关闭数据库是否必不可少？-Isitessentialtoclosethedatabase?

10  

If you don't close the database connections, they'll cause memory leaks over time.

如果不关闭数据库连接，它们将导致内存泄漏。

The Notepad example does use startManagingCursor, but you still need to explicitly close the db connection. Run the Notepad example as-is and edit several notes in succession, you'll see that it starts throwing Warnings and Errors in LogCat. (In larger applications, you'll also start to see Memory Leak Detection warnings.)

记事本示例使用startManagingCursor，但您仍需要显式关闭数据库连接。按原样运行记事本示例并连续编辑几个注释，您将看到它开始在LogCat中抛出警告和错误。 （在较大的应用程序中，您也将开始看到内存泄漏检测警告。）

W/SQLiteCompiledSql(  302): Releasing statement in a finalizer. Please ensure that you explicitly call close() on your cursor: INSERT INTO notes(body, title) VALUES(?, ?);
W/SQLiteCompiledSql(  302): android.database.sqlite.DatabaseObjectNotClosedException: Application did not close the cursor or database object that was opened here
W/SQLiteCompiledSql(  302):     at android.database.sqlite.SQLiteCompiledSql.(SQLiteCompiledSql.java:62)
...
W/SQLiteCompiledSql(  302):     at dalvik.system.NativeStart.main(Native Method)
E/Database(  302): close() was never explicitly called on database '/data/data/com.android.demo.notepad3/databases/data' 
E/Database(  302): android.database.sqlite.DatabaseObjectNotClosedException: Application did not close the cursor or database object that was opened here
E/Database(  302):  at android.database.sqlite.SQLiteDatabase.(SQLiteDatabase.java:1810)
...
E/Database(  302):  at dalvik.system.NativeStart.main(Native Method)

You mentioned that closing it in onDestroy() "leaves vulnerabilities" in any non-UI threads that are still running. If you're using AsyncTask, you can check the status of of these threads using getStatus on your tasks.

你提到在onDestroy（）中关闭它会在任何仍在运行的非UI线程中“留下漏洞”。如果您正在使用AsyncTask，则可以使用任务上的getStatus检查这些线程的状态。

if ( myAsyncTask.getStatus() == AsyncTask.Status.FINISHED ){
    mDbHelper.close();
}

Then close the connection in the onPostExecute method of your AsyncTask.

然后在AsyncTask的onPostExecute方法中关闭连接。

Hope that helps...

希望有帮助......

0  

You should close it.

你应该关闭它。

The notepad example should be using Activity's startManagingCursor.

记事本示例应该使用Activity的startManagingCursor。