Update Windows Title in Embedded Application

Kashif

Hi All,
I have developed a simple ticket booking application, set the windows title using "setWindowTitle" method and its working fine. Now I have two methods connected to two push buttons "New Booking" and "Cancel Booking"
Now I want, when someone press "New Booking" button, the main window title should be updated to "New Booking" and for "Cancel Booking" the same accordingly.
I tried to use "setWindowTitle" inside "newBooking" method it it is giving me segmentation fault.
Hope to get help accordingly.

Thanks

applqpak

@Kashif Hello,

Do you have any code?
I created a quick test app that calls setWindowTitle() in a slot when a QPushButton is clicked in Qt Creator, everything works fine

Not clicked:
alt text
Title changes when button is clicked:

Kashif

Hi @applqpak,

Sorry I missed to mention that I am working on embedded device with Linux kernel, using QTopia+widget application.

Following is code snippet for your reference:

//main.cpp

#include "gprs_connect.h"
#include <qtopiaapplication.h>

QTOPIA_ADD_APPLICATION(QTOPIA_TARGET, GPRSConnect)
QTOPIA_MAIN


//gprsConnect.cpp
GPRSConnect::GPRSConnect(QWidget *parent, Qt::WindowFlags f)
        : QMainWindow(parent, f)
{

    setWindowTitle("Easy Ticket");   //This works fine

    centralWidget = new QWidget(this);
    layout = new QVBoxLayout(centralWidget);
    QString label_state;

    label_state="Select Your Option";

    lblTranName = new QLabel("IDLE MENU", centralWidget);
    layout->addWidget(lblTranName);

    lblTranMsgs = new QLabel(label_state, centralWidget);
    layout->addWidget(lblTranMsgs);

    layout->addStretch();

    purButton = new QPushButton(tr("Purchase"), centralWidget);
    connect(purButton, SIGNAL(clicked(bool)), SLOT(Purchase()));
    layout->addWidget(purButton);

    refundButton = new QPushButton(tr("Refund"), centralWidget);
    connect(refundButton, SIGNAL(clicked(bool)), SLOT(refund()));
    layout->addWidget(refundButton);

    quitButton = new QPushButton(tr("Quit"), centralWidget);
    connect(quitButton, SIGNAL(clicked(bool)), SLOT(close()));
    layout->addWidget(quitButton);

    layout->setMargin(0);
    layout->setSpacing(0);
    setCentralWidget(centralWidget); 

}


void GPRSConnect::Purchase()
{
    QFont fontDef = lblTranMsgs->font();
    QFont fontNew = lblTranMsgs->font();
    fontNew.setBold(true);
    lblTranMsgs->setFont(fontNew);
    lblTranMsgs->update();
    lblTranMsgs->repaint();
	
    //setWindowTitle("PURCHASE");   //Segmentation Fault
    QWidget::setWindowTitle("PURCHASE");   //Segmentation Fault

}

SGaist

Hi,

Qtopia ? Are you locked to it ? That's a project that has reached EOL 8 years ago so it's not necessarily a good idea to start a new project with it.

Kashif

Hi @SGaist,
Its a new device for me, and I am following the base code provided by the device vendor. I don't know how to change the architecture and if i do something how to make it work on device.
I tried hello world ui application, compiled successfully but it gives me run time exceptions on device.

Hope this answers your query.

Thanks

SGaist

You should check with the vendor if you can use something a bit more recent.

As for your error, can you get a stack trace ?

Kashif

Hi @SGaist,

Sorry for delayed response as I am woking in Qatar and we have weekend for Friday/Saturday.
I tried again the same thing and I am not getting exception now, no idea what I had done before, may be some uninitialized pointer that I may have fixed when moving forward to application logical code.
Currently as I mentioned that I am not getting exception but issue is that the main window title is getting updated when the control is returned back to main constructor. Also to mention that I have disabled the push buttons in the same function and that code is working fine:
For the main window title I have placed following line of code:

    setWindowTitle("PURCHASE");
    centralWidget->update();
    centralWidget->repaint();

Thanks

SGaist

The QMainWindow title has nothing to do with the central widget.

Kashif

Hi @SGaist,
Can you please write me a line or reference on how do to update QMainWindow title in my code as I am not using "ui" component so its something unknown for me.

Thanks

SGaist

Well:
@Kashif said in Update Windows Title in Embedded Application:

setWindowTitle

of your QMainWindow is the right method AFAIR.

Can you show what you get ?

Kashif

Hi @SGaist,

I used this function in my code but the title is getting updated only when the control returns back to push button calling event (the class constructor where I have defined central widget and buttons, code is pasted in third comment)

Thanks

SGaist

Why are you calling QWidget::setWindowTitle rather than just setWindowTitle ?

Kashif

Hi @SGaist,

I tried both and the outcome is same.

Thanks