How to access UI elements from subclass.

[NuMs]

Hello!

New to QT.

My current project has one GBUI and I need to be able to access elements of the UI from subclasses. None of the subclasses have a UI.

How do I pass Ui::MainWindow to subclasses?

I've tried to pass it through the constructor like below:

SubClass::SubClass(Ui::MainWindow mw) {
Ui::MainWindow mw = mw;
}

Which of course doesn't work.

Any help would be appreciated.
Thanks

[kenchan]

If you must do it that way why not just pass the pointer of your main window?
Then you could make the ui pointer available through a getter, or just make it public.

[jsulm]

@NuMs If this subclasses are not UI classes why should they have direct access to the UI? It sounds like bad software design. You should rather use signals/slots to communicate between these classes and UI classes.

[JonB]

@jsulm
Just OOI, if the sub-classes have "no UI", how would they even do slots/signals between themselves and UI layer?

[mrjj]

@JNBarchan
They just need to be QObjects and have the Q_OBJECT macro to send/get signals.

[jsulm]

@JNBarchan "how would they even do slots/signals between themselves and UI layer?" - not sure I understand the question. Signals/Slots can be used between any type of classes, the only requirement is: they need to be derived from QObject (QObject isn't a UI class).

[JonB]

@jsulm
TBH, I'm not I exactly sure I understand my own question!

@mrjj & you explained the practicalities --- you just need a QObject. (I am PyQt, so I don't have a "Q_OBJECT macro", but I guess PyQt's QObject() automatically has that present if I use such an object or inherit from it?)

My question was more of a "conceptual" one. If the OP has subclasses "with no UI", they are divorced from the UI, so I don't really see how they & the UI would know which signals to exchange/place slots on. But it's a bit of a woolly question....!