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:

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