How to connect a slot(QWidget*) with signal(clicked())

[revellix]

Hey mates.

I want to connect a button's clicked() signal with a custom slot that gets a QWidget as parameter. Afaik it is not possible to connect non-parameter signals with parameter slots.
How can I solve that?

connect(startButton,SIGNAL(clicked()),this,SLOT(calculationAlgoStart(subWindowTabWidget)));

connect(startButton,SIGNAL(clicked()),this,SLOT(calculationAlgoStart(subWindowTabWidget)));

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any suggestions ?

[Jonny174]

Reimplement startButton and make your signal. Maybe this help:

class PushButton : public QPushButton
{
  Q_OBJECT
 
  public:
    PushButton( QWidget *parent = 0 );
    virtual ~PushButton() {}
 
  protected:
    virtual void click();
 
  signals:
    void onClick( QWidget * );
};

class PushButton : public QPushButton
{
  Q_OBJECT
  
  public:
    PushButton( QWidget *parent = 0 );
    virtual ~PushButton() {}
    
  protected:
    virtual void click();
    
  signals:
    void onClick( QWidget * );
};

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PushButton::PushButton( QWidget *parent ):
  QPushButton( parent )
{
}
 
void PushButton::click()
{
  emit onClick( this );
}

PushButton::PushButton( QWidget *parent ):
  QPushButton( parent )
{
}

void PushButton::click()
{
  emit onClick( this );
}

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[Lykurg]

...or make an custom slot, which calls calculationAlgoStart(subWindowTabWidget).

[revellix]

...or make an custom slot, which calls calculationAlgoStart(subWindowTabWidget).

no sense. I have to give the custom slot the parameter subWindowTabWidget....

[Lykurg]

no sense.

A lot of sense, if one try to understand...

connect(startButton,SIGNAL(clicked()),this,SLOT(mySlot()));
//...
void XXX:mySlot()
{
  calculationAlgoStart(subWindowTabWidget);
}

connect(startButton,SIGNAL(clicked()),this,SLOT(mySlot()));
//...
void XXX:mySlot()
{
  calculationAlgoStart(subWindowTabWidget);
}

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And if you have more buttons you could use QSignalMapper. But this statement probably also has no sense.

[revellix]

subWindowTabWidget is a parameter that I give to the constructor... finally I have to tell the slot(), what subWindowTabWidget is. So I have again: mySlot(QTabWidget *).

Yaaa... QSignalMapper... I tried to use the class, but I dont get it. Too newbish for that. If you want to explain it, feel free to do so.

[Lykurg]

subWindowTabWidget is a parameter that I give to the constructor... finally I have to tell the slot(), what subWindowTabWidget is. So I have again: mySlot(QTabWidget *).

Umpf, ok, lets take small steps: Where is your connect statement? Does it look like

MyClass::MyClass(/*...*/, QObject* subWindowTabWidget)
{
  // Ui setup (also startButton)
  connect(startButton, SIGNAL(clicked()),
          this, SLOT(calculationAlgoStart(subWindowTabWidget)));
}

MyClass::MyClass(/*...*/, QObject* subWindowTabWidget)
{
  // Ui setup (also startButton)
  connect(startButton, SIGNAL(clicked()),
          this, SLOT(calculationAlgoStart(subWindowTabWidget)));
}

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?

[revellix]

Constructor:

UserInput::UserInput(QWidget *parent, int form, QTabWidget *subWindowTabWidget) :  QWidget(parent)
{
    this->setAttribute(Qt::WA_DeleteOnClose);
 
    this->setLayout(userInputLayout);
    this->constructUserInput(form, subWindowTabWidget);   ........
 
}

UserInput::UserInput(QWidget *parent, int form, QTabWidget *subWindowTabWidget) :  QWidget(parent)
{
    this->setAttribute(Qt::WA_DeleteOnClose);

    this->setLayout(userInputLayout);
    this->constructUserInput(form, subWindowTabWidget);   ........

}

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Constructormethod:

void UserInput::constructUserInput(int constructForm, QTabWidget *)
{
....
    connect(startButton,SIGNAL(clicked()),this, SLOT(calculationAlgoStart(QTabWidget *)));
....
}

void UserInput::constructUserInput(int constructForm, QTabWidget *)
{
....
    connect(startButton,SIGNAL(clicked()),this, SLOT(calculationAlgoStart(QTabWidget *)));
....
}

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CalculateAlgorithm...:

void UserInput::calculationAlgoStart(QTabWidget *)
{
....

void UserInput::calculationAlgoStart(QTabWidget *)
{
....

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[Lykurg]

In that case, why do you need to pass the pointer at all? Make a private member variable and use this in your slot.

class UserInput
{
  private:
    QTabWidget *m_subWindowTabWidget;
};
 
UserInput::UserInput(QWidget *parent, int form, QTabWidget *subWindowTabWidget) :  QWidget(parent), m_subWindowTabWidget(subWindowTabWidget)
{
    this->setAttribute(Qt::WA_DeleteOnClose);
    this->setLayout(userInputLayout);
    connect(startButton,SIGNAL(clicked()),this, SLOT(calculationAlgoStart()));
}
 
void UserInput::calculationAlgoStart(QTabWidget *)
{
  // simple use m_subWindowTabWidget here
}

class UserInput
{
  private:
    QTabWidget *m_subWindowTabWidget;
};

UserInput::UserInput(QWidget *parent, int form, QTabWidget *subWindowTabWidget) :  QWidget(parent), m_subWindowTabWidget(subWindowTabWidget)
{
    this->setAttribute(Qt::WA_DeleteOnClose);
    this->setLayout(userInputLayout);
    connect(startButton,SIGNAL(clicked()),this, SLOT(calculationAlgoStart()));
}

void UserInput::calculationAlgoStart(QTabWidget *)
{
  // simple use m_subWindowTabWidget here
}

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[revellix]

see... this is why I am too newbish. THX mate.

how is this parameter substitution called ? I should read something about that.

[Lykurg]

It is simple use of private members. Nothing special. If you mean the initialization of members alongside the c-tor, see (constructor) initialization lists.