View source for Development:Questiontype creation to delete

{{Convert question bank}}
{{Questiontype class}}
==functions related to create, editing and deleting questions==
first draw [[User:Pierre Pichet|Pierre Pichet]] 10:45, 17 March 2007 (CDT)
==function create_editing_form($submiturl, $question)==
    /**
     * Return an instance of the question editing form definition. This looks for a
     * class called edit_{$this->name()}_question_form in the file
     * {$CFG->docroot}/question/type/{$this->name()}/edit_{$this->name()}_question_form.php
     * and if it exists returns an instance of it.
     *
     * @param string $submiturl passed on to the constructor call.
     * @return object an instance of the form definition, or null if one could not be found.
     */
    function create_editing_form($submiturl, $question) {
        global $CFG;
        require_once("{$CFG->dirroot}/question/type/edit_question_form.php");
        $definition_file = $CFG->dirroot.'/question/type/'.$this->name().'/edit_'.$this->name().'_form.php';
        if (!(is_readable($definition_file) && is_file($definition_file))) {
            return null;
        }
        require_once($definition_file);
        $classname = 'question_edit_'.$this->name().'_form';
        if (!class_exists($classname)) {
            return null;
        }
        return new $classname($submiturl, $question);
    }
==function display_question_editing_page(&$mform, $question, $wizardnow)==
    /**
     * This method should be overriden if you want to include a special heading or some other
     * html on a question editing page besides the question editing form.
     *
     * @param question_edit_form $mform a child of question_edit_form
     * @param object $question
     * @param string $wizardnow is '' for first page.
     */
    function display_question_editing_page(&$mform, $question, $wizardnow){

        print_heading_with_help(get_string("editing".$question->qtype, "quiz"), $question->qtype, "quiz");

        $mform->display();

    }
==function save_question($question, $form, $course)==
    /**
    * Saves or updates a question after editing by a teacher
    *
    * Given some question info and some data about the answers
    * this function parses, organises and saves the question
    * It is used by {@link question.php} when saving new data from
    * a form, and also by {@link import.php} when importing questions
    * This function in turn calls {@link save_question_options}
    * to save question-type specific options
    * @param object $question the question object which should be updated
    * @param object $form the form submitted by the teacher
    * @param object $course the course we are in
    * @return object On success, return the new question object. On failure,
    *       return an object as follows. If the error object has an errors field,
    *       display that as an error message. Otherwise, the editing form will be
    *       redisplayed with validation errors, from validation_errors field, which
    *       is itself an object, shown next to the form fields.
    */
    function save_question($question, $form, $course) {
        // This default implementation is suitable for most
        // question types.

        // First, save the basic question itself
        $question->name               = trim($form->name);
        $question->questiontext       = trim($form->questiontext);
        $question->questiontextformat = $form->questiontextformat;
        $question->parent             = isset($form->parent)? $form->parent : 0;
        $question->length = $this->actual_number_of_questions($question);
        $question->penalty = isset($form->penalty) ? $form->penalty : 0;

        if (empty($form->image)) {
            $question->image = "";
        } else {
            $question->image = $form->image;
        }

        if (empty($form->generalfeedback)) {
            $question->generalfeedback = '';
        } else {
            $question->generalfeedback = trim($form->generalfeedback);
        }

        if (empty($question->name)) {
            $question->name = substr(strip_tags($question->questiontext), 0, 15);
            if (empty($question->name)) {
                $question->name = '-';
            }
        }

        if ($question->penalty > 1 or $question->penalty < 0) {
            $question->errors['penalty'] = get_string('invalidpenalty', 'quiz');
        }

        if (isset($form->defaultgrade)) {
            $question->defaultgrade = $form->defaultgrade;
        }

        if (!empty($question->id)) { // Question already exists
            // keep existing unique stamp code
            $question->stamp = get_field('question', 'stamp', 'id', $question->id);
            if (!update_record("question", $question)) {
                error("Could not update question!");
            }
        } else {         // Question is a new one
            // Set the unique code
            $question->stamp = make_unique_id_code();
            if (!$question->id = insert_record("question", $question)) {
                error("Could not insert new question!");
            }
        }

        // Now to save all the answers and type-specific options

        $form->id = $question->id;
        $form->qtype = $question->qtype;
        $form->category = $question->category;
        $form->questiontext = $question->questiontext;

        $result = $this->save_question_options($form);

        if (!empty($result->error)) {
            error($result->error);
        }

        if (!empty($result->notice)) {
            notice($result->notice, "question.php?id=$question->id");
        }

        if (!empty($result->noticeyesno)) {
            notice_yesno($result->noticeyesno, "question.php?id=$question->id&amp;courseid={$course->id}",
                "edit.php?courseid={$course->id}");
            print_footer($course);
            exit;
        }

        // Give the question a unique version stamp determined by question_hash()
        if (!set_field('question', 'version', question_hash($question), 'id', $question->id)) {
            error('Could not update question version field');
        }

        return $question;
    }
==function save_question_options($question)==
    /**
    * Saves question-type specific options
    *
    * This is called by {@link save_question()} to save the question-type specific data
    * @return object $result->error or $result->noticeyesno or $result->notice
    * @param object $question  This holds the information from the editing form,
    *                          it is not a standard question object.
    */
    function save_question_options($question) {
        return null;
    }
==function replace_question_in_attempts($oldquestionid, $newquestion, $attemtps)==
    /**
    * Changes all states for the given attempts over to a new question
    *
    * This is used by the versioning code if the teacher requests that a question
    * gets replaced by the new version. In order for the attempts to be regraded
    * properly all data in the states referring to the old question need to be
    * changed to refer to the new version instead. In particular for question types
    * that use the answers table the answers belonging to the old question have to
    * be changed to those belonging to the new version.
    *
    * @param integer $oldquestionid  The id of the old question
    * @param object $newquestion    The new question
    * @param array  $attempts       An array of all attempt objects in whose states
    *                               replacement should take place
    */
    function replace_question_in_attempts($oldquestionid, $newquestion, $attemtps) {
        echo 'Not yet implemented';
        return;
    }
==function get_question_options(&$question)==
    /**
    * Loads the question type specific options for the question.
    *
    * This function loads any question type specific options for the
    * question from the database into the question object. This information
    * is placed in the $question->options field. A question type is
    * free, however, to decide on a internal structure of the options field.
    * @return bool            Indicates success or failure.
    * @param object $question The question object for the question. This object
    *                         should be updated to include the question type
    *                         specific information (it is passed by reference).
    */
    function get_question_options(&$question) {
        if (!isset($question->options)) {
            $question->options = new object;
        }
        // The default implementation attaches all answers for this question
        $question->options->answers = get_records('question_answers', 'question', $question->id, 'id ASC');
        return true;
    }