CursorIndexOutOfBoundsException:请求索引2，大小为2。如何解决？

Question

查询SQLite数据库时，只显示2行。有可能修复这个错误吗？

Cursor cursor = database.rawQuery("SELECT * FROM Category", null);
            cursor.moveToFirst();
            for (int i = 0; i < 10; i++) {
                categoryList.add(new Category(cursor.getInt(0), cursor.getString(1)));
                cursor.moveToNext();
            }
            cursor.close();
            database.close();

错误：

Process: com.triangle.learningenglish, PID: 30477
    java.lang.RuntimeException: Unable to start activity ComponentInfo{com.triangle.learningenglish/com.triangle.learningenglish.Select.SelectCategory}: android.database.CursorIndexOutOfBoundsException: Index 2 requested, with a size of 2

Answer 1

造成此错误的原因是您没有检查游标是否为空。您只需遍历for循环并检索可能有或没有值的结果。

我想这行代码解决了你的问题

Cursor cursor = database.rawQuery("SELECT * FROM Category", null);
            
int numberOfRows = cursor.getCount();
int counter = 1;
cursor.moveToFirst();
        while(numberOfRows !=0 && counter <= numberOfRows){
             categoryList.add(new Category(cursor.getInt(0), cursor.getString(1)));
             counter++;
             cursor.moveToNext();
            }
            cursor.close();
            database.close();