QLineEdit update before external method

[Ishtar]

Greetings All

I have something like the following in my project.




MainRoutine doStuff;

QLineEdit test = new QLineEdit();
test.setText("Updating...");

doStuff.runSTLcppRoutine();


The call to QLineEdit::setText() does not get updated until doStuff.runSTLCppRoutine() returns despite being physically before it. Can somebody help with this?

Many Thanks.

[NullPointer]

Hi,

You didn't give the time to loop event call the paint() event from QLineEdit...
You can use the QCoreApplication::processEvents() after setting the text.

Hth.

[Ishtar]

Thank you very much for your help

Unfortunately
QCoreApplication::processEvents() has a bizarre effect.

Here is a snipet of my code.




void Ui_MainGUI::startMainRoutine() {

string errTxt;
double testValue;

wxParameters wxStn;

if(w->toolBox_WX->currentIndex() == 0){

wxStn.stnName = "Lacrosse WS2300";
wxStn.stnInterface = "SERIAL";
wxStn.stnProtocol = "SERIAL";

wxStn.stnPort = w->cmbo_2300Port->currentText().toLocal8Bit().data();
wxStn.stnDataBit = w->cmbo_2300DataBits->currentText().toLocal8Bit().data();
wxStn.stnParity = w->cmbo_2300Parity->currentText().toLocal8Bit().data();
wxStn.stnStopBit = w->cmbo_2300StopBits->currentText().toLocal8Bit().data();

wxStn.stnBaud = w->cmbo_2300Speed->currentText().toInt();
wxStn.stnPollFreq = w->spin_2300PollFreq->text().toInt();
wxStn.stnRetries = w->spin_2300Retries->text().toInt();
wxStn.stnTimeout = w->spin_2300Timeout->text().toInt();

}

w->ledt_2300Status->setText("Connecting...");
QCoreApplication::processEvents();

if(!(MainRoutine.connStn(wxStn, stnNumber, &errTxt))){
w->ledt_2300Status->setText("ERROR");
QString err = QString::fromStdString(errTxt);
QMessageBox::critical(this, tr("ERROR"), tr("%1").arg(err));
return;
}

w->ledt_2300Status->setText("Testing Connection.");
QCoreApplication::processEvents();

if(!(MainRoutine.testStn(stnNumber, &testValue, &errTxt))){
w->ledt_2300Status->setText("ERROR");
QString err = QString::fromStdString(errTxt);
QMessageBox::critical(this, tr("ERROR"), tr("%1").arg(err));
return;
}

w->ledt_2300Status->setText("ACTIVE");

return;
}



1] wxParameters wxStn is a struct which looks like this:



struct wxParameters {

const char *stnName;
const char *stnInterface;
const char *stnProtocol;
const char *stnPort;
const char *stnDataBit;
const char *stnParity;
const char *stnStopBit;
int stnBaud;
int stnPollFreq;
int stnTimeout;
int stnRetries;

};


2] The call at line 29 fails because wxStn.stnPort is full of garbage.

If I take the processEvents() away then the code works perfectly alas without the QLineEdit being updated until the call returns.

Do you have any idea why my const char *stnPort is full of garbage?

Many thanks
Nikki

[stampede]

Do you have any idea why my const char *stnPort is full of garbage?
Yeah, because you are pointing to a block of memory that is no longer valid:

char * ptr = currentText().toLocal8Bit().data()
this is something like:


char * ptr;
{
QByteArray str = "something";
ptr = str.data();
}
// is it ok to use ptr here ? not really

You should allocate your strings with malloc() and use sprintf or memcpy to initialize it.
Or even better, use QString instead (if you can).

[Ishtar]

Sorry, I was being silly.

In the end I used std::string and then converted to const char later on because QString's are not appropriate for my application.

Many thanks.
Nikki