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multichoice.module in Quiz 5

Same filename and directory in other branches
  1. 5.2 multichoice.module
  2. 6.2 multichoice.module

Multiple choice question type for quiz module

Allows the creation of multiple choice questions (ex: a, b, c, d or true/false)

File

multichoice.module
View source 
<?php

define('MULTICHOICE_NAME', 'Multi-Choice Question');

/**
 * @file
 * Multiple choice question type for quiz module
 *
 * Allows the creation of multiple choice questions (ex: a, b, c, d or true/false)
 */

/**
 * Implementation of hook_perm().
 */
function multichoice_perm() {
  return array(
    'create multichoice',
    'edit own multichoice',
  );
}

/**
 * Implementation of hook_access().
 */
function multichoice_access($op, $node) {
  global $user;
  if ($op == 'create') {
    return user_access('create multichoice');
  }
  if ($op == 'update' || $op == 'delete') {
    if (user_access('edit own multichoice') && $user->uid == $node->uid) {
      return TRUE;
    }
  }
}

/**
 * Implementation of hook_node_info().
 */
function multichoice_node_info() {
  return array(
    'multichoice' => array(
      'name' => t(MULTICHOICE_NAME),
      'module' => 'multichoice',
      'description' => t('A question type for the quiz module: allows you to create multiple choice questions (ex: A, B, C, D or true/false)'),
    ),
  );
}

/**
 * Implementation of hook_menu().
 */
function multichoice_menu($may_cache) {
  $items = array();
  if ($may_cache) {
    $items[] = array(
      'path' => 'node/add/multichoice',
      'title' => t(MULTICHOICE_NAME),
      'access' => user_access('create multichoice'),
    );
  }
  return $items;
}

/**
 * Implementation of hook_form().
 */
function multichoice_form(&$node) {

  // quiz id here to tie creating a question to a specific quiz
  $quiz_id = arg(3);
  if (!empty($quiz_id)) {
    $form['quiz_id'] = array(
      '#type' => 'value',
      '#value' => $quiz_id,
    );
  }

  // Display multichoice form
  $form['title'] = array(
    '#type' => 'textfield',
    '#title' => t('Title'),
    '#default_value' => $node->title,
    '#required' => TRUE,
    '#description' => t('Add a title that will help distinguish this question from other questions. This will not be seen during the quiz.'),
  );
  $form['body'] = array(
    '#type' => 'textarea',
    '#title' => t('Question'),
    '#default_value' => $node->body,
    '#required' => TRUE,
  );
  $form['body_filter']['format'] = filter_form($node->format);
  $form['multiple_answers'] = array(
    '#type' => 'checkbox',
    '#title' => t('Multiple answers'),
    '#default_value' => $node->multiple_answers,
  );

  // Determine number of answer rows to display
  if (!isset($node->rows)) {
    $node->rows = max(2, $node->answers ? count($node->answers) : 5);
  }
  if ($_POST['more']) {
    $node->rows += 5;
  }
  $answers = $node->answers;

  // Display answer rows
  $form['answers'] = array(
    '#type' => 'fieldset',
    '#title' => t('Choices'),
    '#tree' => TRUE,
    '#theme' => 'multichoice_form',
  );
  for ($i = 0; $i < $node->rows; $i++) {
    $form['answers'][$i]['correct'] = array(
      '#type' => 'checkbox',
      '#default_value' => $answers[$i]['points'],
    );
    $form['answers'][$i]['answer'] = array(
      '#type' => 'textarea',
      '#default_value' => $answers[$i]['answer'],
      '#cols' => 30,
      '#rows' => 2,
    );
    $form['answers'][$i]['feedback'] = array(
      '#type' => 'textarea',
      '#default_value' => $answers[$i]['feedback'],
      '#cols' => 30,
      '#rows' => 2,
    );
    if ($answers[$i]['aid']) {
      $form['answers'][$i]['delete'] = array(
        '#type' => 'checkbox',
        '#default_value' => 0,
      );
      $form['answers'][$i]['aid'] = array(
        '#type' => 'hidden',
        '#value' => $answers[$i]['aid'],
      );
    }
  }
  $form['more'] = array(
    '#type' => 'checkbox',
    '#title' => t('I need more answers'),
  );

  // if coming from quiz view, go back there on submit
  if (!empty($quiz_id)) {
    $form['#redirect'] = 'node/' . $quiz_id . '/questions';
  }
  return $form;
}

