why doesn't the button work?

Hi, i've created a widget with a button and a spinBox, i want to set a value in the spinBox when i'm going to click on the button. Down here the code.

ui_spinForm.h --> created with QT Designer

Code:

---

#ifndef UI_SPINFORM_H
#define UI_SPINFORM_H
 
#include <QtCore/QVariant>
#include <QtGui/QAction>
#include <QtGui/QApplication>
#include <QtGui/QButtonGroup>
#include <QtGui/QHBoxLayout>
#include <QtGui/QPushButton>
#include <QtGui/QSpinBox>
#include <QtGui/QWidget>
 
class Ui_spinForm
{
public:
    QWidget *widget;
    QHBoxLayout *hboxLayout;
    QSpinBox *spinBox;
    QPushButton *addPushButton;
 
    void setupUi(QWidget *spinForm)
    {
    if (spinForm->objectName().isEmpty())
        spinForm->setObjectName(QString::fromUtf8("spinForm"));
    spinForm->resize(258, 52);
    widget = new QWidget(spinForm);
    widget->setObjectName(QString::fromUtf8("widget"));
    widget->setGeometry(QRect(60, 10, 133, 29));
    hboxLayout = new QHBoxLayout(widget);
    hboxLayout->setObjectName(QString::fromUtf8("hboxLayout"));
    hboxLayout->setContentsMargins(0, 0, 0, 0);
    spinBox = new QSpinBox(widget);
    spinBox->setObjectName(QString::fromUtf8("spinBox"));
 
    hboxLayout->addWidget(spinBox);
 
    addPushButton = new QPushButton(widget);
    addPushButton->setObjectName(QString::fromUtf8("addPushButton"));
 
    hboxLayout->addWidget(addPushButton);
 
 
    retranslateUi(spinForm);
 
    QMetaObject::connectSlotsByName(spinForm);
    } // setupUi
 
    void retranslateUi(QWidget *spinForm)
    {
    spinForm->setWindowTitle(QApplication::translate("spinForm", "Try a spinbox", 0, QApplication::UnicodeUTF8));
    addPushButton->setText(QApplication::translate("spinForm", "Add", 0, QApplication::UnicodeUTF8));
    Q_UNUSED(spinForm);
    } // retranslateUi
 
};
 
namespace Ui {
    class spinForm: public Ui_spinForm {};
} // namespace Ui
 
#endif // UI_SPINFORM_H

---

spinForm.h

Code:

---

#include "ui_spinForm.h"
 
class spinForm : public QWidget, public Ui::spinForm
{
	Q_OBJECT
 
public:
	spinForm(QWidget *parent = 0);
 
private slots:
	void setSpinBoxValue();
 
private:
	Ui::spinForm ui;
};

---

spinForm.cpp

Code:

---

#include <QtGui>
#include "spinForm.h"
 
spinForm::spinForm(QWidget *parent):QWidget(parent)
{
	connect(addPushButton, SIGNAL(clicked()), this, SLOT(setSpinBoxValue()));
	ui.setupUi(this);
}
 
void spinForm::setSpinBoxValue()
{
	spinBox->setValue(45);
}

---

main.cpp

Code:

---

#include <QApplication>
 
#include "ui_spinForm.h"
 
int main(int argc, char *argv[])
{
	QApplication app(argc, argv);
	QWidget *widget = new QWidget;
	Ui::spinForm ui;
	ui.setupUi(widget);
	widget->show();
	return app.exec();
}

---

When i compile it i don't have any problems, i can lunch the widget but when i click on the button nothing happen.
I've tried to put spinBox->setValue(45) in the constructor too...
I've checked the code a lot of time but i haven't catch any errors, maybe cos i'm a newbie!
Thanks ppl for your support ;)

First, you are mixing aproaches.
Either use the 'ui' as member OR derive it.
I recommend using it as member - more flexible.
Try:

Code:

---

#include "ui_spinForm.h"
 
      class spinForm : public QWidget
      {
          Q_OBJECT
      public:
          spinForm(QWidget *parent = 0);
      private slots:
          void setSpinBoxValue();
      private:
          Ui::spinForm ui;
      };

---

Code:

---

#include <QtGui>
      #include "spinForm.h"
 
      spinForm::spinForm(QWidget *parent):QWidget(parent)
      {
         ui.setupUi(this);  
        connect(ui.addPushButton, SIGNAL(clicked()), this, SLOT(setSpinBoxValue()));
 
      }
 
      void spinForm::setSpinBoxValue()
       {
           ui.spinBox->setValue(45);
 
