SIGNAL AND SLOT

ashokkalbhor

I want to connect this two variables sampTime,sigFreq by using the spinbox or slider using the signal slot technique

for ( int i=0; i<101; ++i)
{
x[i] = isampTime;
y[i] = sin(23.14sigFreqx[i]);
}

i tried something like this
connect(ui->doubleSpinBox, SIGNAL(valueChanged(double)),sampFreq,SLOT(displayValue(double)));

connect(ui->customPlot, SIGNAL(valueChanged(double)), ui->customPlot->graph(0),SLOT(valueChanged(double));

PLS suggest how to do this

Jake007

Did you take a look at "this":http://doc.qt.digia.com/qt/signalsandslots.html tutorial?

You can connect only object which derive from QObject ( Since Qt5 if I know correctly it does no longer need to be QObject).

but correct syntax:
@connect(ui->doubleSpinBox, SIGNAL(valueChanged(double)), receiver, SLOT(methodName(double)));@

Receiver can be this if your working in the same class (QMainWindow probably).
When value in spin box is changed, it will be "sent" to you method. From there you can do further processing.

ashokkalbhor

thanks for reply
but what will come on the place of methodName() if i have to make a slot method myself because spinbox do not have any such methods

[quote author="Jake007" date="1356776769"]Did you take a look at "this":http://doc.qt.digia.com/qt/signalsandslots.html tutorial?

You can connect only object which derive from QObject ( Since Qt5 if I know correctly it does no longer need to be QObject).

but correct syntax:
@connect(ui->doubleSpinBox, SIGNAL(valueChanged(double)), receiver, SLOT(methodName(double)));@

Receiver can be this if your working in the same class (QMainWindow probably).
When value in spin box is changed, it will be "sent" to you method. From there you can do further processing. [/quote]

Jake007

Yes.

in your class
@
class MyMainWindow : QMainWindow
{
//...
public slots:
void onSpinBoxChange(double var); // make sure that arguments are the same as in the signals method.
//...
};

void MyMainWindow::onSpinBoxChange(double var)
{
// Your code to execute when value is changed.
}
@

ashokkalbhor

thanks a lot.

[quote author="Jake007" date="1356777920"]Yes.

in your class
@
class MyMainWindow : QMainWindow
{
//...
public slots:
void onSpinBoxChange(double var); // make sure that arguments are the same as in the signals method.
//...
};

void MyMainWindow::onSpinBoxChange(double var)
{
// Your code to execute when value is changed.
}
@[/quote]