Android的：不能执行此操作，因为连接池已关闭 [英] Android: Cannot perform this operation because the connection pool has been closed

问题描述

我读通过计算器关于这个问题，我还没有找到一个解决方案。我注意到，有时，我的应用程序引发此错误：

I was reading through stackoverflow about this question and I still haven't found a solution. I notice that sometimes, my app throws this error:

   java.lang.IllegalStateException: Cannot perform this operation because the connection pool has been closed.
        at android.database.sqlite.SQLiteConnectionPool.throwIfClosedLocked(SQLiteConnectionPool.java:962)
        at android.database.sqlite.SQLiteConnectionPool.waitForConnection(SQLiteConnectionPool.java:599)
        at android.database.sqlite.SQLiteConnectionPool.acquireConnection(SQLiteConnectionPool.java:348)
        at android.database.sqlite.SQLiteSession.acquireConnection(SQLiteSession.java:894)
        ...

我有一个使用这种方法来获得它的一个实例名为DatabaseHelper.java文件：

I have a file called DatabaseHelper.java using this approach to get an instance of it:

public static DatabaseHelper getInstance(Context context) {
    if (mInstance == null) {
        mInstance = new DatabaseHelper(context.getApplicationContext());
    }
    return mInstance;
}

然后，我有像这样的方法（它在该行cursor.moveToFirst（）与该错误崩溃）。它几乎从来没有崩溃，但有时它。

Then I have methods like this one (that it crashed in the line cursor.moveToFirst() with that error). It almost never crashes but sometimes it does.

public Profile getProfile(long id) {
    SQLiteDatabase db = this.getReadableDatabase();

    String selectQuery = "SELECT * FROM " + TABLE_PROFILES + " WHERE " + KEY_PROFILES_ID + " = " + id;
    Cursor cursor = db.rawQuery(selectQuery, null);

    // looping through all rows and adding to list
    Profile profile = new Profile();
    if (cursor.moveToFirst()) {
        doWhatEver();
    }
    cursor.close();
    db.close();

    return profile;
}

所以这是它，在所有的方法我用的：

So that's it, in all the methods I use:

SQLiteDatabase db = this.getReadableDatabase(); (or Writable)

然后我关闭游标和DB。在这种情况下，该错误得到扔在线路：

And then I close the cursor and the db. In this case, the error got throw in the line:

cursor.moveToFirst();

我不明白为什么错误说，如果我是（）之前调用this.getReadableDatabase分贝关闭。请大家支持！谢谢：）

I do not see why the error says the db is closed if I am calling this.getReadableDatabase() before. Please support! Thank you :)

推荐答案

删除

db.close();

如果您尝试关闭数据库陆续投产，它会给你的例外。

If you try another operation after closing the database, it will give you that exception.

的<一个href="http://developer.android.com/reference/android/database/sqlite/SQLiteClosable.html#close()">documentation说：

发布一个参考对象，关闭对象...

此外，检查出 的Andr​​oid平米精简版封闭异常

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