相关疑难解决方法(0)

在Android应用程序中对SQLite数据库执行查询时,最佳做法是什么？

从AsyncTask的doInBackground运行插入,删除和选择查询是否安全？或者我应该使用UI线程？我认为数据库查询可能"很重",不应该使用UI线程,因为它可以锁定应用程序 - 导致应用程序无响应(ANR).

如果我有几个AsyncTasks,他们应该共享一个连接还是应该分别打开一个连接？

这些方案是否有最佳实践？

我有一个包含一些表的数据库.我想使用多个线程更新表.我将在所有线程中使用相同的SQLiteDatabase实例.

请建议这种方法是否正确.Sqlite数据库线程安全吗？两个不同的线程可以同时为不同的值集更新同一个表.

我们AsyncTasks用来访问数据库表和游标.

不幸的是,我们偶尔会看到有关数据库被锁定的例外情况.

E/SQLiteOpenHelper(15963): Couldn't open iviewnews.db for writing (will try read-only):
E/SQLiteOpenHelper(15963): android.database.sqlite.SQLiteException: database is locked
E/SQLiteOpenHelper(15963):  at     android.database.sqlite.SQLiteDatabase.native_setLocale(Native Method)
E/SQLiteOpenHelper(15963):  at     android.database.sqlite.SQLiteDatabase.setLocale(SQLiteDatabase.java:1637)
E/SQLiteOpenHelper(15963):  at     android.database.sqlite.SQLiteDatabase.<init>(SQLiteDatabase.java:1587)
E/SQLiteOpenHelper(15963):  at android.database.sqlite.SQLiteDatabase.openDatabase(SQLiteDatabase.java:638)
E/SQLiteOpenHelper(15963):  at android.database.sqlite.SQLiteDatabase.openOrCreateDatabase(SQLiteDatabase.java:659)
E/SQLiteOpenHelper(15963):  at android.database.sqlite.SQLiteDatabase.openOrCreateDatabase(SQLiteDatabase.java:652)
E/SQLiteOpenHelper(15963):  at android.app.ApplicationContext.openOrCreateDatabase(ApplicationContext.java:482)
E/SQLiteOpenHelper(15963):  at android.content.ContextWrapper.openOrCreateDatabase(ContextWrapper.java:193)
E/SQLiteOpenHelper(15963):  at android.database.sqlite.SQLiteOpenHelper.getWritableDatabase(SQLiteOpenHelper.java:98)
E/SQLiteOpenHelper(15963):  at android.database.sqlite.SQLiteOpenHelper.getReadableDatabase(SQLiteOpenHelper.java:158)
E/SQLiteOpenHelper(15963):  at com.iview.android.widget.IViewNewsTopStoryWidget.initData(IViewNewsTopStoryWidget.java:73)
E/SQLiteOpenHelper(15963):  at com.iview.android.widget.IViewNewsTopStoryWidget.updateNewsWidgets(IViewNewsTopStoryWidget.java:121)
E/SQLiteOpenHelper(15963):  at com.iview.android.async.GetNewsTask.doInBackground(GetNewsTask.java:338)
E/SQLiteOpenHelper(15963):  at com.iview.android.async.GetNewsTask.doInBackground(GetNewsTask.java:1)
E/SQLiteOpenHelper(15963):  at android.os.AsyncTask$2.call(AsyncTask.java:185)
E/SQLiteOpenHelper(15963):  at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:256)
E/SQLiteOpenHelper(15963):  at java.util.concurrent.FutureTask.run(FutureTask.java:122)
E/SQLiteOpenHelper(15963):  at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:648)
E/SQLiteOpenHelper(15963):  at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:673)
E/SQLiteOpenHelper(15963):  at java.lang.Thread.run(Thread.java:1060)

有没有人有一个代码的一般例子,它从一个读取的不同线程写入数据库,我们如何确保线程安全. …