java - 如何解决IndexOutOfBoundsException : Invalid index 1,大小为1？

Question

这个问题已经有答案了:

What causes a java.lang.ArrayIndexOutOfBoundsException and how do I prevent it? (25 个回答)

已关闭 7 年前。

我刚刚收到 java.lang.IndexOutOfBoundsException: 但无法理解其原因。基本上，我将 sqlite 表的记录集成到 ListView 中。这是我从表中获取记录的 SQL 查询。

public ArrayList<Integer> getRecordsCount(int no) {

    ArrayList<Integer> count = new ArrayList<>();

    Cursor c = database.rawQuery(
            "select count(*) as TotalCount, tDate, " +
                    "strftime('%d', tDate) as DayPart, " +
                    "strftime('%m', tDate) as MonthPart, " +
                    "strftime('%Y', tDate) as YearPart " +
                    "from library " +
                    "where type = '" + no + "' " +
                    "group by MonthPart, YearPart", null);

    while (c.moveToNext()) {
        count.add(c.getInt(0));
    }

    return count;
}

这是我检索该数据的方法:-

public void setDataInList(int no) {

    if (no == 0) {

        ArrayList<Integer> count = helper.getRecordsCount(1);

        mainGetLibraryModels.clear();
        MainLibraryModelWS modelWS = helper.getAllRecordsMonthWise2(no);
        for (int i = 0; i < modelWS.getRecords().size(); i++) {

            WSLibraryModel model = new WSLibraryModel();
            model.setAmount(modelWS.getRecords().get(i).getAmount());
            model.setTotalCount("" + count.get(i));
            model.setYearPart(modelWS.getRecords().get(i).getYearPart());
            model.setMonthPart(modelWS.getRecords().get(i).getMonthPart());

            mainGetLibraryModels.add(model);

        }
        adapter.notifyDataSetChanged();

    } else if (no == 1) {

        ArrayList<Integer> count = helper.getRecordsCount(2);

        mainGetLibraryModels.clear();
        MainLibraryModelWS modelWS = helper.getAllRecordsMonthWise2(no);
        for (int i = 0; i < modelWS.getRecords().size(); i++) {

            WSLibraryModel model = new WSLibraryModel();
            model.setAmount(modelWS.getRecords().get(i).getAmount());
            model.setTotalCount("" + count.get(i));
            model.setYearPart(modelWS.getRecords().get(i).getYearPart());
            model.setMonthPart(modelWS.getRecords().get(i).getMonthPart());

            mainGetLibraryModels.add(model);
        }
        adapter.notifyDataSetChanged();

    } else {

        mainGetLibraryModels.clear();
        MainLibraryModelWS modelWS = helper.getAllRecordsMonthWise2(no);
        for (int i = 0; i < modelWS.getRecords().size(); i++) {

            WSLibraryModel model = new WSLibraryModel();
            model.setAmount(modelWS.getRecords().get(i).getAmount());
            model.setTotalCount(" - ");
            model.setYearPart(modelWS.getRecords().get(i).getYearPart());
            model.setMonthPart(modelWS.getRecords().get(i).getMonthPart());

            mainGetLibraryModels.add(model);

        }
        adapter.notifyDataSetChanged();

    }
 }

但是，当我运行这段代码时，它给了我这个错误？

FATAL EXCEPTION: main Process: com.teezom, PID: 14168
java.lang.IndexOutOfBoundsException: Invalid index 1, size is 1
    at java.util.ArrayList.throwIndexOutOfBoundsException(ArrayList.java:255)
    at java.util.ArrayList.get(ArrayList.java:308)

Answer 1

首先使用 switch 而不是 if-else 分支，因为我从查询中看到的结果将以数组形式给出固定数量的结果(switch 是更高效并提高可读性)。

public void setDataInList(int no) {  //just a suggestion not a answer

  switch (no){
     case 0 :   
          //Your Code as you specified in your code context.
           break;
     case 1 :
          //Your Code as you specified in your code context.

          break;
     case 2 :
          //Your Code as you specified in your code context.

         break;
    default :
         break;
   }

如果您看到 Exception StackTrace，那么现在就来解决您的问题，并在轻松获得解决方案后调试应用程序。

this is what your stacktrace says--

java.lang.IndexOutOfBoundsException: Invalid index 1, size is 1

希望您知道这个流行的异常IndexOutOfBoundsException仅在您尝试访问数组中不存在的任何数组索引时出现。

现在您的错误消息清楚地表明您的Array大小是one。这意味着您的数组只能访问索引零 (0)。

所以，请调试您的代码并尝试找出哪一行代码实际上生成了异常