如果提交为空如何修复它仍然会转到 php 中的另一个问题

Question

我正在尝试做一个测验，测验已经完成了，但是有一个问题我正在尝试解决，但我自己无法解决。

我试过当我的问题从空的表格提交时它仍然会继续下一个问题。

代码：

public function getHTML()
     {
         self::getCurrentQuestion();
         $choices = '';
         foreach ($this->questions[$this->currentQuestionNumber]->giveAnswers() as $answerChoice) {
             $choices .= '<input type="radio" value="' . $answerChoice->getText() . '" name="answer"/>' . $answerChoice->getText() . '<br>
                 ';
         }

         $form = ' <form method="POST">
         <h1>Question: ' . $this->ask[$this->currentQuestionNumber]->giveQuestionNumber() . '</h1>
        
         <h2>' . $this->ask[$this->currentQuestionNumber]->giveText() . '</h2>

         <input type="hidden" name="questions completed" value="' . htmlspecialchars(json_encode($this->questions completed)) . '">

         <input type="hidden" name="counter" id="counter" value="' . $this->currentQuestionNumber . '">

         '. $choices . '

         <br>
         <input type="submit" value="Submit">
         </form>
         <br>
         ';
         return $form;
     }
//the questions
$this->questions = [
             new Question(1, "ork ork ork Soup do you eat with a?", [new Answer("fork", false), new Answer("spoon", true), new Answer("Knife", false), new Answer ("chopsticks", false)]),
             new Question(2, "chicken soup is made of?", [new Answer("pig", false), new Answer("chicken", true), new Answer("cow", false)]),
             new Question(3, "Is cheese cheese?", [new Answer("no", false), new Answer("yes", true), new Answer("Maybe", false)]),
             new Question(4, "Does this new function I just created work?", [new Answer("no", false), new Answer("yes", true)]),
             new Question(5, "An egg hatches from one?", [new Answer("horse", false), new Answer("chicken", true), new Answer("cow", false)]),
             new Question(6, "Is the quiz working?", [new Answer("yes", true), new Answer("no", false)]),
             new Question(7, "what is 200-10", [new Answer("180", false), new Answer("200", false), new Answer("190", true), new Answer("210" , false), new Answer("170", false) ])
         ];

我的解决方案

public function isQuestionSubmittedEmpty($question)
     {
         $answer = $question->getAnswer();
         foreach ($answer as $answer) {
             if (!empty($answer->getAnswer())) {
                 return false;
             }
         }
         return true;
     }

我已经尝试过 foreach 问题，如果它提交的是空的，它仍然会继续下一个问题，但也许它可以用 isset POST 函数修复。

因为每次我点击提交按钮它都会自动回到第一个问题