[Qt-interest] [MVC] Can signals connect / disconnect dynamically to reduce overhead on GUI thread?

[Ed Sutton]

Thank you Thomas.  Thank you Pritam.

Each item is a network device.  My concern was many signals connected to a few slots.  

1 - If one item is selected in the treeview, the device being viewed will  generates a continuos real-time stream of perhaps 10 signals per second of various parameters such as temperature, current, and voltage.  
2 - If a group of 20 items is selected, in treeview , then 20*10 signals per second will be sent to update temperature, voltage, and current in a listview.  For better GUI performance I suppose I might need to add a signalRatePerSecond property to throttle back the signals per second when many items are selected.

Anyway, thank you both.  I think I just need to dive into the MVC examples and figure it out.

-Ed


On Nov 29, 2011, at 1:50 AM, Thomas McGuire wrote:

> Hi,
> 
> On Tuesday 29 November 2011 06:05:25 Ed Sutton wrote:
>> I am seeking design advice.
>> 
>> My GUI is similar to the Windows File or Nautilus file explorer with a
>> split windows interface; the left-pane selects the item to browse and the
>> right-pane displays views of static and dynamic data.  There could be
>> hundreds of network devices in the left-pane tree view.  My concern is the
>> overhead of all these signal callbacks will overwhelm the GUI performance
>> if connected to all of them.  Can signals be connected to and disconnected
>> dynamically to reduce the callback overhead on the GUI thread?
>> 
>> [..]
>> 
>> I am thinking I should use the Model View Controller (MVC) pattern.  I am
>> just not sure if the Qt disconnect is meant to be used this way?
> 
> Using the model view framework in Qt is a good idea. This will solve your 
> problem automatically, since there is just a single signal when an item is 
> clicked, in your case that would be QTreeView::clicked(const QModelIndex &). 
> So there is one single signal for all items, so no overhead related to too 
> many connections.
> 
> Regards,
> Thomas
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-Ed