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....!