how to break while loop using some conditional check?

[SHUBHAM SINGH RAO]

Hi
I am using SQLite database to fetch the data in Qt and then I am printing that data simultaneosly.
Kindly go through the process

(e.g.

   while(studentList.next())
                 {  studentList("SELECT Name, address FROM class  WHERE Roll No = some variable;
                  Name=studentList.value(0).toString();   
                  address=studentList.value(1).toString();   


 //********   simultaneously I am printing this data (in a string) through GPIO pins by setting them HIGH accordingly.....    ******  //
                                  

{


      ------  PRINTING MODULE ------

 }
                 }  

During printing, GUI goes in a hang state .....
Now I want to break this printing in between as per my wish!
Any way to do it!

[SGaist]

Hi,

Depending on how you do that printing and more specifically the time it takes, you should rather offload the work to a secondary thread.

[aha_1980]

If the time the printing module takes is rather short, it may already be enough to break the loop and put the loops body in a QTimers slot that you call regularly in short intervalls.

So in the time between the timers slots Qt has time to execute it's event loop.

[SHUBHAM SINGH RAO]

@SGaist Right now I m in the learning stage of threading..so a bit difficult for me to apply it directly
Could u plz quote an example which can be referred?

[VRonin]

See "Staying Responsive During Intensive Processing" page 171 (189 of the pdf) of C++ GUI Programming with Qt 4

[SHUBHAM SINGH RAO]

This post is deleted!

[SGaist]

Your loop blocks the event loop so it can't process anything.