Modal Dialogs?

[npwoods]

Is there a canonical technique to create modal dialogs in Slint?

I can't speak for other platforms, but on Windows this requires passing specific parameters to the API that creates a window (CreateWindowEx), and I suspect that this might be quite gross if I tried to do it on my own.

[Horbin-Magician]

You can use PopupWindow, ref: https://releases.slint.dev/1.7.2/docs/slint/src/language/builtins/elements.html#popupwindow.
Besides, Slint now supports multiple Windows, so you can new a window as the modal dialog instead of using CreateWindowEx.

[npwoods]

PopupWindow is inadequate; it appears to be the equivalent of a HTML popup implemented with a span tag.

I want to have a modal popup that is equivalent to what you get in WIndows notepad.exe if you try to exit without saving changes. Unless I'm mistaken, this cannot be achieved in Slint without overriding the winit's creation of the Window because in Win32, you have to specify the modal parent as the hwndOwner parameter to CreateWindowEx.

[npwoods]

modal-hack-demo.zip

I was able to hack something together that will create a real Win32 modal dialog with Slint that properly blocks the underlying Window. I'm hoping that there will be a better way to do this because:

• This solution is Windows specific
• The modal dialog is not centered on the parent properly
• When the modal dialog is closed, focus to the underlying window seems to lost
• This is a disgusting hack

[Enyium]

There's also SetParent() that allows you to set the owner, not just CreateWindowExW(). More on owned windows. And this article from Raymond Chen is also relevant: The correct order for disabling and enabling windows.

[npwoods]

Yes, that is extremely relevant - my hacky solution creates an object whose sole purpose is to reenable the window (WindowReenabler) when dropped, and attaches it to the window as a bogus rendering notifier with set_rendering_notifier(). Honestly, I'm not sure if this gets the ordering right nor not. And I really don't want to be doing platform specific stuff just to show a modal dialog.