how connection variable in functin with spinBox

[Sergey19]

I read documentation....and write next code .but I have a mistale
View code:

void DataPlot::strob(Qt::Orientation o,
    const QColor &c, double base)
{
    QSpinBox*spinBox2 = new QSpinBox;
    spinBox2->setRange(0,699);
   // spinBox2->setValue(43);
    spinBox2->show();
    double i = spinBox2->value();
    QObject::connect(spinBox2,SIGNAL(valueChanged(int)),i,SLOT(value));
    QwtPlotCurve *curve = new QwtPlotCurve();
  curve->setPen(QPen(Qt::blue,3));
   //  double i ;
    double x[10];
    double y[sizeof(x) / sizeof(x[0])];
 
    for ( uint k = 0; k < sizeof(x) / sizeof(x[0]); k++ )
    {
 
        double v = i+k * 1.5;
        if ( o == Qt::Horizontal )
        {
            x[k] = v;
            y[k] = base;
        }
        else
        {
            x[k] = base;
            y[k] = v;
        }
    }
    curve->setData(x, y, sizeof(x) / sizeof(x[0]));
    curve->attach(this);
}

void DataPlot::strob(Qt::Orientation o,
    const QColor &c, double base)
{
    QSpinBox*spinBox2 = new QSpinBox;
    spinBox2->setRange(0,699);
   // spinBox2->setValue(43);
    spinBox2->show();
    double i = spinBox2->value();
    QObject::connect(spinBox2,SIGNAL(valueChanged(int)),i,SLOT(value));
    QwtPlotCurve *curve = new QwtPlotCurve();
  curve->setPen(QPen(Qt::blue,3));
   //  double i ;
    double x[10];
    double y[sizeof(x) / sizeof(x[0])];

    for ( uint k = 0; k < sizeof(x) / sizeof(x[0]); k++ )
    {
       
        double v = i+k * 1.5;
        if ( o == Qt::Horizontal )
        {
            x[k] = v;
            y[k] = base;
        }
        else
        {
            x[k] = base;
            y[k] = v;
        }
    }
    curve->setData(x, y, sizeof(x) / sizeof(x[0]));
    curve->attach(this);
}

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[Lykurg]

Obviously you don't have read the documentation carefully! First you really should use layouts, and further, i is no object its a integer which you cant use in a connect statement as a receiver!

If you want to redraw your function when the value of i changes make three functions: the first sets up the ui (only one time), next is a slot you call when your spinbox changes, and a third is your paint function depending on your local variable i. You also can combine the 2nd and 3rd function by skiping the local variable and using spinBox2->value() directly in the slot. But rally first set up your gui and don't do it all in one function because that won't work.

[Sergey19]

what mean ui !? I don't understand what function you mean.I understand that first is change spinbox and what about others !?

[Lykurg]

How should

QObject::connect(spinBox2,SIGNAL(valueChanged(int)),i,SLOT(value));

QObject::connect(spinBox2,SIGNAL(valueChanged(int)),i,SLOT(value));

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work, if i is a double? the receiver in a connect statement has to be a QObject. (As it is written in the documentation!)

[Sergey19]

I understand this ,but I don't know what receiver I must have in this connect )

[Lykurg]

Any QObject derived class with a proper slot! And in your situation nothing will fit since your design is...

[Sergey19]

Help me create slot .Thank you very much ))

[sherbs]

As others have mentioned, you need to spend some time doing your homework:

http://doc.trolltech.com/4.6/signalsandslots.html

Read through this documentation and you should easily be able to accomplish what you want to do... As of now, your design/code reflects a fairly fundamental misunderstanding of how Qt works.

It will be very difficult to help you otherwise.

[Zlatomir]

Isn't it better to put the 'i' variable in the class definition? (not a local variable to that function)
And declare a function (a slot, with "public slots:" access specifier) and that function will look like:

void  YourClass::set_i(double input) { i = input;} //i is your member variable i

void  YourClass::set_i(double input) { i = input;} //i is your member variable i

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and connect this slot with the SpinBox valueChanged signal:
(in your class constructor if the spinbox2 is member of the same class!)

connect(spinBox2,SIGNAL(valueChanged(double)), this, SLOT(set_i(double));

connect(spinBox2,SIGNAL(valueChanged(double)), this, SLOT(set_i(double));

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Note: You can do it with double or int, but the QSpinBox doesn't have a valueChanged(double) only int
QDoubleSpinBox has valueChanged(double) not int

And we can't create a complete design, we can only give you advices, because we don't know the actual problem (don't even know the design of your class)

[Sergey19]

Isn't it better to put the 'i' variable in the class definition? (not a local variable to that function)
And declare a function (a slot, with "public slots:" access specifier) and that function will look like:

void  YourClass::set_i(double input) { i = input;} //i is your member variable i

void  YourClass::set_i(double input) { i = input;} //i is your member variable i

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and connect this slot with the SpinBox valueChanged signal:
(in your class constructor if the spinbox2 is member of the same class!)

connect(spinBox2,SIGNAL(valueChanged(double)), this, SLOT(set_i(double));

connect(spinBox2,SIGNAL(valueChanged(double)), this, SLOT(set_i(double));

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Note: You can do it with double or int, but the QSpinBox doesn't have a valueChanged(double) only int
QDoubleSpinBox has valueChanged(double) not int

And we can't create a complete design, we can only give you advices, because we don't know the actual problem (don't even know the design of your class)

I create a line ....And I want when user change value in spinBox this line move left or right .