QObject::connect question

[kalster]

I was reading a beginners tutor on a push button that closes then a user clicks it. in qt creator I created a new qt gui application using the default file names. I then went to the form designer and put on the main window a push button.

in the mainwindow.cpp, I created the following code to put into the push button click function. The problem is that in the code &a, the "a" is defined in the main.cpp file only. I would like to close the application from the mainwindow.cpp instead but i don't know how or even if that is possible. I would like to close it in the mainwindow.cpp because that way i could do my from design in the designer, select my signal and then do the code all within the mainwindow.cpp. is that possible to do?
@void MainWindow::on_pushButton_clicked()
{
QObject::connect(&ui;->pushButton, SIGNAL(clicked()), &a, SLOT(quit()));
quit.show();
}@

here is the mainwindow.cpp code.
@#include "mainwindow.h"
#include "ui_mainwindow.h"

MainWindow::MainWindow(QWidget *parent) :
QMainWindow(parent),
ui(new Ui::MainWindow)
{
ui->setupUi(this);
}

MainWindow::~MainWindow()
{
delete ui;
}

void MainWindow::on_pushButton_clicked()
{
QObject::connect(&quit;, SIGNAL(clicked()), &a, SLOT(quit()));
quit.show();

}@

[giesbert]

Hi,

QApplication has a global variable called qApp, which you should use here:

@
void MainWindow::on_pushButton_clicked()
{
QObject::connect(&ui;->pushButton, SIGNAL(clicked()), qApp, SLOT(quit()));
quit.show();
}
@

[kalster]

the code does not work for me. any other suggestions?

[andre]

You will need to give us more than "does not work". What did not work? Did you get errors compiling? Linking? Output on the terminal when your run?

[Chuck Gao]

In
@
QObject::connect(&ui;->pushButton, SIGNAL(clicked()), qApp, SLOT(quit()));
@

"&ui;->pushButton", a wrong ";" there.

[kalster]

i solved it.

I had to change...
@&ui;->pushButton@
to...
@ui;->pushButton@
thank you for the help.

ps. yes i know about the ";". for some reason that is added in when i put "@" "@" around the code

[Chuck Gao]

All right, you can also take a look at this one "New Signal&Slot; syntax":http://developer.qt.nokia.com/wiki/New_Signal_Slot_Syntax

[andre]

That new syntax is not going to help anybody as long as it is not in any released Qt version.

[Chuck Gao]

[quote author="Andre" date="1311919259"]That new syntax is not going to help anybody as long as it is not in any released Qt version.[/quote]

Yes, but it's still a good way/article to learn Qt :D