Access violation error in QtConcurrent updating QLabel
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hello i have this 'access violation reading..." error in QtConcurrent thread when am i terminating my application. My thread is updating some status in QLabel. it seems like when i exit my application QLabel object is being destroyed and my thread is working on it. how can i resolve it ? here is my source
@
void Sparsh::connectCam()
{
QString str[]={"Connecting.","Connecting..","Connecting..."};
unsigned int i=1;while(!mycam.Connect(FIRST_AVAILABLE))
{
if(ui.lblStatus) // i tried this but no help :(
ui.lblStatus->setText(str[i%3]);Sleep(1000);
i++;
}camconnected=true;
ui.lblStatus->setText("Device Connected...!");
}
@
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Hi,
Qt's GUI classes are not thread-safe. You can only update them in the main thread.
If you want to trigger an update from a secondary thread, your secondary thread must invoke a slot in the main thread to update your QLabel.
- Use "QMetaObject::invokeMethod()":http://qt-project.org/doc/qt-5/qmetaobject.html#invokeMethod with a Queued Connection, OR
- Emit a signal to invoke the slot.