      }

---

I did it, and I realized that i was mixing aproaches.
I don't have any errors when i compile the project, but the button doesn't work...thx

run it from a console, and see if you are getting any warnings

This is the output from my make command:

Code:

---

$make:
g++ -c -pipe -O2 -Wall -W -D_REENTRANT -DQT_NO_DEBUG -DQT_GUI_LIB -DQT_CORE_LIB -DQT_SHARED -I/usr/local/Trolltech/Qt-4.3.1/mkspecs/linux-g++ -I. -I/usr/local/Trolltech/Qt-4.3.1/include/QtCore -I/usr/local/Trolltech/Qt-4.3.1/include/QtCore -I/usr/local/Trolltech/Qt-4.3.1/include/QtGui -I/usr/local/Trolltech/Qt-4.3.1/include/QtGui -I/usr/local/Trolltech/Qt-4.3.1/include -I. -I. -I. -o main.o main.cpp
g++ -Wl,-rpath,/usr/local/Trolltech/Qt-4.3.1/lib -o spinForm main.o spinForm.o moc_spinForm.o    -L/usr/local/Trolltech/Qt-4.3.1/lib -lQtGui -L/usr/local/Trolltech/Qt-4.3.1/lib -L/usr/X11R6/lib -lpng -lSM -lICE -pthread -pthread -lXi -lXrender -lXrandr -lXfixes -lXcursor -lXinerama -lfreetype -lfontconfig -lXext -lX11 -lQtCore -lz -lm -pthread -lgthread-2.0 -lglib-2.0 -lrt -ldl -lpthread

---

and i attach my .pro file too:

Code:

---

TEMPLATE = app
TARGET = 
DEPENDPATH += .
INCLUDEPATH += .
 
# Input
HEADERS += spinForm.h
FORMS += spinForm.ui
SOURCES += main.cpp spinForm.cpp

---

try changing setSpinBoxValue() from private slot to public slot!

what hgedek said is correct.
And I didn't ask for compilation output but that you RUN the program in a console.

i've changed it to public but i have some error:

Code:

---

spinForm.cpp: In constructor ‘spinForm::spinForm(QWidget*)’:
spinForm.cpp:9: error: ‘addPushButton’ was not declared in this scope
spinForm.cpp: In member function ‘void spinForm::setSpinBoxValue()’:
spinForm.cpp:15: error: ‘spinBox’ was not declared in this scope
make: *** [spinForm.o] Error 1

---

Quote:

---

Originally Posted by mattia

i've changed it to public but i have some error:

Code:

---

spinForm.cpp: In constructor ‘spinForm::spinForm(QWidget*)’:
spinForm.cpp:9: error: ‘addPushButton’ was not declared in this scope
spinForm.cpp: In member function ‘void spinForm::setSpinBoxValue()’:
spinForm.cpp:15: error: ‘spinBox’ was not declared in this scope
make: *** [spinForm.o] Error 1

---

---

Actually, it doesn't matter whether it's public or not. That only affects the visibility when the slot is called as a normal function. However, looks like you still have mixed up "single inheritance" and "multiple inheritance" approaches. Take a closer look at second post in this thread.

yes, you are right, I had omit the ui. before the object declered into ui_spinForm.h.
Now i've added them but i can't set any value into the spinBox, maybe i've to set the range?

I've added into Ui_spinForm.h a spinBox->setValue(5); and when i start the widget the value is 5. I've added ui.spinBox->setValue(5); into the spinForm.cpp constructor

Code:

---

spinForm::spinForm(QWidget *parent):QWidget(parent)
{
	ui.setupUi(this);
	connect(ui.addPushButton, SIGNAL(clicked()), this, SLOT(setSpinBoxValue()));
	ui.spinBox->setValue(3);
}

---

but nothing...

mmm...i added a textBrowser to see if it works, but in the spinForm.cpp i can't add any text, no errors, but it doesn't work....:crying:

post your full code, and run the application in a console and see if you get any warnings.

ui_spinForm.h

Code:

