No Appropriate Default Constructor -- Help Please??

AngelMacias

Hello QtProject again,

I've been posting here for the past month now as I have been working on a school project for the last month asking for help(which I greatly appreciate the help from you fine folk). Anyways, to the error:

@error: C2512: 'Ui::GuiDialog' : no appropriate default constructor available

error: C1903: unable to recover from previous error(s); stopping compilation@

Here is my header file and snippet of my code:

GuiDialog.h
@#ifndef GUIDIALOG_H
#define GUIDIALOG_H

#include <QObject>
#include <QtGui>
#include <QDialog>
#include <QLabel>
#include "Dealer.h"
#include "Player.h"
#include "GameModel.h"

namespace Ui
{
class GuiDialog;
}

class GuiDialog: public QDialog
{
Q_OBJECT

public:
GuiDialog(QWidget *parent=0);
GuiDialog(QWidget *, GameModel *);
~GuiDialog();
public slots:
void updateCard(int, int);
void newScore(int);
void endGame();
void playerWon();
void dealerWon();
void tie();
void updatePlayerThirdCard();
void updateDealerThirdCard();
private:
GameModel *model;
Ui::GuiDialog *ui;
QLabel *playerCards, *dealerCards, *displayWinner;
QPushButton *betButton;
QLCDNumber *number;
int score;

};

#endif // GUIDIALOG_H@

GuiDialog.cpp
@#include "GuiDialog.h"
#include "GameModel.h"
#include <QDialog>
#include <QtGui>
#include <QPixmap>
#include <QLabel>
#include <QtGlobal>

/*****************************************
/* This class will implement the changes
/* taking place in the GUI such as updating
/* the cards being displayed
/*****************************************/

GuiDialog::GuiDialog(QWidget *parent) : QDialog(parent), ui(new Ui::GuiDialog) //<----error takes me to this line
{
ui->setupUi(this);
}

GuiDialog::GuiDialog(QWidget *parent, GameModel *model): QDialog(parent), ui(new Ui::GuiDialog)
{
betButton = new QPushButton(tr("&Bet"));

QSpinBox *spinBox = new QSpinBox;
QSlider *slider = new QSlider(Qt::Horizontal);
spinBox->setRange(0, 100000);
slider->setRange(0, 100000);

QObject::connect(spinBox, SIGNAL(valueChanged(int)),
                 slider, SLOT(setValue(int)));
QObject::connect(slider, SIGNAL(valueChanged(int)),
                 spinBox, SLOT(setValue(int)));

/**/@

I've searched at the Qt-Project forums for help as well as google for solutions. Sadly, I could not really find anything here and google only showed me results of C++ programs not involving Qt. I understand that the compiler is not reading my default constructor that's why it refuses to compile, but I thought that first set of lines in GuiDialog.cpp(where the error takes me) is the default constructor? Granted, I am a student barely learning this and I merely copied the syntax of brand new "MainWindow" project in hopes that it would work. But apart from that, I really want to know what constitutes a default constructor such that the first lines of my GuiDialog.cpp do not make it the default constructor as I thought it would be?

Thank you for your help and time.

Code_ReaQtor

This code at line 23 of GuiDialog.h seems like incomplete
@GuiDialog(QWidget *, GameModel *);@

try to change it this way:
@GuiDialog(QWidget *parent, GameModel *model);@

MuldeR

Code_ReaQtor, I think it is okay to leave out the argument names in the declaration.

AngelMacias, the error message would indicate that Ui::GuiDialog has no appropriate default constructor. But it seems you nowhere include the header file where that class is declared! Sure, in your GuiDialog.h you have a forward declaration of Ui::GuiDialog, but an actual declaration is missing! Which explains why that class cannot be instantiated! Normally you would have a Qt Designer .ui file that you compile with the "UIC":http://doc.qt.digia.com/qt/uic.html in order to generate the header .h file with the declaration of Ui::GuiDialog. This you would then include in your GuiDialog.cpp file, in addition to your own hand-written .h file! Note that GuiDialog and Ui::GuiDialog are two separate classes. The former is your own class, the latter is the class generated by Qt Designer/UIC.

Have a look here:
http://doc.qt.digia.com/qt/designer-using-a-ui-file.html

BTW: What you are using is "The Single Inheritance Approach" with "Using a Pointer Member Variable".

AngelMacias

I found what you were referring to MuldeR.

@/********************************************************************************
** Form generated from reading UI file 'GuiDialog.ui'
**
** Created: Fri Dec 7 16:13:14 2012
** by: Qt User Interface Compiler version 4.8.1
**
** WARNING! All changes made in this file will be lost when recompiling UI file!
********************************************************************************/

#ifndef UI_GUIDIALOG_H
#define UI_GUIDIALOG_H

#include <QtCore/QVariant>
#include <QtGui/QAction>
#include <QtGui/QApplication>
#include <QtGui/QButtonGroup>
#include <QtGui/QDialog>
#include <QtGui/QHeaderView>
#include <QtGui/QLCDNumber>
#include <QtGui/QLabel>
#include <QtGui/QPushButton>
#include <QtGui/QSlider>
#include <QtGui/QSpinBox>