/**
 * Implementation of hook_validate().
 */
function multichoice_validate(&$node) {

  // Hard-code questions to have no teaser and to not be promoted to front page
  $node->teaser = 0;
  $node->promote = 0;
  if (!$node->nid && empty($_POST)) {
    return;
  }

  // Validate body
  if (!$node->body) {
    form_set_error('body', t('Question text is empty'));
  }

  // Validate answers
  $answers = 0;
  $corrects = 0;
  while (list($key, $answer) = each($node->answers)) {
    if (trim($answer['answer']) != '') {
      $answers++;
      if ($answer['correct'] > 0) {
        if ($corrects && !$node->multiple_answers) {
          form_set_error('multiple_answers', t('Single choice yet multiple correct answers are present'));
        }
        $corrects++;
      }
    }
    else {

      // warn feedback is present without an answer
      if (trim($answer['feedback']) != '') {
        form_set_error("answers][{$key}][feedback", t('Feedback is given without an answer.'));
      }

      // warn marking correct without answer
      if ($answer['correct'] > 0) {
        form_set_error("answers][{$key}][correct", t('Empty answer marked as correct choice.'));
      }
    }
  }
  if (!$corrects) {
    form_set_error("answers][0]['correct'", t('No correct choice(s).'));
  }
  if ($node->multiple_answers && $corrects < 2) {
    form_set_error('multiple_answers', t('Multiple answers selected, but only %count correct answer(s) present.', array(
      '%count' => $corrects,
    )));
  }
  if (!$answers) {
    form_set_error("answers][0]['answer'", t('No answers.'));
  }
  if ($answers < 2) {
    form_set_error("answers][1]['answer'", t('Must have at least two answers.'));
  }
}

/**
 * Implementation of hook_insert().
 */
function multichoice_insert(&$node) {
  db_query("INSERT INTO {quiz_question} (nid, properties) VALUES(%d, '%s')", $node->nid, serialize(array(
    'multiple_answers' => $node->multiple_answers,
  )));

  // we came from editing a quiz, so we should add this question to the quiz directly
  if ($node->quiz_id > 0) {
    db_query('INSERT INTO {quiz_questions} (quiz_nid, question_nid, question_status) VALUES (%d, %d, %d)', $node->quiz_id, $node->nid, QUESTION_ALWAYS);
  }
  while (list($key, $value) = each($node->answers)) {
    if (trim($value['answer']) != "") {
      db_query("INSERT INTO {quiz_question_answer} (aid, question_nid, answer, feedback, points) VALUES(%d, %d, '%s', '%s', %d)", db_next_id('{quiz_question_answer}_aid'), $node->nid, $value['answer'], $value['feedback'], $value['correct']);
    }
  }
}

/**
 * Implementation of hook_update().
 */
function multichoice_update($node) {
  db_query("UPDATE {quiz_question} SET properties = '%s' WHERE nid = %d", serialize(array(
    'multiple_answers' => $node->multiple_answers,
  )), $node->nid);
  while (list($key, $value) = each($node->answers)) {
    if ($value['aid']) {
      $value['answer'] = trim($value['answer']);
      if ($value['delete'] == 1 || !isset($value['answer']) || $value['answer'] == '') {

        //Delete this entry
        db_query("DELETE FROM {quiz_question_answer} WHERE aid = %d", $value['aid']);
      }
      else {

        //Update this entry
        db_query("UPDATE {quiz_question_answer} SET answer = '%s', feedback = '%s', points = %s WHERE aid = %d", $value['answer'], $value['feedback'], $value['correct'], $value['aid']);
      }
    }
    else {
      if (trim($value['answer']) != "") {

        //If there is an answer, insert a new row
        db_query("INSERT INTO {quiz_question_answer} (aid, question_nid, answer, feedback, points) VALUES(%d, %d, '%s', '%s', %d)", db_next_id('{quiz_question_answer}_aid'), $node->nid, $value['answer'], $value['feedback'], $value['correct']);
      }
    }
  }
}

/**
 * Implementation of hook_delete().
 */
function multichoice_delete(&$node) {

  // for all quizzes that have this quiz with status ALWAYS, reduce number of questions by 1
  db_query("UPDATE {quiz} SET number_of_questions = number_of_questions-1 WHERE nid IN (SELECT quiz_nid FROM {quiz_questions} WHERE question_status = %d AND question_nid = %d)", QUESTION_ALWAYS, $node->nid);

