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             // $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     public function is_same_response(array $prevresponse, array $newresponse) {
 198         return question_utils::arrays_same_at_key($prevresponse, $newresponse, 'answer');
 199     }
 200
 201     public function is_complete_response(array $response) {
 202         return array_key_exists('answer', $response) && $response['answer'] !== '';
 203     }
 204
 205     public function is_gradable_response(array $response) {
 206         return $this->is_complete_response($response);
 207     }
 208
 209     public function grade_response(array $response) {
 210         if (array_key_exists('answer', $response) &&
 211                 array_key_exists($response['answer'], $this->order)) {
 212             $fraction = $this->answers[$this->order[$response['answer']]]->fraction;
 213         } else {
 214             $fraction = 0;
 215         }
 216         return array($fraction, question_state::graded_state_for_fraction($fraction));
 217     }
 218
 219     public function get_validation_error(array $response) {
 220         if ($this->is_gradable_response($response)) {
 221             return '';
 222         }
 223         return get_string('pleaseselectananswer', 'qtype_multichoice');
 224     }
 225
 226     public function get_response(question_attempt $qa) {
 227         return $qa->get_last_qt_var('answer', -1);
 228     }
 229
 230     public function is_choice_selected($response, $value) {
 231         return (string) $response === (string) $value;
 232     }
 233 }
 234
 235
 236 /**
 237  * Represents a multiple choice question where multiple choices can be selected.
 238  *
 239  * @copyright  2009 The Open University
 240  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 241  */
 242 class qtype_multichoice_multi_question extends qtype_multichoice_base {
 243     public function get_renderer(moodle_page $page) {
 244         return $page->get_renderer('qtype_multichoice', 'multi');
 245     }
 246
 247     public function get_min_fraction() {
 248         return 0;
 249     }
 250
 251     public function clear_wrong_from_response(array $response) {
 252         foreach ($this->order as $key => $ans) {
 253             if (array_key_exists($this->field($key), $response) &&
 254                     question_state::graded_state_for_fraction(
 255                     $this->answers[$ans]->fraction)->is_incorrect()) {
 256                 $response[$this->field($key)] = 0;
 257             }
 258         }
 259         return $response;
 260     }
 261
 262     public function get_num_parts_right(array $response) {
 263         $numright = 0;
 264         foreach ($this->order as $key => $ans) {
 265             $fieldname = $this->field($key);
 266             if (!array_key_exists($fieldname, $response) || !$response[$fieldname]) {
 267                 continue;
 268             }
 269
 270             if (!question_state::graded_state_for_fraction(
 271                     $this->answers[$ans]->fraction)->is_incorrect()) {
 272                 $numright += 1;
 273             }
 274         }
 275         return array($numright, count($this->order));
 276     }
 277
 278     /**
 279      * @param int $key choice number
 280      * @return string the question-type variable name.
 281      */
 282     protected function field($key) {
 283         return 'choice' . $key;
 284     }
 285
 286     public function get_expected_data() {
 287         $expected = array();
 288         foreach ($this->order as $key => $notused) {
 289             $expected[$this->field($key)] = PARAM_BOOL;
 290         }
 291         return $expected;
 292     }
 293
 294     public function summarise_response(array $response) {
 295         $selectedchoices = array();
 296         foreach ($this->order as $key => $ans) {
 297             $fieldname = $this->field($key);
 298             if (array_key_exists($fieldname, $response) && $response[$fieldname]) {
 299                 $selectedchoices[] = $this->html_to_text($this->answers[$ans]->answer,
 300                         $this->answers[$ans]->answerformat);
 301             }
 302         }
 303         if (empty($selectedchoices)) {
 304             return null;
 305         }
 306         return implode('; ', $selectedchoices);
 307     }
 308
 309     public function classify_response(array $response) {
 310         $selectedchoices = array();
 311         foreach ($this->order as $key => $ansid) {
 312             $fieldname = $this->field($key);
 313             if (array_key_exists($fieldname, $response) && $response[$fieldname]) {
