QWizard - back button missing

Question

I have a QWizard, which branches in a following way:

           ----- Page1 -----
         /                   \
StartPage  - Page2 - Page3 -  EndPage
         \                   /
           ----- Page4 -----

The problem is, the the end page only shows "back" button, when it's reached via StartPage -> page4 -> EndPage. Otherwise it only shows "finish" and "cancel". Does anyone have similar experiences, what could cause this? Here's how it's set up:

QWizard wizard;
wizard.setPage(0, new StartPage(&wizard));
wizard.setPage(1, new Page1(&wizard));
wizard.setPage(2, new Page2(&wizard));
wizard.setPage(3, new Page3(&wizard));
wizard.setPage(4, new Page4(&wizard));
wizard.setPage(5, new EndPage(&wizard));

For the pages, nextId() is reimplemented to return correct id. I'm confused why it works differently via different paths.

Answer 1

Nobody can know what is wrong because you do not show your implementation so I will just provide a code that implements the scheme that shows:

wizard.h

#ifndef WIZARD_H
#define WIZARD_H

#include <QWizard>

class QButtonGroup;

class Wizard : public QWizard
{
    Q_OBJECT
public:
    enum { Start_Page,
           Page_1,
           Page_2, Page_3,
           Page_4,
           End_Page };
    Wizard(QWidget *parent=nullptr);
};

class StartPage: public QWizardPage
{
    Q_OBJECT
public:
    StartPage(QWidget *parent=nullptr);
    int nextId() const override;
private:
    QButtonGroup *group;
};

class Page1: public QWizardPage
{
    Q_OBJECT
public:
    Page1(QWidget *parent=nullptr);
    int nextId() const override;
};

class Page2: public QWizardPage
{
    Q_OBJECT
public:
    Page2(QWidget *parent=nullptr);
    int nextId() const override;
};

class Page3: public QWizardPage
{
    Q_OBJECT
public:
    Page3(QWidget *parent=nullptr);
    int nextId() const override;
};

class Page4: public QWizardPage
{
    Q_OBJECT
public:
    Page4(QWidget *parent=nullptr);
    int nextId() const override;
};

class EndPage: public QWizardPage
{
    Q_OBJECT
public:
    EndPage(QWidget *parent=nullptr);
    int nextId() const override;
};
#endif // WIZARD_H

wizard.cpp

#include "wizard.h"

#include <QButtonGroup>
#include <QLabel>
#include <QRadioButton>
#include <QVBoxLayout>

Wizard::Wizard(QWidget *parent):
    QWizard(parent)
{
    setPage(Start_Page, new StartPage);
    setPage(Page_1, new Page1);
    setPage(Page_2, new Page3);
    setPage(Page_3, new Page3);
    setPage(Page_4, new Page4);
    setPage(End_Page, new EndPage);
}

StartPage::StartPage(QWidget *parent):
    QWizardPage(parent)
{
    QVBoxLayout *lay = new QVBoxLayout(this);
    lay->addWidget(new QLabel("Start Page"));
    group = new QButtonGroup(this);
    for(const QString & text: {"Page1", "Page2", "Page4"}){
        QRadioButton *radio = new QRadioButton(text);
        lay->addWidget(radio);
        group->addButton(radio);
    }
    group->buttons().first()->setChecked(true);
    lay->addStretch();
}

int StartPage::nextId() const
{
    if(group->checkedButton()->text() == "Page1")
        return Wizard::Page_1;
    else if(group->checkedButton()->text() == "Page2")
        return Wizard::Page_2;
    return Wizard::Page_4;
}

Page1::Page1(QWidget *parent):
    QWizardPage(parent)
{
    QVBoxLayout *lay = new QVBoxLayout(this);
    lay->addWidget(new QLabel("Page1"));
}

int Page1::nextId() const
{
    return Wizard::End_Page;
}

Page2::Page2(QWidget *parent):
    QWizardPage(parent)
{
    QVBoxLayout *lay = new QVBoxLayout(this);
    lay->addWidget(new QLabel("Page2"));
}

int Page2::nextId() const
{
    return Wizard::Page_3;
}

Page3::Page3(QWidget *parent):
    QWizardPage(parent)
{
    QVBoxLayout *lay = new QVBoxLayout(this);
    lay->addWidget(new QLabel("Page3"));
}

int Page3::nextId() const
{
    return Wizard::End_Page;
}

Page4::Page4(QWidget *parent):
    QWizardPage(parent)
{
    QVBoxLayout *lay = new QVBoxLayout(this);
    lay->addWidget(new QLabel("Page4"));
}

int Page4::nextId() const
{
    return Wizard::End_Page;
}

EndPage::EndPage(QWidget *parent):
    QWizardPage(parent)
{
    QVBoxLayout *lay = new QVBoxLayout(this);
    lay->addWidget(new QLabel("End Page"));
}

int EndPage::nextId() const
{
    return -1;
}

main.cpp

#include "wizard.h"
#include <QApplication>

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    Wizard w;
    w.show();
    return a.exec();
}

The complete example can be found here.