Access variables of other classes

[przemek]

Hello, I have some problem - I cannot use a variable from other class.
For example I have in class Setts QSpinBox SB1 and int i. I would like to check value of 'i' and set value of SB1 in method in class Pac.
I tried Setts::set_ui->SB1->setValue(1); but I got error: object missing in reference to 'Setts::set_ui'

setts.h

#include <QSpinBox>
#include "ui_setts.h>
 
namespace Ui {
    class Setts;
}
 
class Setts : public QDialog {
    Q_OBJECT
public:
    Setts(QWidget *parent = 0);
    ~Setts();
   Ui::Setts *set_ui;
 
protected:
    void changeEvent(QEvent *e);
 
private:
   QSpinBox *SB1;
   int i;
}

#include <QSpinBox>
#include "ui_setts.h>

namespace Ui {
    class Setts;
}

class Setts : public QDialog {
    Q_OBJECT
public:
    Setts(QWidget *parent = 0);
    ~Setts();
   Ui::Setts *set_ui;

protected:
    void changeEvent(QEvent *e);

private:
   QSpinBox *SB1;
   int i;
}

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setts.cpp

#include "setts.h"
#include "ui_setts.h"
 
Setts::Setts(QWidget *parent) :
    QDialog(parent),
    set_ui(new Ui::Setts)
 
{
    set_ui->setupUi(this);
    this->showFullScreen();
}

#include "setts.h"
#include "ui_setts.h"

Setts::Setts(QWidget *parent) :
    QDialog(parent),
    set_ui(new Ui::Setts)

{
    set_ui->setupUi(this);
    this->showFullScreen();
}

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Thanks in advanced
Przemek

[Diath]

What about moving variables from private to public? :P

[przemek]

I tried, without results

[Lykurg]

Use getter and setter methods. Also search the forum, there are hundreds post of that topic.

[przemek]

Thanks Lykurg, but I have question. Is it alone way to use getter and setter methods? Is not possible to access variable without extra methods?

[Zlatomir]

That is the reason why you declared your variables with "private" access specifier, so they can't be accessed/modified directly, only by their "public" getter/setter functions.

LE: also notice that: Setts::set_ui->SB1->setValue(1); //most likely you tried that before constructing the actual object, set_ui is only a pointer... you construct your UI object in your class constructor... something like... set_ui = new UI_Class_Name(most likely 'this' as a parent); only after that you can do "stuff" to the UI pointer.

When you use pointers you <need to> have two(2) objects, the pointer and the actual object that is "pointed to".

[Zlatomir]

Sorry for double post... I edited (corrected) the last one a little bit, and a little advice

Most likely, the setter functions you will want(need) to declare as slots, so that you can connect (other objects) signals to them.

[tbscope]

You can also use events or signals and slots.

[Zlatomir]

I attached the sample project (as i promised )

I used signals and slots and created some signals and slots for keeping the ui pointers private (you can do that, or you can inherit from both the ui_generated class and QDialog, QMainWindow or QWidget) i like (and use most) the private pointer member and code what signals and slots i need.VariablesUpdate.zip