question/type/multichoice/question.php

   1 <?php
   2 // This file is part of Moodle - http://moodle.org/
   3 //
   4 // Moodle is free software: you can redistribute it and/or modify
   5 // it under the terms of the GNU General Public License as published by
   6 // the Free Software Foundation, either version 3 of the License, or
   7 // (at your option) any later version.
   8 //
   9 // Moodle is distributed in the hope that it will be useful,
  10 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 // GNU General Public License for more details.
  13 //
  14 // You should have received a copy of the GNU General Public License
  15 // along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
  16
  17 /**
  18  * Multiple choice question definition classes.
  19  *
  20  * @package    qtype
  21  * @subpackage multichoice
  22  * @copyright  2009 The Open University
  23  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  24  */
  25
  26
  27 defined('MOODLE_INTERNAL') || die();
  28
  29
  30 /**
  31  * Base class for multiple choice questions. The parts that are common to
  32  * single select and multiple select.
  33  *
  34  * @copyright  2009 The Open University
  35  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  36  */
  37 abstract class qtype_multichoice_base extends question_graded_automatically {
  38     const LAYOUT_DROPDOWN = 0;
  39     const LAYOUT_VERTICAL = 1;
  40     const LAYOUT_HORIZONTAL = 2;
  41
  42     public $answers;
  43
  44     public $shuffleanswers;
  45     public $answernumbering;
  46     public $layout = self::LAYOUT_VERTICAL;
  47
  48     public $correctfeedback;
  49     public $correctfeedbackformat;
  50     public $partiallycorrectfeedback;
  51     public $partiallycorrectfeedbackformat;
  52     public $incorrectfeedback;
  53     public $incorrectfeedbackformat;
  54
  55     protected $order = null;
  56
  57     public function start_attempt(question_attempt_step $step, $variant) {
  58         $this->order = array_keys($this->answers);
  59         if ($this->shuffleanswers) {
  60             shuffle($this->order);
  61         }
  62         $step->set_qt_var('_order', implode(',', $this->order));
  63     }
  64
  65     public function apply_attempt_state(question_attempt_step $step) {
  66         $this->order = explode(',', $step->get_qt_var('_order'));
  67     }
  68
  69     public function get_question_summary() {
  70         $question = $this->html_to_text($this->questiontext, $this->questiontextformat);
  71         $choices = array();
  72         foreach ($this->order as $ansid) {
  73             $choices[] = $this->html_to_text($this->answers[$ansid]->answer,
  74                     $this->answers[$ansid]->answerformat);
  75         }
  76         return $question . ': ' . implode('; ', $choices);
  77     }
  78
  79     public function get_order(question_attempt $qa) {
  80         $this->init_order($qa);
  81         return $this->order;
  82     }
  83
  84     protected function init_order(question_attempt $qa) {
  85         if (is_null($this->order)) {
  86             $this->order = explode(',', $qa->get_step(0)->get_qt_var('_order'));
  87         }
  88     }
  89
  90     public abstract function get_response(question_attempt $qa);
  91
  92     public abstract function is_choice_selected($response, $value);
  93
  94     public function check_file_access($qa, $options, $component, $filearea, $args, $forcedownload) {
  95         if ($component == 'question' && in_array($filearea,
  96                 array('correctfeedback', 'partiallycorrectfeedback', 'incorrectfeedback'))) {
  97             return $this->check_combined_feedback_file_access($qa, $options, $filearea);
  98
  99         } else if ($component == 'question' && $filearea == 'answer') {
 100             $answerid = reset($args); // Itemid is answer id.
 101             return  in_array($answerid, $this->order);
 102
 103         } else if ($component == 'question' && $filearea == 'answerfeedback') {
 104             $answerid = reset($args); // Itemid is answer id.
 105             $response = $this->get_response($qa);
 106             $isselected = false;
 107             foreach ($this->order as $value => $ansid) {
 108                 if ($ansid == $answerid) {
 109                     $isselected = $this->is_choice_selected($response, $value);
 110                     break;
 111                 }
 112             }
 113             // Param $options->suppresschoicefeedback is a hack specific to the
 114             // oumultiresponse question type. It would be good to refactor to
 115             // avoid refering to it here.
