android IllegalStateException，数据库已经关闭

Question

我正在使用 SimpleCursorAdapter 和数据库表来填充列表。该列表已填充，我可以单击列表项以打开所需的项目(这将启动一个新 Activity )。问题是当我按后退键时，出现以下错误。

IllegalStateException:数据库已经关闭。

我的代码如下:

public class populatingLectures extends ListActivity{

private static String[] FROM = {SUBJECT, TOPIC, LECTURENUMBER, DATE };
private static int[] TO = {R.id.subject, R.id.topic,
        R.id.lecturenumber, R.id.date };
private static String[] data = { SUBJECT, TOPIC, LECTURENUMBER, _DATA };
private static String ORDER_BY = DATE + " DESC";
private SoftCopyDatabase lectures;  
String gotId;


@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    SoftCopyDatabase lectures = new SoftCopyDatabase(this);
    try {
        Cursor cursor = getLectures();
        showLectures(cursor);
    } finally {
        lectures.close();
    }
}

public void onStart() {
    super.onStart();
    lectures = new SoftCopyDatabase(this);
    try {
        Cursor cursor = getLectures();
        showLectures(cursor);
    } finally {
        lectures.close();
    }
}

private Cursor getLectures() {

    SQLiteDatabase db = lectures.getReadableDatabase();

    Cursor cursor = db.query(TABLE_NAME,null, "subject=?", new String[] {OpenClick.subjectName}, null, null,
            ORDER_BY);
    startManagingCursor(cursor);
    return cursor;
}


private void showLectures(Cursor cursor) {

    SimpleCursorAdapter adapter = new SimpleCursorAdapter(this,
            R.layout.item_lectures, cursor, FROM, TO);
    setListAdapter(adapter);
}

private Cursor getFileName(String ID) {

    SQLiteDatabase db = lectures.getReadableDatabase();
    Cursor cursor = db.query(TABLE_NAME, data, "_ID=?",
            new String[] { ID }, null, null, null);
    startManagingCursor(cursor);
    return cursor;
}


@Override
protected void onListItemClick(ListView listView, View view, int position,
        long id) {
    super.onListItemClick(listView, view, position, id);

             //...CODE TO START NEW ACTIVITY

    }
}


}

请告诉我我做错了什么。因为我没有在任何地方显式关闭数据库。

问候，瓦内亚·伊克巴尔。

Answer 1

finally
{       
 lectures.close();
}

我认为这一行给出了异常，所以把它放在 onDestroy() 中。