Problem with QGeoLocationInfoSource

[robnugent]

Hi,

I'm trying to write a trivial QT program that uses the location API.

I'm using QT Creator 1.3.83.

When I run the program in the simulator, all is OK and I can determine (and display) my location OK.

However, when I run it on my phone (A Nokia 5800) from QT Creator, I get the following

Process 1529, thread 1530 stopped at 0x802a12f1: Thread 0x5fa has panicked. Category: Lbs Client Fault; Reason: 6

This is triggered by the line of code:

source = QGeoPositionInfoSource::createDefaultSource(parent);

If anyone can suggest what I'm doing wrong, I'd very much appreciate it.

Thanks,
Rob

[robnugent]

Sorry about the thread title - It should of course have read QGeoPositionInfoSource.

[robert26]

Hi Rob,

first of all, don't be surprised if something works on your Windows(?) maschine and then does not work/works differently on your target device. Welcome to cross-platform development ;-).

Are you sure that the panic really happens here?

source = QGeoPositionInfoSource::createDefaultSource(parent);

QGeoPositionInfoSource code looks okey. In fact, QGeoPositionInfoSource::createDefaultSource traps potential leaves of CQGeoPositionInfoSourceS60::NewL. So, I wonder how you can get a panic there ...

[robnugent]

Rob,

Thanks for the reply. It's definitely this line of code, as I stripped my example back so that this is the *only* line in my example that does anything with the location API.

The rest of my application just displays "Hello World" on the screen. If I comment out the line of code above, it all runs find on my 5800. If I uncomment it I see the panic.

I guess it could be happening on another thread, if the createDefaultSource has started such a thread. I'm afraid I'm not clued up enough to know how to tell...

Here's the code:

main.cpp:

#include <QtGui/QApplication>
#include "loctest.h"

int main(int argc, char *argv[])
{
QApplication a(argc, argv);
LocTest w;
#if defined(Q_WS_S60)
w.showMaximized();
#else
w.show();
#endif
return a.exec();
}


loctest.h:

#ifndef LOCTEST_H
#define LOCTEST_H

#include <QtGui/QMainWindow>
#include <QObject>
#include <QGeoPositionInfoSource>
#include <QGeoPositionInfo>

QTM_USE_NAMESPACE

class LocTest : public QMainWindow
{
Q_OBJECT

public:
LocTest(QWidget *parent = 0);
~LocTest();

protected:
void paintEvent(QPaintEvent *event);

private:
QGeoPositionInfoSource *source;

};

#endif // LOCTEST_H

loctest.cpp:
#include <QtGui>
#include "loctest.h"

LocTest::LocTest(QWidget *parent)
: QMainWindow(parent)
{
source = QGeoPositionInfoSource::createDefaultSource(parent);
}

LocTest::~LocTest()
{

}

void LocTest:aintEvent(QPaintEvent *) {
QPainter p(this);
p.setRenderHint(QPainter::Antialiasing);

QColor w = QColor("red");
p.fillRect(0,0,200,200,w);

QString m1;
QTextStream(&m1) << "Hello World";
QColor b = QColor("black");
p.setPen(b);
p.drawText(8,20, m1);
}

I'm not the world's strongest C++ coder (my background's Java), so this could be a trivial error on my part, but if there is, I can't see it.

[robnugent]

OK - I've managed to fix it. Here's the solution for anyone else who hits the same issue:

In my project file I was missing the following:

symbian {
TARGET.UID3 = 0xeb20e322
TARGET.CAPABILITY = Location
TARGET.EPOCSTACKSIZE = 0x14000
TARGET.EPOCHEAPSIZE = 0x020000 0x800000
}

(TARGET.CAPABILITY was commented out). Correcting this lines and doing a clean rebuild left things working.

Rob - thanks for your help anyhow.

Rob

[robert26]

Hi Rob,

great that you figured it out!

Just for your information: Cause I figured that it wasnt you who commented that line, I quickly searched the Qt mobility bug reports. Et voila! This commented line is acutally not bug, its a feature:

http://bugreports.qt.nokia.com/browse/QTMOBILITY-37

Quote from the report:
"Some of the Mobility libraries have a commented out line in their .pro files describing the minimum set of capabilities required by the libraries themselves. This should make things easier for the users that feel the need to modify the libraries themselves."

[anothertest]

Hi,

I am experiencing the same error. However both my application and the location library are built with All -tcb capabilities and yet I receive the same error.

Was there anything else you modified or changed?

Cheers