Signals and slots Connect

Core2

Hi All,

If I have two forms, mainview and profilesearch, and am setting up a signal and slot between them.
What should the connect ~~all~~ line look like?
The current issue I'm having is i'm using "this" twice in the send object and the receive object. This is the error I get:
"QObject::connect: No such slot ProfileSearch::printData(QString) in ..\profilesearch.cpp:80
QObject::connect: (sender name: 'ProfileSearch')
QObject::connect: (receiver name: 'ProfileSearch')"

This makes sense because I'm trying to connectl from profilesearch to profilesearch. But the class member function printData(QString); belongs to mainview. This brings me to my questions what should I replace the second "this" in the connect line of code? I've tried "MainView", "mainview", "MainView::mainview" Nothing I've tried works. What am I missing here?

The following code only includes what I think should be stuff pertaining to my question. (I cut the fat)

mainview.h

private slots:
    void printData(QString);

mainview.cpp

MainView::MainView(QWidget *parent) :
    QDialog(parent),
    ui(new Ui::MainView)
{
    ui->setupUi(this);
}
void MainView::printData(QString tnum)
{
        ui->LbltNum->setText(tnum);
}

profile.h

signals:
void sendData(QString);

profilesearch.cpp

void ProfileSearch::on_btnOk_clicked()
{
    connect(this, SIGNAL(sendData(QString)), this, SLOT(printData(QString)));
    emit sendData("test");
    qDebug() << "Ok button clicked.";
}

mrjj

Hi
-What am I missing here?
That you need a actual pointer to the widgets. So
unless you give ProfileSearch a pointer to the MainView, it cant work.

You should connect in MainView instead.
Where you create ProfileSearch to show it.

There you know both objects


void MainView::ShowProfileSearch() {
ProfileSearch ps;
connect(&ps, SIGNAL(sendData(QString)), this, SLOT(printData(QString)));
ps.exec();
}

Alternatively, you can cast the parent of ShowProfileSearch if its MainView and connect that way. Its slightly ugly though.

Core2

@mrjj
Thank you for your quick response! This WORKED!!!!!!!!!!!

Seriously thank you! I've been struggling with this for far too long.

mrjj

@Core2
You are welcome :)

it takes some time to get used to design/program
with signals and slots.
It can be a bit of a challenge to have pointers to both objects in same place but often the mainwindow is a good place.

Note that its also ok to connect signal to signal.
This can be used to surface some signals from inside a class to outside world.
Like if you have a dialog with an TextEdit. The textEdit is private so outside cannot
connect directly to it.
You can then connect signal to a new public signal and the outside world can connect to this new signal. ( like TextReady)

The good thing about this is that if you one day change the TextEdit to a combobox, the rest of the program do not need to change. It will still get the data via the new public signal TextReady.
In a non trivial program, such encapsulation/hiding of details is
worth every penny.