entertainment_film">Unterhaltung: Filme</string>
+    <string name="category_entertainment_music">Unterhaltung: Musik</string>
+    <string name="category_entertainment_musicals_theatres">Unterhaltung: Musicals und Theater</string>
+    <string name="category_entertainment_television">Unterhaltung: Fernsehen</string>
+    <string name="category_entertainment_video_games">Unterhaltung: Video Spiele</string>
+    <string name="category_entertainment_board_games">Unterhaltung: Brettspiele</string>
+    <string name="category_entertainment_japanese_anime_manga">Unterhaltung: Japanische Animes &amp; Mangas</string>
+    <string name="category_entertainment_cartoon_animations">Unterhaltung: Cartoons &amp; Animation</string>
+    <string name="category_entertainment_comics">Unterhaltung: Comics</string>
+    <string name="category_science_nature">Wissenschaft und Natur</string>
+    <string name="category_science_computers">Wissenschaft: Computer</string>
+    <string name="category_science_mathematics">Wissenschaft: Mathematik</string>
+    <string name="category_science_gadgets">Wissenschaft: Gadgets</string>
+    <string name="category_mythology">Mythologie</string>
+    <string name="category_sports">Sport</string>
+    <string name="category_geography">Geographie</string>
+    <string name="category_history">Geschichte</string>
+    <string name="category_politics">Politik</string>
+    <string name="category_art">Kunst</string>
+    <string name="category_celebrities">Prominente</string>
+    <string name="category_animals">Tiere</string>
+    <string name="category_vehicles">Fahrzeuge</string>
+
+    <!-- Difficulty Names -->
+    <string name="difficulty_easy">Einfach</string>
+    <string name="difficulty_medium">Mittel</string>
+    <string name="difficulty_hard">Schwer</string>
+
+    <!-- Question Type Names -->
+    <string name="question_type_multiple">Multiple-Choice</string>
+    <string name="question_type_boolean">Richtig / Falsch</string>
+
+    <!-- UI -->
+    <string name="ui_settings">Einstellungen</string>
+    <string name="ui_about">Über</string>
+    <string name="ui_play">Spielen</string>
+    <string name="ui_start_game">Spiel starten</string>
+    <string name="ui_any">Alle</string>
+    <string name="ui_true">Richtig</string>
+    <string name="ui_false">Falsch</string>
+    <string name="ui_correct">Richtig</string>
+    <string name="ui_wrong">Falsch</string>
+    <string name="ui_amount">Fragen</string>
+    <string name="ui_category">Kategorie</string>
+    <string name="ui_difficulty">Schwierigkeit</string>
+    <string name="ui_question_progress">%1$d⁄%2$d</string>
+    <string name="ui_quit_game">Spiel verlassen</string>
+    <string name="ui_quit_game_msg">Bist du dir sicher, dass du dieses Spiel verlassen möchtest?</string>
+    <string name="ui_results_correct">Richtige Antworten</string>
+    <string name="ui_results_wrong">Flasche Antworten</string>
+    <string name="ui_results_total">Insgesamte Fragen</string>
+    <string name="ui_return_to_menu">Zurück ins Menü</string>
+
+    <!-- Error Strings -->
+    <string name="error_network"><b>Netzwerk Fehler!</b>\n
+         Verbinden mit einem Netzwerk nicht möglich</string>
+    <string name="error_no_trivia_results"><b>Keine Trivia Ergebnisse!</b>\n
+        Es wurden keine Trivia Fragen gefunden, die alle Bedingungen erfüllt haben.</string>
+    <string name="title_activity_settings">Einstellungen</string>
+
+    <!-- Setting Strings-->
+    <string name="pref_category_sound_title">Ton</string>
+</resources>

app/src/main/res/values/colors.xml

@@ -0,0 +1,12 @@
+<?xml version="1.0" encoding="utf-8"?>
+<resources>
+    <color name="colorPrimary">#F44336</color>
+    <color name="colorPrimaryDark">#D32F2F</color>
+    <color name="colorAccent">#536DFE</color>
+    <color name="colorTextPrimary">#212121</color>
+    <color name="colorTextSecondary">#757575</color>
+    <color name="colorText">#FFFFFF</color>
+
+    <color name="colorAccentRed">#D50000</color>
+    <color name="colorAccentGreen">#00C853</color>
+</resources>

app/src/main/res/values/pref_keys.xml

@@ -0,0 +1,4 @@
+<resources>
+    <string name="pref_category_sound">pref_key_category_sound</string>
+    <string name="pref_sound_answer">pref_sound_answer</string>
+</resources>