 314                 $selectedchoices[$ansid] = 1;
 315             }
 316         }
 317         $choices = array();
 318         foreach ($this->answers as $ansid => $ans) {
 319             if (isset($selectedchoices[$ansid])) {
 320                 $choices[$ansid] = new question_classified_response($ansid,
 321                         $this->html_to_text($ans->answer, $ans->answerformat), $ans->fraction);
 322             }
 323         }
 324         return $choices;
 325     }
 326
 327     public function get_correct_response() {
 328         $response = array();
 329         foreach ($this->order as $key => $ans) {
 330             if (!question_state::graded_state_for_fraction(
 331                     $this->answers[$ans]->fraction)->is_incorrect()) {
 332                 $response[$this->field($key)] = 1;
 333             }
 334         }
 335         return $response;
 336     }
 337
 338     public function is_same_response(array $prevresponse, array $newresponse) {
 339         foreach ($this->order as $key => $notused) {
 340             $fieldname = $this->field($key);
 341             if (!question_utils::arrays_same_at_key($prevresponse, $newresponse, $fieldname)) {
 342                 return false;
 343             }
 344         }
 345         return true;
 346     }
 347
 348     public function is_complete_response(array $response) {
 349         foreach ($this->order as $key => $notused) {
 350             if (!empty($response[$this->field($key)])) {
 351                 return true;
 352             }
 353         }
 354         return false;
 355     }
 356
 357     public function is_gradable_response(array $response) {
 358         return $this->is_complete_response($response);
 359     }
 360
 361     /**
 362      * @param array $response responses, as returned by
 363      *      {@link question_attempt_step::get_qt_data()}.
 364      * @return int the number of choices that were selected. in this response.
 365      */
 366     public function get_num_selected_choices(array $response) {
 367         $numselected = 0;
 368         foreach ($response as $key => $value) {
 369             if (!empty($value)) {
 370                 $numselected += 1;
 371             }
 372         }
 373         return $numselected;
 374     }
 375
 376     /**
 377      * @return int the number of choices that are correct.
 378      */
 379     public function get_num_correct_choices() {
 380         $numcorrect = 0;
 381         foreach ($this->answers as $ans) {
 382             if (!question_state::graded_state_for_fraction($ans->fraction)->is_incorrect()) {
 383                 $numcorrect += 1;
 384             }
 385         }
 386         return $numcorrect;
 387     }
 388
 389     public function grade_response(array $response) {
 390         $fraction = 0;
 391         foreach ($this->order as $key => $ansid) {
 392             if (!empty($response[$this->field($key)])) {
 393                 $fraction += $this->answers[$ansid]->fraction;
 394             }
 395         }
 396         $fraction = min(max(0, $fraction), 1.0);
 397         return array($fraction, question_state::graded_state_for_fraction($fraction));
 398     }
 399
 400     public function get_validation_error(array $response) {
 401         if ($this->is_gradable_response($response)) {
 402             return '';
 403         }
 404         return get_string('pleaseselectatleastoneanswer', 'qtype_multichoice');
 405     }
 406
 407     /**
 408      * Disable those hint settings that we don't want when the student has selected
 409      * more choices than the number of right choices. This avoids giving the game away.
 410      * @param question_hint_with_parts $hint a hint.
 411      */
 412     protected function disable_hint_settings_when_too_many_selected(
 413             question_hint_with_parts $hint) {
 414         $hint->clearwrong = false;
 415     }
 416
 417     public function get_hint($hintnumber, question_attempt $qa) {
 418         $hint = parent::get_hint($hintnumber, $qa);
 419         if (is_null($hint)) {
 420             return $hint;
 421         }
 422
 423         if ($this->get_num_selected_choices($qa->get_last_qt_data()) >
 424                 $this->get_num_correct_choices()) {
 425             $hint = clone($hint);
 426             $this->disable_hint_settings_when_too_many_selected($hint);
 427         }
 428         return $hint;
 429     }
 430
 431     public function get_response(question_attempt $qa) {
 432         return $qa->get_last_qt_data();
 433     }
 434
 435     public function is_choice_selected($response, $value) {
 436         return !empty($response['choice' . $value]);
 437     }
 438 }