  // delete all answers for this question
  db_query("DELETE FROM {quiz_question_answer} WHERE question_nid = %d", $node->nid);

  // delete this question from all quizzes
  db_query("DELETE FROM {quiz_question} WHERE nid = %d", $node->nid);
  db_query("DELETE FROM {quiz_questions} WHERE question_nid = %d", $node->nid);
}

/**
 * Implementation of hook_load().
 */
function multichoice_load($node) {
  $additions = db_fetch_object(db_query("SELECT * FROM {quiz_question} WHERE nid = %d", $node->nid));
  $answers = array();
  $result = db_query("SELECT * FROM {quiz_question_answer} WHERE question_nid = %d", $node->nid);
  while ($line = db_fetch_array($result)) {
    $answers[] = $line;
  }
  $additions->answers = $answers;
  $additions->properties = unserialize($additions->properties);
  $additions->multiple_answers = $additions->properties['multiple_answers'];
  return $additions;
}

/**
 * Implementation of hook_view().
 */
function multichoice_view(&$node, $teaser = FALSE, $page = FALSE) {
  if (user_access('create multichoice')) {
    if (!$teaser) {
      $mynode = node_prepare($node, $teaser);
      $mynode->content['body'] = array(
        '#value' => multichoice_render_question($node),
      );
      return $mynode;

      //$node->body = multichoice_render_question($node);
    }
  }
  else {
    if ($teaser) {
      $mynode = node_prepare($node, $teaser);
      return $mynode;

      //$node->teaser = t('This is a quiz question, not to be viewed independently.');

      //$node->body = $node->teaser; // we do not need Read more...
    }
    else {
      drupal_access_denied();
    }
  }
}

/**
 * Print question to screen
 *
 * @param $node
 *   Question node
 *
 * @return
 *   HTML output
 */
function multichoice_render_question_form($node) {

  // Radio buttons for single selection questions, checkboxes for multiselect
  if ($node->multiple_answers == 0) {
    $type = 'radios';
  }
  else {
    $type = 'checkboxes';
  }

  // Get options
  $options = array();
  while (list($key, $answer) = each($node->answers)) {
    if (empty($answer['correct']) && !isset($answer['answer']) && empty($answer['feedback'])) {
      unset($node->answers[$key]);
    }
    else {
      $options[$key] = '<div class="multichoice_answer_text">' . check_markup($answer['answer'], $node->format, FALSE) . '</div>';
    }
  }
  $form['start'] = array(
    '#type' => 'markup',
    '#value' => '<div class="multichoice_form">',
  );
  $form['question'] = array(
    '#type' => 'markup',
    '#value' => check_markup($node->body, $node->format, FALSE),
  );

  // Create form
  $form['tries'] = array(
    '#type' => $type,
    '#options' => $options,
    '#default_value' => -1,
  );
  $form['submit'] = array(
    '#type' => 'submit',
    '#value' => t('Submit'),
  );
  return $form;
}
function multichoice_render_question($node) {
  return drupal_get_form('multichoice_render_question_form', $node);
}

/**
 * Evaluate whether question is correct
 *
 * @param $nid
 *   Question Node ID
 *
 * @return
 *   Array of results, in the form of:
 *   array(
 *     'answers' => array of correct answer(s)
 *     'tried' => array of selected answer(s)
 *   );
 */
function multichoice_evaluate_question($nid) {
  $question = node_load($nid);
  $results = array();
  if (isset($_POST['tries'])) {
    if (is_array($_POST['tries'])) {

      // Multi-answer question
      while (list($key, $try) = each($_POST['tries'])) {
        $results['answers'] = $question->answers;
        $results['tried'][] = $question->answers[$try]['aid'];
      }
    }
    else {

      // Single-answer question
      $results['answers'] = $question->answers;
      $results['tried'][] = $question->answers[$_POST['tries']]['aid'];
    }
  }

  //Unset $_POST, otherwise it tries to use the previous answers on the next page...
  unset($_POST['tries']);

  //Return the result
  return $results;
}

/**
 * check if the user selected all the correct answers for this question
 * @param $answers array of answers
 * @param $tried array of answer id's the user selected
 * @return true if the user selected exactly all of the correct answers, otherwise false
 */
function multichoice_calculate_result($answers, $tried) {
  if (empty($answers) || empty($tried)) {
    return FALSE;
  }
  foreach ($answers as $answer) {
    if ($answer['points'] == 1) {
      $correctanswers[] = $answer['aid'];
    }
  }
  return $correctanswers === $tried ? TRUE : FALSE;
}

