for循环只得到最后一个索引不正确的索引颤振

Question

我有一个列表，这个列表格式是按月数据我将按月数据放在列表中但只显示最后一个索引数据而不是正确的数据，如果我在内部打印数据，如果条件打印完美但内部小部件未正确显示。我正在添加一些代码：

声明：

int monthIndex, 
List transactionLists =[];

我的方法：

myMethod(){
    for (var i = 1; i < transactionLists.length; i++) {
      if (monthName[monthIndex] == "July") {
        data=transactionLists[i].july.toString();
         print(data);
      } else if (monthName[monthIndex] == "August") {
        data = transactionLists[i].august.toString();
      } else if (monthName[monthIndex] == "September") {
        data = transactionLists[i].september.toString();
      } else if (monthName[monthIndex] == "October") {
        data = transactionLists[i].october.toString();
      } //.... up to all 12 months
     }
     return ListView.builder(
      padding: EdgeInsets.zero,
      shrinkWrap: true,
      physics: const NeverScrollableScrollPhysics(),
      itemCount: transactionLists.length,
      itemBuilder: (context, childIndex) {
         return Text(
            data,
           );
      }
}

我有什么尝试data[childIndex]

输出 - 1245,1245,1245 为所有索引获得相同的值我想要正确的值，如 5445,8545,1245 它来自列表

Answer 1

首先，您需要将数据定义为这样的列表：

List data = [];

然后像这样使用它：

myMethod(){
    for (var i = 0; i < transactionLists.length; i++) {
      if (monthName[monthIndex] == "July") {
        data.add(transactionLists[i].july.toString());//<--- change this
         print(data);
      } else if (monthName[monthIndex] == "August") {
        data.add(transactionLists[i].august.toString());//<--- change this
      } else if (monthName[monthIndex] == "September") {
        data.add(transactionLists[i].september.toString());//<--- change this
      } else if (monthName[monthIndex] == "October") {
        data.add(transactionLists[i].october.toString());//<--- change this
      } //.... up to all 12 months
     }
     return ListView.builder(
      padding: EdgeInsets.zero,
      shrinkWrap: true,
      physics: const NeverScrollableScrollPhysics(),
      itemCount: data.length,//<--- change this
      itemBuilder: (context, childIndex) {
         return Text(
            data[childIndex],//<--- change this
           );
      }
}