QWizardPage question

HoMa

Hi all and thank you for your time.
For my little db app I want to have a wizard with a page, on which there are two radio buttons and a combo box. The first radio button should be selected by default. The combo box should be disabled -> no problem so far.
.However: the combo box should be enabled, when the second of the two radio buttons is pressed.
How can I achieve this?
Best regards
Holger

HoMa

@jsulm - you are right, sorry. This is current - but it does not link with an error "undefined reference to vtable" ...

class wizNewOrExistingPage : public QWizardPage
{
    Q_OBJECT
public:
    wizNewOrExistingPage(QWidget* );
    void initializePage() override;
public slots:
    void onExistingCreditor_toggled(bool );
...

wizNewOrExistingPage::wizNewOrExistingPage(QWidget* p) : QWizardPage(p)
{
    rbNew =new QRadioButton(qsl("do this"));
    rbExisting =new QRadioButton(qsl("do other"));
    registerField(qsl("create_new"), rbNew);
    cbCreditors = new QComboBox();
    QVBoxLayout* l =new QVBoxLayout();
    l->addWidget(rbNew);
    l->addWidget(rbExisting);
    l->addWidget(cbCreditors);
    setLayout(l);
    connect(rbExisting, SIGNAL(toggled(bool)), this, SLOT(onExistingCreditor_toggled(bool)));
}

void wizNewOrExistingPage::onExistingCreditor_toggled(bool b)
{
    cbCreditors->setEnabled(b);
}

jsulm

@HoMa said in QWizardPage question:

How can I achieve this?

Quite easy actually: connect https://doc.qt.io/qt-5/qabstractbutton.html#toggled from the second radio button to a slot where you then call https://doc.qt.io/qt-5/qwidget.html#enabled-prop on the combo box.

HoMa

Wow - that was a quick one! Thanks a lot - I will try this.

btw: I never read the docu to QAbstractButton before ...

jsulm

@HoMa said in QWizardPage question:

QAbstractButton

It's the base class of QRadioButton
See "Inherits: QAbstractButton" in https://doc.qt.io/qt-5/qradiobutton.html
To see everything including inherited methods/properties click on "List of all members, including inherited members".

HoMa

@jsulm
:( obviously I am not "fluent" enough with signals and slots. Can you check why this does not work (this is in the contructor of the QWizardPage):

setTitle(qsl("title"));
    rbNew =new QRadioButton(qsl("do this"));
    rbExisting =new QRadioButton(qsl("select that"));
    registerField(qsl("create_new"), rbNew);
    cbCreditors = new QComboBox();
    QVBoxLayout* l =new QVBoxLayout();
    l->addWidget(rbNew);
    l->addWidget(rbExisting);
    l->addWidget(cbCreditors);
    setLayout(l);
    connect(rbExisting, &rbExisting->toggled, this, &this->onExistingCreditor_toggled);

J.Hilk

@HoMa said in QWizardPage question:

connect(rbExisting, &rbExisting->toggled, this, &this->onExistingCreditor_toggled);

this is not the correct syntax for a function pointer!

connect(rbExisting, & QRadioButton::toggled, this, &MyClass::onExistingCreditor_toggled);

HoMa

I slowly advance ;)

This

connect(rbExisting, SIGNAL(toggled()), this, 
SLOT(onExistingCreditor_toggled()));

compiles, but gives me an error at runtime:

QObject::connect: No such signal QRadioButton::toggled()

But that was what we got from the QAbstractButton, right?
One last hint ...?

jsulm

@HoMa Please read documentation https://doc.qt.io/qt-5/qabstractbutton.html#toggled
Hint: the signal has a parameter...

HoMa

@jsulm you are right again - but

connect(rbExisting, SIGNAL(toggled(bool)), this, SLOT(onExistingCreditor_toggled(bool)));

gives me

QObject::connect: No such slot QWizardPage::onExistingCreditor_toggled(bool)

:/ am I the only one who finds this confusing?

jsulm

@HoMa Because your slot does not have parameters, simply remove "bool"...
A slot is allowed to have less parameters than signal (but not the other way around).

HoMa

@jsulm 1000x thanks that you are so patient.
However: this does not do the trick. I tried both ways: with and w/o parameter in the function definition as well as in the connect call.
The error mentioned QWizardPage... shouldn't it be about my class (which is derived from QWizardPage)?
regards
Holger

jsulm

@HoMa Can you show your current connect call and slot declaration? Without code I can't tell you much.

HoMa

@jsulm - you are right, sorry. This is current - but it does not link with an error "undefined reference to vtable" ...

class wizNewOrExistingPage : public QWizardPage
{
    Q_OBJECT
public:
    wizNewOrExistingPage(QWidget* );
    void initializePage() override;
public slots:
    void onExistingCreditor_toggled(bool );
...

wizNewOrExistingPage::wizNewOrExistingPage(QWidget* p) : QWizardPage(p)
{
    rbNew =new QRadioButton(qsl("do this"));
    rbExisting =new QRadioButton(qsl("do other"));
    registerField(qsl("create_new"), rbNew);
    cbCreditors = new QComboBox();
    QVBoxLayout* l =new QVBoxLayout();
    l->addWidget(rbNew);
    l->addWidget(rbExisting);
    l->addWidget(cbCreditors);
    setLayout(l);
    connect(rbExisting, SIGNAL(toggled(bool)), this, SLOT(onExistingCreditor_toggled(bool)));
}

void wizNewOrExistingPage::onExistingCreditor_toggled(bool b)
{
    cbCreditors->setEnabled(b);
}

jsulm

@HoMa said in QWizardPage question:

"undefined reference to vtable"

Do a complete rebuild: remove build folder, run qmake and build.

HoMa

@jsulm exactly ! I just found out no my own. That is strange.

Anyhow: great! Learned a lot on signals and slots - Thanks a lot!