[Qt-interest] Asynchronous quitting of Symbian application

[prabodh.depala at nokia.com]

Hi,

You may have to use, CActiveSchedulerWait, a Symbian concept to fix this:

#include <e32base.h> 
Link against: euser_v5.lib 
Link against: euser_v6.lib 
Link against: euser_v6k.lib 

//construct it
CActiveSchedulerWait* mSchedulerWait = new CActiveSchedulerWait();

// Signal middleware to quit as received close event from the taskmanager
//emit something...
mSchedulerWait->Start(); //start the wait loop

//Slot to get a signal from the middleware to notify that it has shut down 
MyUI::mySlot()
mSchedulerWait-> AsyncStop(); //Stop the wait loop

//destruct it
delete mSchedulerWait;


Regards,
Prabodh



-----Original Message-----
From: qt-interest-bounces+prabodh.depala=nokia.com at qt.nokia.com [mailto:qt-interest-bounces+prabodh.depala=nokia.com at qt.nokia.com] On Behalf Of ext Bo Elmgreen
Sent: 28 September 2011 10:55
To: pritam_ghanghas at infosys.com
Cc: qt-interest at qt.nokia.com
Subject: Re: [Qt-interest] Asynchronous quitting of Symbian application

Hi all,

Well, I have now tried out different suggestions, but unfortunately none of them worked for me. I tried to listen to the QWidget::closeEvent(), but as far as I have been able to find out, this one is only called if the user presses the default exit (right) soft key. As I have set up my own action for the right soft key, closeEvent() is not called. And when the application is closed from the task manager, closeEvent() is not supposed to be called at all, as the "UI has already been torn down by the UI framework", see: 
http://qt.gitorious.org/qt-labs/nacl/commit/8aec69a/diffs.

Another suggestion was to use the Session Management framework, but as far as I can determine, it is not enabled by default on the Symbian platform. At least, if you override the appropriate methods in your derived QApplication, they are not called when closing the application.

There was a suggestion in the qt.gitorious link above to re-implement the platform specific event filter, in order to catch the EEikCmdExit command. If I find time, I will give that a try.

Cheers,
Bo

On 27/09/2011 16:49, Bo Elmgreen wrote:
> Hi Pritam,
>
> That indeed looks like what I was searching for. Thanks!
>
> BR,
> Bo
>
> On 27/09/2011 16:22, Pritam Ghanghas wrote:
>> On Tue, 2011-09-27 at 17:16 +0530, Bo Elmgreen wrote:
>>> Hi all,
>>>
>>> I am developing an application for Symbian and I have come across a 
>>> problem, where I could use some advice :-)
>>>
>>> My application is divided in two: A (widget-based) UI part and some 
>>> "middleware" components, that run in their own (Q)Thread, that 
>>> communicate with some servers over a data connection. The 
>>> communication between the UI and the middleware is done via signals and slots.
>>>
>>> The problem arises, when it is time to quit the application in a 
>>> special situation. If the user selects the "Exit" option in the UI, 
>>> the UI components can dispose of the middleware and exit the 
>>> application when the middleware has signalled that this has 
>>> completed. But if the application is closed from the task manager, 
>>> the application will not know what is happening before either 1) the 
>>> main window destructor is called or 2) it listens to the aboutToQuit 
>>> signal. But in both cases it appears as though the application has 
>>> to quit synchronously, leaving me with the problem that I cannot 
>>> wait for the middleware to exit properly :-(
>>>
>>> I guess that I am not the only one having this kind of design, so 
>>> how is this situation "normally" handled?
>> Look at documentation of QWidget::closeEvent().
>> handle this event and quit when you are ready.
>>
>>> Thanks in advance!
>>>
>>> Best Regards,
>>> Bo
>>>
>>> _______________________________________________
>>> Qt-interest mailing list
>>> Qt-interest at qt.nokia.com
>>> http://lists.qt.nokia.com/mailman/listinfo/qt-interest
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