No signal is emitted in testing for signals and slots

[VRonin]

make sure all the connections were successful. My recommendation is to use Qt5 connection syntax but if you stick with Qt4 version then wrap the connect statement in a Q_ASSUME() (so it asserts if the connection fails)

Q_ASSUME(connect(plusButton,SIGNAL(addbuttonClicked()),this,SLOT(additiveOperatorClicked())));

[shravan_121]

It shows me error ::Qobject::connect:no such signal Button::additivieoperatorClickedsignal()

[J.Hilk]

@shravan_121
pls post your whole connect statement

[shravan_121]

calculator.h:
class Calculator : public QWidget
{
Q_OBJECT

public:
Button *plusButton;
Button *minusButton;
Button *timesButton;
Button *divisionButton;
Calculator(QWidget *parent = 0);
public slots:
void digitClicked();
void additiveOperatorClicked();
void multiplicativeOperatorClicked();
signals:
void addbuttonClicked(const QString &data);
void multiplybuttonClicked(const QString &data);
void digitclickedsignal(const QString &data);

calculator.cpp:
Calculator::Calculator(QWidget *parent)
: QWidget(parent)
{
plusButton = createButton(tr("+"), SLOT(additiveOperatorClicked()this));

connect(plusButton,SIGNAL(addbuttonClicked()),this,SLOT(additiveOperatorClicked()));

void Calculator::additiveOperatorClicked()
{
Button *clickedButton = qobject_cast<Button *>(sender());
QString clickedOperator = clickedButton->text();
double operand = display->text().toDouble();
if (!pendingMultiplicativeOperator.isEmpty()) {
//! [12] //! [13]
if (!calculate(operand, pendingMultiplicativeOperator)) {
abortOperation();
return;
}
display->setText(QString::number(factorSoFar));
operand = factorSoFar;
factorSoFar = 0.0;
pendingMultiplicativeOperator.clear();

}

if (!pendingAdditiveOperator.isEmpty()) {
    if (!calculate(operand, pendingAdditiveOperator)) {
        abortOperation();
        return;
    }
    display->setText(QString::number(sumSoFar));
} else {
    sumSoFar = operand;
}
pendingAdditiveOperator = clickedOperator;
waitingForOperand = true;

 emit addbuttonClicked(tr("+"));

[Bondrusiek]

@shravan_121 On first view you have bad syntax. Look on signal emit addbuttonClicked(tr("+")); which has one argument QString. In connect function you use signal without argument ```
connect(plusButton,SIGNAL(addbuttonClicked()),this,SLOT(additiveOperatorClicked()));.
Try to replace signal on
void addbuttonClicked()
or change function slot with one argument ie

void additiveOperatorClicked(QString)

and use this in connect

connect(plusButton,SIGNAL(addbuttonClicked(QString)),this,SLOT(additiveOperatorClicked(QString)));

[shravan_121]

But after that i am getting same error: no such signal additiveoperatorclicked(QString)
no such slot addbuttonclicked(QString)

[VRonin]

@shravan_121 said in No signal is emitted in testing for signals and slots:

no such signal Button::additivieoperatorClicked

And this is the problem additivieoperatorClicked is a signal of Calculator not of Button. You are trying to connect with a receiver being a pointer to Button

[shravan_121]

@VRonin I dont know the actual solution can you please suggest a possible solution for the error.

[shravan_121]

This post is deleted!

[shravan_121]

I don't know the actual solution can you please suggest a possible solution for the error.

[VRonin]

@shravan_121 said in No signal is emitted in testing for signals and slots:

connect(plusButton,SIGNAL(addbuttonClicked()),

The problem is here. addbuttonClicked is a signal of Calculator but plusButton is of type Button.
So either the sender (the first argument) or the signal (the second) must be changed to make sense