android:关闭光标后我们需要关闭Db吗？

Question

从SQLiteCursor的源代码(堆栈跟踪):

at android.database.sqlite.SQLiteDatabase.dbclose(Native Method)
at android.database.sqlite.SQLiteDatabase.onAllReferencesReleased(SQLiteDatabase.java:325)
at android.database.sqlite.SQLiteClosable.releaseReference(SQLiteClosable.java:45)
at android.database.sqlite.SQLiteProgram.onAllReferencesReleased(SQLiteProgram.java:119)
at android.database.sqlite.SQLiteClosable.releaseReference(SQLiteClosable.java:45)
at android.database.sqlite.SQLiteProgram.close(SQLiteProgram.java:296)
at android.database.sqlite.SQLiteQuery.close(SQLiteQuery.java:136)
at android.database.sqlite.SQLiteCursor.close(SQLiteCursor.java:506)

这是否意味着,关闭最后一个光标也将关闭数据库.我们不需要明确地关闭它,就像在这段代码中一样:

    SQLiteDatabase rdb = db.getReadableDatabase();
    Cursor resultCursor = null;
    String patternQuery = SQLiteQueryBuilder.buildQueryString(true, "Store", columns, where, null, null, null, null);

    try
    {
        resultCursor = rdb.rawQuery(patternQuery, null);


        resultCursor.moveToFirst();
        if (resultCursor.getCount() > 0)
        {
            while (!resultCursor.isAfterLast())
            {
                result.add(resultCursor.getString(0));
                resultCursor.moveToNext();
            }
        }
    }
    catch (Exception e)
    {
        Log.d("DB", "Caught an exception while getting pattern based results: " + e);
    }
    finally
    {
        if (resultCursor != null)
        {
            resultCursor.close();
        }
        if (rdb.isOpen())
        {
            rdb.close();
        }
    }

所以在这里,我们不需要关闭rdb？

注意:游标对象保留对数据库的引用,因此它在每个查询上都获得相同的锁定.因此'SQLiteDatabse.dbclose'有效地关闭了同一个数据库.

Answer 1

你确实需要关闭它。在您显式关闭数据库并且所有活动游标都已关闭之前，数据库不会关闭。