//New singing and dancing one
function multichoice_calculate_results($answers, $tried, $showpoints = FALSE, $showfeedback = FALSE) {

  //Create results table
  $rows = array();
  $correctanswers = array();
  while (list($key, $answer) = each($answers)) {
    $cols = array();
    $cols[] = $answer['answer'];
    if ($showpoints) {
      $cols[] = $answer['points'] == 0 ? theme_multichoice_unselected() : theme_multichoice_selected();
    }
    $selected = array_search($answer['aid'], $tried) !== FALSE;
    $cols[] = $selected ? theme_multichoice_selected() : theme_multichoice_unselected();
    if ($showfeedback) {
      $cols[] = $selected ? '<div class="quiz_answer_feedback">' . $answer['feedback'] . '</div>' : '';
    }
    $rows[] = $cols;
    if ($answer['points'] > 0) {
      $correctanswers[] = $answer['aid'];
    }
  }
  if ($correctanswers === $tried) {
    $score = 1;
  }
  else {
    $score = 0;
  }
  return array(
    'score' => $score,
    'resultstable' => $rows,
  );
}

/**
 * List all multiple choice questions
 *
 * @return
 *   Array of questions
 */
function multichoice_list_questions() {
  $result = db_query("SELECT nid, body, format FROM {node} WHERE type= '%s'", 'multichoice');
  $questions = array();
  while ($node = db_fetch_object($result)) {
    $question = new stdClass();
    $question->question = check_markup($node->body, $node->format);
    $question->nid = $node->nid;
    $questions[] = $question;
  }
  return $questions;
}

/////////////////////////////////////////////////

/// Theme functions

/////////////////////////////////////////////////

/**
 * Theme function for multichoice form
 *
 * Lays out answer field elements into a table
 *
 * @return string
 *   HTML output
 */
function theme_multichoice_form($form) {

  // Format table header
  $header = array(
    array(
      'data' => t('Correct'),
    ),
    array(
      'data' => t('Answer'),
      'style' => 'width:250px;',
    ),
    array(
      'data' => t('Feedback'),
      'style' => 'width:250px;',
    ),
    array(
      'data' => t('Delete'),
    ),
  );

  // Format table rows
  $rows = array();
  foreach (element_children($form) as $key) {
    $rows[] = array(
      drupal_render($form[$key]['correct']),
      drupal_render($form[$key]['answer']),
      drupal_render($form[$key]['feedback']),
      drupal_render($form[$key]['delete']),
    );
  }

  // Theme output and display to screen
  $output = theme('table', $header, $rows);
  return $output;
}

/**
 * Theme a selection indicator for an answer
 * TODO: Default images would be nice
 */
function theme_multichoice_selected() {
  return theme_image(drupal_get_path('module', 'quiz') . '/images/selected.gif', t('selected'));
}

/**
 * Theme an indicator that an answer is not selected / correct
 * TODO: Default images would be nice
 */
function theme_multichoice_unselected() {
  return theme_image(drupal_get_path('module', 'quiz') . '/images/unselected.gif', t('unselected'));
}

/**
 * Theme function for the multichoice form
 */
function theme_multichoice_render_question_form($form) {
  $output = '';
  $output .= drupal_render($form) . '</div>';
  return $output;
}

Functions

Namesort descending Description
multichoice_access Implementation of hook_access().
multichoice_calculate_result check if the user selected all the correct answers for this question
multichoice_calculate_results
multichoice_delete Implementation of hook_delete().
multichoice_evaluate_question Evaluate whether question is correct
multichoice_form Implementation of hook_form().
multichoice_insert Implementation of hook_insert().
multichoice_list_questions List all multiple choice questions
multichoice_load Implementation of hook_load().
multichoice_menu Implementation of hook_menu().
multichoice_node_info Implementation of hook_node_info().
multichoice_perm Implementation of hook_perm().
multichoice_render_question
multichoice_render_question_form Print question to screen
multichoice_update Implementation of hook_update().
multichoice_validate Implementation of hook_validate().
multichoice_view Implementation of hook_view().
theme_multichoice_form Theme function for multichoice form
theme_multichoice_render_question_form Theme function for the multichoice form
theme_multichoice_selected Theme a selection indicator for an answer TODO: Default images would be nice
theme_multichoice_unselected Theme an indicator that an answer is not selected / correct TODO: Default images would be nice

Constants

Namesort descending Description
MULTICHOICE_NAME