Android SQLite关闭异常 [英] Android SQLite closed exception

问题描述

我没有扎实的同步背景.我认为使用 synchronized 方法可以解决此问题.但是有人可以帮助我解决此问题吗?代码如下:

I have no solid background of synchronization. I think this issue will be fixed when I use synchronized method. But can anyone help me to fix this issue? Code is below:

public HashMap<String, FriendInfo> getAllRecordsInList_HashMap() {

        MySQLiteHelper dbHelper = MySQLiteHelper.getInstance(mActivity);
        HashMap<String, FriendInfo> list_map = new HashMap<String, FriendInfo>();

        SQLiteDatabase db = dbHelper.getReadableDatabase();
        // Cursor cursor = db.rawQuery("SELECT * from " +
        // dbHelper.tbl_friendlist, new String[] {});
        String[] cols = { dbHelper.id, dbHelper.name, dbHelper.picture, dbHelper.birthday, dbHelper.livein, dbHelper.gender, dbHelper.is_online, dbHelper.is_vip };
        Cursor cursor = db.query(dbHelper.tbl_friendlist, cols, null, null, null, null, dbHelper.name);

        if (cursor != null && cursor.getCount() > 0) {

            // some code here....
        }
        cursor.close();
        return list_map;
    }

不同的线程可以调用此方法getAllRecordsInList_HashMap().如果我使用同步方法，请告知如何解决此问题.会解决吗?

Different threads can call this method getAllRecordsInList_HashMap(). Please advise how to fix this issue if I make synchronized method. Will it be fixed?

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) 
at android.database.sqlite.SQLiteSession.executeForCursorWindow(SQLiteSession.java:834) 
at android.database.sqlite.SQLiteQuery.fillWindow(SQLiteQuery.java:62) 
at android.database.sqlite.SQLiteCursor.fillWindow(SQLiteCursor.java:143) 
at android.database.sqlite.SQLiteCursor.getCount(SQLiteCursor.java:133) 
at com.platinumapps.friendlist.BLL_Friendlist.getAllRecordsInList_HashMap(BLL_Friendlist.java:290) 
at com.platinumapps.activities.Messages_Activity.addViewTOLayout(Messages_Activity.java:753) 
at com.platinumapps.activities.Messages_Activity.access$3(Messages_Activity.java:744) 
at com.platinumapps.activities.Messages_Activity$1$3.run(Messages_Activity.java:141) 
at ndroid.app.Activity.runOnUiThread(Activity.java:4644) 
at com.platinumapps.activities.Messages_Activity$1.onReceive(Messages_Activity.java:136) 
at android.app.LoadedApk$ReceiverDispatcher$Args.run(LoadedApk.java:758) 
at android.os.Handler.handleCallback(Handler.java:725) 
at android.os.Handler.dispatchMessage(Handler.java:92) 
at android.os.Looper.loop(Looper.java:137) 
at android.app.ActivityThread.main(ActivityThread.java:5039) 
at java.lang.reflect.Method.invokeNative(Native Method) 
at java.lang.reflect.Method.invoke(Method.java:511) 
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560) 
at dalvik.system.NativeStart.main(Native Method)

推荐答案

根据 Dianne Hackborn (Android框架工程师)，无需在内容提供商中关闭数据库

According to Dianne Hackborn (Android framework engineer) there is no need to close the database in a content provider

创建内容托管服务商时会创建一个内容提供商， 并在进程运行期间一直存在，因此不需要关闭数据库，因为当进程被杀死时，内核将清理进程的资源，因此数据库将关闭.

A content provider is created when its hosting process is created, and remains around for as long as the process does, so there is no need to close the database it will get closed as part of the kernel cleaning up the process's resources when the process is killed.

因此无需关闭数据库.它将在不需要时自动关闭.

So there is no need to close the database . it will automatically close when it is not needed.

这篇关于Android SQLite关闭异常的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！