为什么选择正确答案时返回false？我有问题和答案。问题和答案是随机的。有一个问题和四个答案。当我选择corrrect answer时，它返回false。为什么会这样？我正在试着解决这个问题。我不明白为什么会这样。如何解决这个问题？

var characters = ['a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z',];
final random = Random();
var randomElement = characters[random.nextInt(characters.length)];
var randomElement2 = characters[random.nextInt(characters.length)];
var randomElement3 = characters[random.nextInt(characters.length)];
var randomElement4 = characters[random.nextInt(characters.length)];
var answers = [randomElement, randomElement2, randomElement3, randomElement4];

class MyHomePage extends StatefulWidget {
  MyHomePage({super.key});

  @override
  State<MyHomePage> createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  int selectedIndex = -1;

  @override
  Widget build(BuildContext context) {
    return SafeArea(
      child: SingleChildScrollView(
        physics: ScrollPhysics(),
        child: Column(
          children: [
            Text(
              'Select: $randomElement',
              style: TextStyle(fontSize: 22),
            ),
            ListView.builder(
                physics: NeverScrollableScrollPhysics(),
                shrinkWrap: true,
                itemCount: answers.length,
                itemBuilder: (BuildContext context, int index) {
                  return ElevatedButton(
                    style: ElevatedButton.styleFrom(
                      backgroundColor:
                          selectedIndex == index ? Colors.grey : Colors.white,
                    ),
                    onPressed: () {
                      setState(() {
                        selectedIndex = index;
                      });
                    },
                    child: Text(
                      answers[index],
                    ),
                  );
                }),
            ElevatedButton(
              onPressed: () {
                setState(() {
                  randomElement = characters[random.nextInt(characters.length)];
                });
                randomElement2 = characters[random.nextInt(characters.length)];
                randomElement3 = characters[random.nextInt(characters.length)];
                randomElement4 = characters[random.nextInt(characters.length)];
                setState(() {
                  answers = [
                    randomElement,
                    randomElement2,
                    randomElement3,
                    randomElement4
                  ];
                });
                answers.shuffle();
                if (randomElement == answers[selectedIndex]) {
                  debugPrint('correct');
                } else {
                  debugPrint('false');
                }
                selectedIndex = -1;
              },
              child: Text('Next'),
            )
          ],
        ),
      ),
    );
  }
}