app/src/main/res/values/strings.xml

@@ -0,0 +1,69 @@
+<resources>
+    <string name="app_name" translatable="false">LibreTrivia</string>
+    <string name="app_description">An open source trivia game.</string>
+
+    <!-- Category Names -->
+    <string name="category_general_knowledge">General Knowledge</string>
+    <string name="category_entertainment_books">Entertainment: Books</string>
+    <string name="category_entertainment_film">Entertainment: Film</string>
+    <string name="category_entertainment_music">Entertainment: Music</string>
+    <string name="category_entertainment_musicals_theatres">Entertainment: Musicals &amp; Theatres</string>
+    <string name="category_entertainment_television">Entertainment: Television</string>
+    <string name="category_entertainment_video_games">Entertainment: Video Games</string>
+    <string name="category_entertainment_board_games">Entertainment: Board Games</string>
+    <string name="category_entertainment_japanese_anime_manga">Entertainment: Japanese Anime &amp; Manga</string>
+    <string name="category_entertainment_cartoon_animations">Entertainment: Cartoons &amp; Animation</string>
+    <string name="category_entertainment_comics">Entertainment: Comics</string>
+    <string name="category_science_nature">Science &amp; Nature</string>
+    <string name="category_science_computers">Science: Computers</string>
+    <string name="category_science_mathematics">Science: Mathematics</string>
+    <string name="category_science_gadgets">Science: Gadgets</string>
+    <string name="category_mythology">Mythology</string>
+    <string name="category_sports">Sports</string>
+    <string name="category_geography">Geography</string>
+    <string name="category_history">History</string>
+    <string name="category_politics">Politics</string>
+    <string name="category_art">Art</string>
+    <string name="category_celebrities">Celebrities</string>
+    <string name="category_animals">Animals</string>
+    <string name="category_vehicles">Vehicles</string>
+
+    <!-- Difficulty Names -->
+    <string name="difficulty_easy">Easy</string>
+    <string name="difficulty_medium">Medium</string>
+    <string name="difficulty_hard">Hard</string>
+
+    <!-- Question Type Names -->
+    <string name="question_type_multiple">Multiple Choice</string>
+    <string name="question_type_boolean">True / False</string>
+
+    <!-- UI -->
+    <string name="ui_settings">Settings</string>
+    <string name="ui_about">About</string>
+    <string name="ui_play">Play</string>
+    <string name="ui_start_game">Start Game</string>
+    <string name="ui_any">Any</string>
+    <string name="ui_true">True</string>
+    <string name="ui_false">False</string>
+    <string name="ui_correct">Correct</string>
+    <string name="ui_wrong">Wrong</string>
+    <string name="ui_amount">Questions</string>
+    <string name="ui_category">Category</string>
+    <string name="ui_difficulty">Difficulty</string>
+    <string name="ui_question_progress">%1$d⁄%2$d</string>
+    <string name="ui_quit_game">Quit Game</string>
+    <string name="ui_quit_game_msg">Are you sure you want to quit this game?</string>
+    <string name="ui_results_correct">Correct Answers</string>
+    <string name="ui_results_wrong">Wrong Answers</string>
+    <string name="ui_results_total">Total Questions</string>
+    <string name="ui_return_to_menu">Return To Menu</string>
+
+    <!-- Error Strings -->
+    <string name="error_network"><b>Network error!</b>\n Could not connect to a network.</string>
+    <string name="error_no_trivia_results"><b>No trivia results!</b>\n Was not able to find trivia questions that satisfied all options.</string>
+    <string name="title_activity_settings">Settings</string>
+
+    <!-- Setting Strings-->
+    <string name="pref_category_sound_title">Sound</string>
+    <string name="pref_sound_answer_title">Answer Sound Effect</string>
+</resources>

app/src/main/res/values/styles.xml

@@ -0,0 +1,42 @@
+<resources>
+
+    <!-- Base application theme. -->
+    <style name="AppTheme" parent="Theme.AppCompat.Light.DarkActionBar">
+        <!-- Customize your theme here. -->
+        <item name="colorPrimary">@color/colorPrimary</item>
+        <item name="colorPrimaryDark">@color/colorPrimaryDark</item>
+        <item name="colorAccent">@color/colorAccent</item>
+    </style>
+
+    <style name="TextLabel">
+        <item name="android:layout_width">match_parent</item>
+        <item name="android:layout_height">wrap_content</item>
+        <item name="android:textSize">18sp</item>
+    </style>
+
+    <style name="Spinner">
+        <item name="android:layout_width">match_parent</item>
+        <item name="android:layout_height">wrap_content</item>
+        <item name="android:layout_marginBottom">16dp</item>
+    </style>
+
+    <style name="Button" parent="Base.Widget.AppCompat.Button">
+        <item name="backgroundTint">@color/colorAccent</item>
+        <item name="android:textColor">@color/colorText</item>
+        <item name="android:textAlignment">center</item>
+    </style>
+
+    <style name="AnswerButton" parent="Button">
+        <item name="android:width">300dp</item>
+        <item name="android:layout_marginBottom">16dp</item>
+    </style>
+
+    <style name="ResultText">
+        <item name="android:layout_width">0dp</item>
+        <item name="android:layout_height">wrap_content</item>
+        <item name="android:layout_weight">1</item>
+        <item name="android:textAlignment">center</item>
+        <item name="android:textStyle">bold</item>
+    </style>
+
+</resources>

app/src/main/res/xml/preferences.xml

@@ -0,0 +1,15 @@
+<?xml version="1.0" encoding="utf-8"?>
+<PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android">
+
+    <PreferenceCategory
+        android:key="@string/pref_category_sound"
+        android:title="@string/pref_category_sound_title">
+
+        <CheckBoxPreference
+            android:defaultValue="true"
+            android:key="@string/pref_sound_answer"
+            android:title="@string/pref_sound_answer_title" />
+
+    </PreferenceCategory>
+
+</PreferenceScreen>