android.database.CursorWindowAllocationException：2048 KB光标窗口配置即使在关闭游标后失败 [英] android.database.CursorWindowAllocationException: Cursor window allocation of 2048 kb failed even after closing cursor

问题描述

有对SO有关CursorWindowAllocatoinException许多问题：

There are many questions on SO about CursorWindowAllocatoinException:

• <一个href="http://stackoverflow.com/questions/11340257/sqlite-android-database-cursor-window-allocation-of-2048-kb-failed">SQLite 2048 KB Android的数据库光标窗口分配失败
• 无法分配CursorWindow
• 内存的分配游标时
• <一个href="http://stackoverflow.com/questions/12029437/android-mysqlite-cursorwindowallocationexception-crash">Android MySQLite CursorWindowAllocationException崩溃

• SQLite Android Database Cursor window allocation of 2048 kb failed
• Could not allocate CursorWindow
• Out of Memory when allocating cursors
• Android MySQLite CursorWindowAllocationException crash

所有这些表明光标在使用后必须封闭。但是，这并没有解决我的问题。这是我的code：

All of them suggest that cursor must be closed after use. But that did not resolve my problem. Here is my code:

String query = "select serial from tbl1 union select serial from tbl2 union select serial from tbl3";
    SQLiteDatabase db = null;
    Cursor cur = null;
    try {
        SettingsDatabaseHelper dal = new SettingsDatabaseHelper(
                c);
        db = dal.getReadableDatabase();
        cur = db.rawQuery(query, null);
        int numRows = cur.getCount();
        if (numRows > 0) {
            cur.moveToFirst();

            int serialIdx = cur.getColumnIndexOrThrow("serial");
            for (boolean hasItem = cur.moveToFirst(); hasItem; hasItem = cur
                    .moveToNext()) {

                String serial = cur.getString(serialIdx);
                if (Validator.getInstance().isValidSerial(serial))
                    serials.add(serial);

            }
        }
    } finally {
        if (cur != null)
            cur.close();

        if (db != null)
            db.close();
    }

我跑这个方法每隔几秒钟。半个多小时后，我得到 CursorWindowAllocationException 在 INT = numRows行cur.getCount（）; ，然后我的服务停止。

I run this method every few seconds. After half an hour, I get CursorWindowAllocationException in int numRows=cur.getCount(); and then my service stops.

由于我关闭游标，有可能是与我的助手类的问题。这里是code：

Since I am closing the cursor, there may be a problem with my Helper class. Here is the code:

public class SettingsDatabaseHelper extends SQLiteOpenHelper {

    private static final String DATABASE_NAME = "mydb.db";
    private static final int DATABASE_VERSION = 1;


    private static final String TBL_CREATE="create table...";



    public SettingsDatabaseHelper(Context context) {
        super(context, DATABASE_NAME, null, DATABASE_VERSION);
    }

    @Override
    public void onCreate(SQLiteDatabase database) {
        database.execSQL(TBL_CREATE);
    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        onCreate(db);
    }
}

我怎样才能prevent此异常被抛出？

How can I prevent this exception from being thrown?

推荐答案

我是从一个服务查询数据库。当我从一个活动做到了，这个问题不会再发生了。

I was querying the database from a service. When I did it from an activity, the problem never occurred again.

除了查询，我从串口读取相同的服务范围内。也许这造成了问题。然而，当我使用的服务的活动，而不是，这个问题永远不会再次发生。

Alongside querying, I was reading from the serial port within the same service. Maybe that caused the problem. However, when I used an activity instead of the service, the problem never happened again.

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