Why is QT telling me my QDialog inherited class is not a QWidget?

Question

I'm trying to create/add a dialog to my application - To explain why the name of the dialog - it's to allow configuration/settings to be maintained such as themes/styles, and such so it's called SettingsDialog. For whatever reason, I'm getting no errors in the header file but I get errors in the cpp file - at first it was yelling at me that the constructor looked like a constructor but was not one or something like that - I seemed to fix that just by applying bodies to every other method (even though I've never got that error before). Now when I'm trying to create a QSplitter, it's telling me 'this' is not a QWidget when it refers to this class, a QDialog which according to the QT documentation is inherited from QWidget. I feel like there's a typo somewhere I'm missing maybe. Please I hope someone can see the blockage and help me resolve it.

Before anyone complains about it being not as simple as they'd like it - I include only the bare minimum methods and items - Every widget I create has an initPanel/Window/Dialog method and an initControls method that is called from the other init method after other configurations. As you can see, in the constructor, I call initDialog. I put my classes in a namespace - sure it may be a lot of white space but if by removing the namespace section it fixes it - that doesn't fix it for me - The namespaces are essential so I need a solution that keeps them in the code which is why I have not removed them. Otherwise, I can't strip anything else out. More will end up going in there eventually when I get this part to stop erroring in build, so cutting out the init methods even though they're not being called now won't help anything one bit.

SettingsDialog.h:

#pragma once

#include <QDialog>
#include <QSplitter>

namespace net
{
    namespace draconia
    {
        namespace mediadb
        {
            namespace ui
            {
                class SettingsDialog : public QDialog
                {
                    Q_OBJECT

                    QSplitter *mPnlSplitter;
                protected:
                    QSplitter *getSplitter() const;
                    void initControls();
                    void initDialog();
                public:
                    SettingsDialog(QWidget *parent = nullptr);
                };
            }
        }
    }
}

SettingsDialog.cpp:

#include "SettingsDialog.h"

using namespace net::draconia::mediadb::ui;

QSplitter *SettingsDialog::getSplitter() const
{
    if(mPnlSplitter == nullptr)
        {
        mPnlSplitter = new QSplitter(Qt::Orientation::Horizontal, this);  // Error - no matching constructors evidently
        }
}

void SettingsDialog::initControls()
{ }

void SettingsDialog::initDialog()
{ }

SettingsDialog::SettingsDialog(QWidget *parent)
    :   QDialog(parent)
    ,   mPnlSplitter(nullptr)
{
    initDialog();
}

Answer 1

1. You try to change the mPnlSplitter member in the const getSplitter() method.
2. QSplitter's constructor accepts QWidget *, not const QWidget *

Also note that QSplitter *SettingsDialog::getSplitter() const should return a value, but there is no return in the method.