小编use*_*181的帖子

我在我的项目中发现Android上SQLiteDatabase实现中的close()函数在运行打开数据库,插入数据然后关闭数据库的多个线程时抛出NullPointerException.除非我允许每个线程在插入数据库后关闭(),否则一切都会顺利运行.

以下是其中一个写入线程可能看起来像的示例

        ContentValues values = new ContentValues();
        values.put(CallDetailsStorageConstants.COLUMN_NAME_REMOTE_NAME_IDX, (String) "");
        values.put(CallDetailsStorageConstants.COLUMN_NAME_REMOTE_MEETINGID_IDX, (String) "");

        CalculonDatabase callDetailsOpenHelper = CalculonDatabase.getInstance(mContext);
        SQLiteDatabase dbw = callDetailsOpenHelper.getWritableDatabase();

        long rowid = 0;
        try {
            rowid = dbw.insertWithOnConflict(CallDetailsTable.CALL_DETAILS_TABLE_NAME, null, values, SQLiteDatabase.CONFLICT_REPLACE);
        } catch (SQLiteConstraintException e) {
            e.printStackTrace();
        } finally {
            dbw.close();
        }

你可以看到最后调用close().运行多个线程时,我得到此异常.

11-03 03:39:26.128: E/AndroidRuntime(977): FATAL EXCEPTION: Thread-17
11-03 03:39:26.128: E/AndroidRuntime(977): java.lang.NullPointerException
11-03 03:39:26.128: E/AndroidRuntime(977):  at     android.database.sqlite.SQLiteStatement.releaseAndUnlock(SQLiteStatement.java:283)
11-03 03:39:26.128: E/AndroidRuntime(977):  at android.database.sqlite.SQLiteStatement.executeUpdateDelete(SQLiteStatement.java:96)
11-03 03:39:26.128: E/AndroidRuntime(977):  at android.database.sqlite.SQLiteDatabase.executeSql(SQLiteDatabase.java:1933)
11-03 03:39:26.128: E/AndroidRuntime(977):  at android.database.sqlite.SQLiteDatabase.execSQL(SQLiteDatabase.java:1864)
11-03 03:39:26.128: E/AndroidRuntime(977):  at android.database.sqlite.SQLiteDatabase.beginTransaction(SQLiteDatabase.java:636) …