 116             return $options->feedback && empty($options->suppresschoicefeedback) &&
 117                     $isselected;
 118
 119         } else if ($component == 'question' && $filearea == 'hint') {
 120             return $this->check_hint_file_access($qa, $options, $args);
 121
 122         } else {
 123             return parent::check_file_access($qa, $options, $component, $filearea,
 124                     $args, $forcedownload);
 125         }
 126     }
 127
 128     public function make_html_inline($html) {
 129         $html = preg_replace('~\s*<p>\s*~u', '', $html);
 130         $html = preg_replace('~\s*</p>\s*~u', '<br />', $html);
 131         $html = preg_replace('~(<br\s*/?>)+$~u', '', $html);
 132         return trim($html);
 133     }
 134 }
 135
 136
 137 /**
 138  * Represents a multiple choice question where only one choice should be selected.
 139  *
 140  * @copyright  2009 The Open University
 141  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 142  */
 143 class qtype_multichoice_single_question extends qtype_multichoice_base {
 144     public function get_renderer(moodle_page $page) {
 145         return $page->get_renderer('qtype_multichoice', 'single');
 146     }
 147
 148     public function get_min_fraction() {
 149         $minfraction = 0;
 150         foreach ($this->answers as $ans) {
 151             $minfraction = min($minfraction, $ans->fraction);
 152         }
 153         return $minfraction;
 154     }
 155
 156     /**
 157      * Return an array of the question type variables that could be submitted
 158      * as part of a question of this type, with their types, so they can be
 159      * properly cleaned.
 160      * @return array variable name => PARAM_... constant.
 161      */
 162     public function get_expected_data() {
 163         return array('answer' => PARAM_INT);
 164     }
 165
 166     public function summarise_response(array $response) {
 167         if (!array_key_exists('answer', $response) ||
 168                 !array_key_exists($response['answer'], $this->order)) {
 169             return null;
 170         }
 171         $ansid = $this->order[$response['answer']];
 172         return $this->html_to_text($this->answers[$ansid]->answer,
 173                 $this->answers[$ansid]->answerformat);
 174     }
 175
 176     public function classify_response(array $response) {
 177         if (!array_key_exists('answer', $response) ||
 178                 !array_key_exists($response['answer'], $this->order)) {
 179             return array($this->id => question_classified_response::no_response());
 180         }
 181         $choiceid = $this->order[$response['answer']];
 182         $ans = $this->answers[$choiceid];
 183         return array($this->id => new question_classified_response($choiceid,
 184                 $this->html_to_text($ans->answer, $ans->answerformat), $ans->fraction));
 185     }
 186
 187     public function get_correct_response() {
 188         foreach ($this->order as $key => $answerid) {
 189             if (question_state::graded_state_for_fraction(
 190                     $this->answers[$answerid]->fraction)->is_correct()) {
 191                 return array('answer' => $key);
 192             }
 193         }
 194         return array();
 195     }
 196
 197
 198     public function prepare_simulated_post_data($simulatedresponse) {
 199         $ansnumbertoanswerid = array_keys($this->answers);
 200         $ansid = $ansnumbertoanswerid[$simulatedresponse['answer']];
 201         return array('answer' => array_search($ansid, $this->order));
 202     }
 203
 204     public function is_same_response(array $prevresponse, array $newresponse) {
 205         return question_utils::arrays_same_at_key($prevresponse, $newresponse, 'answer');
 206     }
 207
 208     public function is_complete_response(array $response) {
 209         return array_key_exists('answer', $response) && $response['answer'] !== '';
 210     }
 211
 212     public function is_gradable_response(array $response) {
 213         return $this->is_complete_response($response);
 214     }
 215
 216     public function grade_response(array $response) {
 217         if (array_key_exists('answer', $response) &&
 218                 array_key_exists($response['answer'], $this->order)) {
 219             $fraction = $this->answers[$this->order[$response['answer']]]->fraction;
 220         } else {
 221             $fraction = 0;
 222         }
 223         return array($fraction, question_state::graded_state_for_fraction($fraction));
 224     }
 225
 226     public function get_validation_error(array $response) {
 227         if ($this->is_gradable_response($response)) {
 228             return '';
 229         }
 230         return get_string('pleaseselectananswer', 'qtype_multichoice');
 231     }
 232
 233     public function get_response(question_attempt $qa) {
 234         return $qa->get_last_qt_var('answer', -1);
 235     }
 236
 237     public function is_choice_selected($response, $value) {
 238         return (string) $response === (string) $value;
 239     }
 240 }
 241
 242
 243 /**
 244  * Represents a multiple choice question where multiple choices can be selected.
