Attempting to get signal from checkbox change

Question

The following code sets up a list of checkboxes.

QWidget *w = new QWidget(this);
w->setFixedSize(300,200);
QVBoxLayout *vbox = new QVBoxLayout;

foreach(QString filt, filters){
    QCheckBox *checkbox = new QCheckBox(filt, this);
    checkbox->setChecked(true);
    vbox->addWidget(checkbox);

    connect(this, SIGNAL(statechanged(int)), this, SLOT(cbstate(int)));

}

w->setLayout(vbox);
w->show();

The idea is that when the user checks or unchecks an item, it will emit a signal.

In the header file, I have included the following in the private slots:

void cbsate(int state);

And in the cpp file, I have declared this:

void MainWindow::cbstate(int state){
    if(state == 0){
        //unchecked
        QMessageBox::information(this, "Unchecked", "You have unchecked this box");
    }
    else if (state == 2){
        //checked
        QMessageBox::information(this, "Checked", "You have checked this box");
    }
}

I'm now getting an error of

no 'void MainWindow::cbstate(int)' member function declared in class 'MainWindow'

Any ideas? Am I going about this correctly? Thanks.

You have an error in the way you connect signal and slots try: connect(checkbox, SIGNAL(stateChanged(int)), this, SLOT(cbstate(int))); — Ramez
– Ramez, Commented Aug 6, 2013 at 10:49

dunc123 · Accepted Answer · 2013-08-06 10:34:50Z

2

It definately sounds as if you have not added the method cbstate to your header file correctly. If you copy and pasted this from your header file, then you have a typo:

void cbsate(int state);

should be:

void cbstate(int state);

answered Aug 6, 2013 at 10:34

dunc123

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3 Comments

sark9012 Over a year ago

Oops, gutted I made a typo! It's now running without any errors but when I attempt to uncheck a checkbox, I get the following errors: Object::connect: No such signal MainWindow::statechanged(int) in ../Images/mainwindow.cpp:38 Object::connect: (sender name: 'MainWindow') Object::connect: (receiver name: 'MainWindow')

dunc123 Over a year ago

You need to connect the checkbox, not the window, i.e. connect(checkbox, SIGNAL(...), this, SLOT(...));

sark9012 Over a year ago

Sorted, statechanged is stateChanged! Cheers dunc!

Rammgarot · Accepted Answer · 2016-11-30 13:11:46Z

1

To solve connect issue use:

connect(this, SIGNAL(stateChanged(int)), this, SLOT(cbstate(int)));

Note that stateChanged is used, not statechanged.

answered Nov 30, 2016 at 13:11

Rammgarot

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