How to execute a MainWindow method from Dialog class

CarlosQ

Hello, everyone. I hava a method in MainWindow class named ShowText() (for example) that writes a text in a line edit.

void MainWindow::ShowText()
{
ui->leText->setText("I write this text");
return;
}
and I want execute this method from a Dialog form to push a button.

What code have I to write when the pushButton is clicked?

void Dialog::on_pbSText_clicked()
{
// ¿ ....... ?
}

Thanks in advance!

raven-worx

easiest would probably be to connect a dialog signal (connected to the button's clciked signal) with the main window slot.

jsulm

Yes, as raven-worx sad you should emit a signal from your dialog which you can connect to a slot in your MainWindow.
The dialog should not know anything about MainWindow and what it does if a button is clicked in the dialog.

ValentinMichelet

Hi, welcome to Devnet,

As I explained in this similar post
https://forum.qt.io/topic/61728/how-to-access-methods-of-mainwindow-from-dialog-form-subclassing-i-guess/3

As a rule of thumb, I recommend you to make connections from the parent widget, who is aware of it's children since children are often created from parent widget:

the main window creates the dialog;
the dialog can emit a signal when its button is pushed;
the main window connects this signal to a custom slot;
the slot processes the dialog information.

Moreover, creating connections from the parent widget enables you to make two children communicate between them, without having to know each other.

CarlosQ

Well, I declared the method in "mainwindow.h" as public slots:
public slots:
void ShowText();

Then, in the "dialog.cpp" constructor:
connect(ui->pbSText,SIGNAL(clicked()),parent, SLOT(ShowText()));

but it do nothing.
When i push "pbSText" button i think the slot "ShowText()" was execute but nothing happend.

What is wrong?.
Thanks a lot.

ValentinMichelet

No, the connect is in the MainWindow constructor:

connect(myDialog, SIGNAL(clicked()), this, SLOT(ShowText()));

If you want your dialog to emit a signal when its ui->pbSText emits the clicked signal, then declare a clicked signal in dialog.h:

signals:
  void myClicked();

Then connect it from your constructor in dialog.cpp:

connect(ui->pbSText,SIGNAL(clicked()), this, SIGNAL(myClicked()));

To check if a SLOT is really called, just output some stuff, using qDebug(), or std::cout, or anything you like to print messages.

CarlosQ

GOOD, it works fine.

But the connect in MainWindow is:
connect(myDialog, SIGNAL(myClicked()), this, SLOT(ShowText()));

Thanks a lot.
I'm very happy.

ValentinMichelet

@CarlosQ said:

But the connect in MainWindow is:
connect(myDialog, SIGNAL(myClicked()), this, SLOT(ShowText()));

Exaxctly, that means you understood what I was talking about =)

Thanks a lot.
I'm very happy.

Glad to hear that!