 245  *
 246  * @copyright  2009 The Open University
 247  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 248  */
 249 class qtype_multichoice_multi_question extends qtype_multichoice_base {
 250     public function get_renderer(moodle_page $page) {
 251         return $page->get_renderer('qtype_multichoice', 'multi');
 252     }
 253
 254     public function get_min_fraction() {
 255         return 0;
 256     }
 257
 258     public function clear_wrong_from_response(array $response) {
 259         foreach ($this->order as $key => $ans) {
 260             if (array_key_exists($this->field($key), $response) &&
 261                     question_state::graded_state_for_fraction(
 262                     $this->answers[$ans]->fraction)->is_incorrect()) {
 263                 $response[$this->field($key)] = 0;
 264             }
 265         }
 266         return $response;
 267     }
 268
 269     public function get_num_parts_right(array $response) {
 270         $numright = 0;
 271         foreach ($this->order as $key => $ans) {
 272             $fieldname = $this->field($key);
 273             if (!array_key_exists($fieldname, $response) || !$response[$fieldname]) {
 274                 continue;
 275             }
 276
 277             if (!question_state::graded_state_for_fraction(
 278                     $this->answers[$ans]->fraction)->is_incorrect()) {
 279                 $numright += 1;
 280             }
 281         }
 282         return array($numright, count($this->order));
 283     }
 284
 285     /**
 286      * @param int $key choice number
 287      * @return string the question-type variable name.
 288      */
 289     protected function field($key) {
 290         return 'choice' . $key;
 291     }
 292
 293     public function get_expected_data() {
 294         $expected = array();
 295         foreach ($this->order as $key => $notused) {
 296             $expected[$this->field($key)] = PARAM_BOOL;
 297         }
 298         return $expected;
 299     }
 300
 301     public function summarise_response(array $response) {
 302         $selectedchoices = array();
 303         foreach ($this->order as $key => $ans) {
 304             $fieldname = $this->field($key);
 305             if (array_key_exists($fieldname, $response) && $response[$fieldname]) {
 306                 $selectedchoices[] = $this->html_to_text($this->answers[$ans]->answer,
 307                         $this->answers[$ans]->answerformat);
 308             }
 309         }
 310         if (empty($selectedchoices)) {
 311             return null;
 312         }
 313         return implode('; ', $selectedchoices);
 314     }
 315
 316     public function classify_response(array $response) {
 317         $selectedchoices = array();
 318         foreach ($this->order as $key => $ansid) {
 319             $fieldname = $this->field($key);
 320             if (array_key_exists($fieldname, $response) && $response[$fieldname]) {
 321                 $selectedchoices[$ansid] = 1;
 322             }
 323         }
 324         $choices = array();
 325         foreach ($this->answers as $ansid => $ans) {
 326             if (isset($selectedchoices[$ansid])) {
 327                 $choices[$ansid] = new question_classified_response($ansid,
 328                         $this->html_to_text($ans->answer, $ans->answerformat), $ans->fraction);
 329             }
 330         }
 331         return $choices;
 332     }
 333
 334     public function get_correct_response() {
 335         $response = array();
 336         foreach ($this->order as $key => $ans) {
 337             if (!question_state::graded_state_for_fraction(
 338                     $this->answers[$ans]->fraction)->is_incorrect()) {
 339                 $response[$this->field($key)] = 1;
 340             }
 341         }
 342         return $response;
 343     }
 344
 345     public function prepare_simulated_post_data($simulatedresponse) {
 346         $postdata = array();
 347         $ansidtochoiceno = array_flip($this->order);
 348         ksort($ansidtochoiceno, SORT_NUMERIC);
