獲取此RangeError（索引）：無效值：有效值范圍為空：1嘗試將json資料填充到ListView.builder

我有一個 API，我想做的是'CourseTitle'將 JSON 中的內容顯示到ExpansionTile標題中，并在 ExpansionTile 的子項中顯示相應的“Title”、“EndDate”、“QuizStatus”。

如果對應的“Title”、“EndDate”、“QuizStatus”等資料不可用，則僅應將“CourseTitle”添加到 ExpansionTile 標題中，并且 children 應為空。

第一個圖塊按預期構建，但其余螢屏顯示紅色螢屏，帶有RangeError (index): Invalid value: Valid value range is empty: 1.

我知道這是因為 JSON 中的資料為空，但無法解決問題。

這是 JSON 回應：

{
    "QuizzesData": [
        {
            "request_status": "Successful",
            "CourseCode": "ABC101",
            "CourseTitle": "ABC Course",
            "UnReadStatus": [],
            "Quizzes": [
                {
                    "QuizID": "542",
                    "Title": "Test Quiz 01",
                    "StartDate": "Oct 20, 2022 12:00 AM",
                    "EndDate": "Oct 31, 2022 11:59 PM",
                    "IsDeclared": "False",
                    "Questions": "5",
                    "TotalMarks": "5",
                    "MarksObtained": "1",
                    "MarksObtainedTOCheckQuizResult": "1",
                    "QuizIsDeclared": "Un-Declared",
                    "StudentSubmitStatus": "true",
                    "IsRead": "1",
                    "QuizStatus": "Attempted"
                }
            ]
        },
        {
            "CourseCode": "DEF101",
            "CourseTitle": "DEF Course",
            "UnReadStatus": [],
            "Quizzes": []
        },
        {
            "CourseCode": "GHI101",
            "CourseTitle": "GHI Course",
            "UnReadStatus": [],
            "Quizzes": []
        },
        {
            "CourseCode": "JKL101",
            "CourseTitle": "JKL Course",
            "UnReadStatus": [],
            "Quizzes": []
        },
 
    ]
}

這是 API 資料：

  var listofdata ;
  Future quizListingApi() async {
    final response = await http.get(Uri.parse('json url'));
    if(response.statusCode == 200){
       listofdata = jsonDecode(response.body.toString());
     }
     else{
    print(response.statusCode);
     }

和構建方法：

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Column(
        children: [
          Expanded(child: FutureBuilder(
            future: quizListingApi(),
            builder: (context, AsyncSnapshot snapshot){
              if(snapshot.connectionState == ConnectionState.waiting){
                return Text('Loading');
              }
              else{
                return ListView.builder(
                  itemCount: listofdata['QuizzesData'].length,
                    itemBuilder: (context, index){
                    return Card(
                      child: Column(
                        children: [
                          ExpansionTile(
                              title: Text(listofdata['QuizzesData'][index]['CourseTitle']),
                            children: [
                              Text(listofdata['QuizzesData'][index]['Quizzes'][index]['Title']),
                              Text(listofdata['QuizzesData'][index]['Quizzes'][index]['EndDate']),
                              Text(listofdata['QuizzesData'][index]['Quizzes'][index]['QuizStatus']),
                            ],
                          ),
                        ],
                      ),
                    );
                    }
                );
              }
            },
          ))
        ],
      ),
    );
  }

我還嘗試了其他類似執行緒的答案，但找不到這種特定型別問題的解決方案。

uj5u.com熱心網友回復：

您的Quizzes's索引與您的不同listofdata，因此您需要和其他 for 回圈為您的Quizzes's專案：

ExpansionTile(
  title: Text(listofdata['QuizzesData'][index]['CourseTitle']),
  children: List<Widget>.generate(listofdata['QuizzesData'][index]['Quizzes'].length, (i) => Column(
    children: [
        Text(listofdata['QuizzesData'][index]['Quizzes'][i]
        ['Title']),
    Text(listofdata['QuizzesData'][index]['Quizzes'][i]
        ['EndDate']),
    Text(listofdata['QuizzesData'][index]['Quizzes'][i]
        ['QuizStatus']),
    ],
  ),),
),

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