---

#ifndef UI_SPINFORM_H
#define UI_SPINFORM_H
 
#include <QtCore/QVariant>
#include <QtGui/QAction>
#include <QtGui/QApplication>
#include <QtGui/QButtonGroup>
#include <QtGui/QHBoxLayout>
#include <QtGui/QPushButton>
#include <QtGui/QSpinBox>
#include <QtGui/QTextBrowser>
#include <QtGui/QWidget>
 
class Ui_spinForm
{
public:
    QWidget *layoutWidget;
    QHBoxLayout *hboxLayout;
    QSpinBox *spinBox;
    QPushButton *addPushButton;
    QTextBrowser *textBrowser;
 
    void setupUi(QWidget *spinForm)
    {
    if (spinForm->objectName().isEmpty())
        spinForm->setObjectName(QString::fromUtf8("spinForm"));
    spinForm->resize(359, 370);
    layoutWidget = new QWidget(spinForm);
    layoutWidget->setObjectName(QString::fromUtf8("layoutWidget"));
    layoutWidget->setGeometry(QRect(60, 10, 133, 29));
    hboxLayout = new QHBoxLayout(layoutWidget);
    hboxLayout->setObjectName(QString::fromUtf8("hboxLayout"));
    hboxLayout->setContentsMargins(0, 0, 0, 0);
    spinBox = new QSpinBox(layoutWidget);
    spinBox->setObjectName(QString::fromUtf8("spinBox"));
    spinBox->setValue(5);
 
    hboxLayout->addWidget(spinBox);
 
    addPushButton = new QPushButton(layoutWidget);
    addPushButton->setObjectName(QString::fromUtf8("addPushButton"));
 
    hboxLayout->addWidget(addPushButton);
 
    textBrowser = new QTextBrowser(spinForm);
    textBrowser->setObjectName(QString::fromUtf8("textBrowser"));
    textBrowser->setGeometry(QRect(40, 70, 256, 192));
 
    retranslateUi(spinForm);
 
    QMetaObject::connectSlotsByName(spinForm);
    } // setupUi
 
    void retranslateUi(QWidget *spinForm)
    {
    spinForm->setWindowTitle(QApplication::translate("spinForm", "Try a spinbox", 0, QApplication::UnicodeUTF8));
    addPushButton->setText(QApplication::translate("spinForm", "Add", 0, QApplication::UnicodeUTF8));
 
    Q_UNUSED(spinForm);
    } // retranslateUi
 
};
 
namespace Ui {
    class spinForm: public Ui_spinForm {};
} // namespace Ui
 
#endif // UI_SPINFORM_H

---

spinForm.h

Code:

---

#include "ui_spinForm.h"
 
class spinForm : public QWidget
{
	Q_OBJECT
 
public:
	spinForm(QWidget *parent = 0);
 
public slots:
	void setSpinBoxValue();
 
private:
	Ui::spinForm ui;
};

---

spinForm.cpp

Code:

---

#include <QtGui>
#include "spinForm.h"
 
spinForm::spinForm(QWidget *parent):QWidget(parent)
{
	ui.setupUi(this);
	connect(ui.addPushButton, SIGNAL(clicked()), this, SLOT(setSpinBoxValue()));
	ui.spinBox->setValue(3);
 
}
 
void spinForm::setSpinBoxValue()
{
	ui.spinBox->setValue(45);
}

---

main.cpp

Code:

---

#include <QApplication>
 
#include "ui_spinForm.h"
 
int main(int argc, char *argv[])
{
	QApplication app(argc, argv);
	QWidget *widget = new QWidget;
	Ui::spinForm ui;
	ui.setupUi(widget);
	widget->show();
	return app.exec();
}

---

what can i do to run it in a consolle? is it helpful to see the run-time error?
cos now i'm using QT Designer and a simple text editor.
Thanks

I imported the project into Eclipse with QT library plug-in but when i make to run the application nothing is shown in consolle.

In your main() you instantiate Ui::spinform not your own class spinform.
Your code is never executed -> that's why you don't see anything!

Quote:

---

Originally Posted by DeepDiver

In your main() you instantiate Ui::spinform not your own class spinform.
Your code is never executed -> that's why you don't see anything!

---

Thanks for the hint, i've chenged my main.cpp in this way:

Code:

---

#include <QApplication>
 
#include "spinForm.h"
 
int main(int argc, char *argv[])
{
	QApplication app(argc, argv);
	QWidget *widget = new QWidget;
	spinForm ui(widget);
	//ui.setupUi(widget);
	widget->show();
	return app.exec();
}

---

and now it run, thanks to everybody...it was my first program with a slot and signal ;)

Quote:

---

Originally Posted by high_flyer

First, you are mixing aproaches.
Either use the 'ui' as member OR derive it.
I recommend using it as member - more flexible.

---

I'd like to know how's the derive approach, are there any examples on the net?
Thanks

Its all in the docs.
Note that you can use the single or multiple inheritance approaches, see what best fits your case.