 349         $ansnotochoiceno = array_values($ansidtochoiceno);
 350         foreach ($simulatedresponse as $ansno => $checked) {
 351             $postdata[$this->field($ansnotochoiceno[$ansno])] = $checked;
 352         }
 353         return $postdata;
 354     }
 355
 356     public function is_same_response(array $prevresponse, array $newresponse) {
 357         foreach ($this->order as $key => $notused) {
 358             $fieldname = $this->field($key);
 359             if (!question_utils::arrays_same_at_key_integer($prevresponse, $newresponse, $fieldname)) {
 360                 return false;
 361             }
 362         }
 363         return true;
 364     }
 365
 366     public function is_complete_response(array $response) {
 367         foreach ($this->order as $key => $notused) {
 368             if (!empty($response[$this->field($key)])) {
 369                 return true;
 370             }
 371         }
 372         return false;
 373     }
 374
 375     public function is_gradable_response(array $response) {
 376         return $this->is_complete_response($response);
 377     }
 378
 379     /**
 380      * @param array $response responses, as returned by
 381      *      {@link question_attempt_step::get_qt_data()}.
 382      * @return int the number of choices that were selected. in this response.
 383      */
 384     public function get_num_selected_choices(array $response) {
 385         $numselected = 0;
 386         foreach ($response as $key => $value) {
 387             if (!empty($value)) {
 388                 $numselected += 1;
 389             }
 390         }
 391         return $numselected;
 392     }
 393
 394     /**
 395      * @return int the number of choices that are correct.
 396      */
 397     public function get_num_correct_choices() {
 398         $numcorrect = 0;
 399         foreach ($this->answers as $ans) {
 400             if (!question_state::graded_state_for_fraction($ans->fraction)->is_incorrect()) {
 401                 $numcorrect += 1;
 402             }
 403         }
 404         return $numcorrect;
 405     }
 406
 407     public function grade_response(array $response) {
 408         $fraction = 0;
 409         foreach ($this->order as $key => $ansid) {
 410             if (!empty($response[$this->field($key)])) {
 411                 $fraction += $this->answers[$ansid]->fraction;
 412             }
 413         }
 414         $fraction = min(max(0, $fraction), 1.0);
 415         return array($fraction, question_state::graded_state_for_fraction($fraction));
 416     }
 417
 418     public function get_validation_error(array $response) {
 419         if ($this->is_gradable_response($response)) {
 420             return '';
 421         }
 422         return get_string('pleaseselectatleastoneanswer', 'qtype_multichoice');
 423     }
 424
 425     /**
 426      * Disable those hint settings that we don't want when the student has selected
 427      * more choices than the number of right choices. This avoids giving the game away.
 428      * @param question_hint_with_parts $hint a hint.
 429      */
 430     protected function disable_hint_settings_when_too_many_selected(
 431             question_hint_with_parts $hint) {
 432         $hint->clearwrong = false;
 433     }
 434
 435     public function get_hint($hintnumber, question_attempt $qa) {
 436         $hint = parent::get_hint($hintnumber, $qa);
 437         if (is_null($hint)) {
 438             return $hint;
 439         }
 440
 441         if ($this->get_num_selected_choices($qa->get_last_qt_data()) >
 442                 $this->get_num_correct_choices()) {
 443             $hint = clone($hint);
 444             $this->disable_hint_settings_when_too_many_selected($hint);
 445         }
 446         return $hint;
 447     }
 448
 449     public function get_response(question_attempt $qa) {
 450         return $qa->get_last_qt_data();
 451     }
 452
 453     public function is_choice_selected($response, $value) {
 454         return !empty($response['choice' . $value]);
 455     }
 456 }