QDialog with Qt::WindowModal on mac

[divide]

I need a blocking QDialog (the main app below should be inactive while it is shown) which is able to display sub-windows on top of it. I'm using this QDialog to display VST plugins, which are free to create multiple sub-windows if needed.

If I set it ApplicationModal, the QDialog is displayed fine, but any sub-windows is shown under the QDialog and therefore cannot be used.

ApplicationModal QDialog with no plugin shown

ApplicationModal QDialog with a plugin trying to show a sub-window (displayed behind the QDialog and inaccessible)

If I set it WindowModal, the sub-windows display and works as expected (on top of the QDialog), but the QDialog itself looks weird : it shares its title bar with the main application, and cannot be moved without moving the whole application.

WindowModal QDialog with no plugin shown; notice the title bar shared with the main application

WindowModal QDialog with a plugin showing a sub-window on top, as expected

So... I'm kinda stuck here. Is there a way to make a QDialog WindowModal while keeping its own title bar and freedom of movement over the main application, like the ApplicationModal dialog does ?

I'm using Qt 5.15 on macOS Catalina.

[SGaist]

Hi,

WindowModal and ApplicationModal are two different concepts. AFAIK, on macOS, the style for window modal dialog is to be shown as sheets like you see there.

[divide]

Ah, so it's by design and can't be tweaked.
In that case, do you know if I can show my dialog as non-modal (because it allows plugins to create sub-windows as expected) but somehow block the input events from my main window while this dialog is shown ? So it would act like a modal dialog, but I would handle the blocking/unblocking of the main window manually.

[krypton-001]

Hi @SGaist I am also facing the same issue as said by @divide

[Kevin Hoang]

@divide said in QDialog with Qt::WindowModal on mac:

Is there a way to make a QDialog WindowModal while keeping its own title bar and freedom of movement over the main application, like the ApplicationModal dialog does ?

I'm not completely sure I got your issue right, but have you tried setting it up like this?

dialog->setWindowModality(Qt::WindowModal);
dialog->setWindowFlags(Qt::Dialog | Qt::Window);

[krypton-001]

Currently, my dialog is something like this (see attached image) i..e no title bar. I want it to be a modal which blocks interaction with it's parent and at the same show title bar. Above solution doesn't works for mac. However below code works fine on ubuntu 22.04. I think this is platform specific issue.

class MyDialog(QtWidgets.QDialog):
    def __init__(self, parent=None):
        super().__init__(parent=parent)
        self.setWindowTitle("My Dialog")

        # Set modality to WindowModal
        self.setWindowModality(Qt.WindowModal)

        # Set appropriate window flags
        # self.setWindowFlags(Qt.Dialog | Qt.Window)

        # Set up the layout
        layout = QtWidgets.QVBoxLayout(self)
        layout.addWidget(QtWidgets.QLabel("This is a dialog!"))
        self.setLayout(layout)


class MainWindow(QtWidgets.QMainWindow):
    def __init__(self):
        super().__init__()
        self.setWindowTitle("Main Window")
        self.setGeometry(100, 100, 300, 200)

        # Add a button to the main window
        self.button = QtWidgets.QPushButton("Show Dialog", self)
        self.button.setGeometry(100, 80, 100, 40)
        self.button.clicked.connect(self.show_dialog)

    def show_dialog(self):
        dialog = MyDialog(self)  # Create dialog with main window as parent
        dialog.show()  # Show the dialog (exec creates a modal dialog)

This is how it looks on Ubuntu----