4

我已经阅读了很多关于在 android 中使用标准 SQLiteDatabase 的内容,似乎最好的方法是保留一个 SQLiteOpenHelper 实例,并且永远不要关闭返回的 SQLiteDatabase 对象,也不要关闭 SQLiteOpenHelper。问题是这些准则在使用 SQCipher 加密库时是否有效?似乎 SQCipher 包中 SQLiteOpenHelper 的 close() 方法不是空的,并且确实释放了一些东西。从不调用此方法是否安全?

下面是来自 Github ( http://goo.gl/u4L0C )的 SQLiteDatabase.close() 方法的实际代码:

public void close() {

    if (!isOpen()) {
        return; // already closed
    }
    lock();
    try {
        closeClosable();
        // close this database instance - regardless of its reference count value
        onAllReferencesReleased();
    } finally {
        unlock();
    }
}

private void closeClosable() {
    /* deallocate all compiled sql statement objects from mCompiledQueries cache.
     * this should be done before de-referencing all {@link SQLiteClosable} objects
     * from this database object because calling
     * {@link SQLiteClosable#onAllReferencesReleasedFromContainer()} could cause the database
     * to be closed. sqlite doesn't let a database close if there are
     * any unfinalized statements - such as the compiled-sql objects in mCompiledQueries.
     */
    deallocCachedSqlStatements();

    Iterator<Map.Entry<SQLiteClosable, Object>> iter = mPrograms.entrySet().iterator();
    while (iter.hasNext()) {
        Map.Entry<SQLiteClosable, Object> entry = iter.next();
        SQLiteClosable program = entry.getKey();
        if (program != null) {
            program.onAllReferencesReleasedFromContainer();
        }
    }
}
4

0 回答 0