QT_BEGIN_NAMESPACE

class Ui_Dialog
{
public:
QSlider *slider;
QSpinBox *spinBox;
QPushButton *betButton;
QLCDNumber *number;
QLabel *playerCards;

void setupUi(QDialog *Dialog)
{
    if (Dialog->objectName().isEmpty())
        Dialog->setObjectName(QString::fromUtf8("Dialog"));
    Dialog->resize(779, 462);
    Dialog->setStyleSheet(QString::fromUtf8("GuiDialog { background-image: url(:/images/table.png) };"));
    slider = new QSlider(Dialog);
    slider->setObjectName(QString::fromUtf8("slider"));
    slider->setGeometry(QRect(200, 400, 491, 21));
    slider->setOrientation(Qt::Horizontal);
    spinBox = new QSpinBox(Dialog);
    spinBox->setObjectName(QString::fromUtf8("spinBox"));
    spinBox->setGeometry(QRect(120, 400, 61, 22));
    betButton = new QPushButton(Dialog);
    betButton->setObjectName(QString::fromUtf8("betButton"));
    betButton->setGeometry(QRect(330, 360, 91, 31));
    number = new QLCDNumber(Dialog);
    number->setObjectName(QString::fromUtf8("number"));
    number->setGeometry(QRect(100, 350, 91, 41));
    number->setFrameShadow(QFrame::Sunken);
    number->setDigitCount(5);
    number->setProperty("intValue", QVariant(500));
    playerCards = new QLabel(Dialog);
    playerCards->setObjectName(QString::fromUtf8("playerCards"));
    playerCards->setGeometry(QRect(220, 190, 351, 131));
    playerCards->setPixmap(QPixmap(QString::fromUtf8(":/cards/Cards/back.jpg")));

    retranslateUi(Dialog);
    QObject::connect(spinBox, SIGNAL(valueChanged(int)), slider, SLOT(setValue(int)));
    QObject::connect(slider, SIGNAL(valueChanged(int)), spinBox, SLOT(setValue(int)));

    QMetaObject::connectSlotsByName(Dialog);
} // setupUi

void retranslateUi(QDialog *Dialog)
{
    Dialog->setWindowTitle(QApplication::translate("Dialog", "Dialog", 0, QApplication::UnicodeUTF8));
    betButton->setText(QApplication::translate("Dialog", "Bet", 0, QApplication::UnicodeUTF8));
    playerCards->setText(QString());
} // retranslateUi

};

namespace Ui {
class Dialog: public Ui_Dialog {};
} // namespace Ui

QT_END_NAMESPACE

#endif // UI_GUIDIALOG_H@

So I tried doing this...

@namespace Ui {
class Dialog: public Ui_Dialog {};

class GuiDialog : public Ui_Dialog { };

}@

The compiler did not give me any errors regarding the constructor anymore, but I just want to make sure I'm doing it right.

MuldeR

I cannot follow your code... ???

Normally your header file (.h), the one you write yourself, looks like:
@#ifndef GUIDIALOG_H
#define GUIDIALOG_H

/* more includes you may need */

//Forward declaration of Ui::GuiDialog
namespace Ui
{
class GuiDialog;
}

//Your own class that uses the Ui::GuiDialog class
class GuiDialog: public QDialog
{
Q_OBJECT

public:
GuiDialog(QWidget *, GameModel *);
~GuiDialog();

/* ..... */

private:
Ui::GuiDialog *ui; //Pointer member-variable for GUI

/* ..... */

};

#endif // GUIDIALOG_H@

And in your code file (.cpp) you would do:
@#include "GuiDialog.h" //Your own header file from above
#include "UIC_GuiDialog.h" //The header generated by the UIC (for Ui::GuiDialog)

/* more includes you may need */

//Constructor
GuiDialog::GuiDialog(QWidget *parent, GameModel *model) :
QDialog(parent), ui(new Ui::GuiDialog)
{
ui->setupUi(this);
}

//Destructor
GuiDialog::~GuiDialog(void)
{
delete ui;
}

/* ........... */
@

And remember: Never try to edit the .h file that UIC has generated. Your changes would be lost at the next re-compile. UIC re-generates the .h file from the .ui file. Just use the UIC-generated .h file as it pops out of UIC.

Also: In the above code I assumed the UIC-generated file is at "UIC_GuiDialog.h". Adjust that path as required!

PROuC

Hello MuldeR,

due to the topic i get the same error C2512 by using Ui::SettingsDialog in combination with QSerialPort terminal example.

I am using Qt 4.8.4 and could compile the master blocking example, so i guess that i install QSerialPort right. Do you have an idea or hint whats wrong?
@
#ifndef SETTINGSDIALOG_H
#define SETTINGSDIALOG_H
#include <QDialog>
#include <QSettings>
#include <QtSerialPort/QSerialPort>
QT_USE_NAMESPACE
namespace Ui {
class SettingsDialog;
}
class QIntValidator;
class SettingsDialog : public QDialog
{
Q_OBJECT

public:
struct Settings {
QString name;
qint32 baudRate;
QString stringBaudRate;
QSerialPort::DataBits dataBits;
QString stringDataBits;
QSerialPort::Parity parity;
QString stringParity;
QSerialPort::StopBits stopBits;
QString stringStopBits;
QSerialPort::FlowControl flowControl;
QString stringFlowControl;
bool localEchoEnabled;
};

SettingsDialog(QWidget *parent = 0);  //explicit
~SettingsDialog();

Settings settings() const;

private slots:
void showPortInfo(int idx);
void apply();
void checkCustomBaudRatePolicy(int idx);

private:
void fillPortsParameters();
void fillPortsInfo();
void updateSettings();

private:
Ui::SettingsDialog *ui;
Settings currentSettings;
QIntValidator *intValidator;
};

#endif // SETTINGSDIALOG_H
@

@#include "settingsdialog.h"
#include "ui_settingsdialog.h"

#include <QtSerialPort/QSerialPortInfo>
#include <QIntValidator>
#include <QLineEdit>

QT_USE_NAMESPACE

SettingsDialog::SettingsDialog(QWidget *parent) :
QDialog(parent),
ui(new Ui::SettingsDialog) // here C2512
{
ui->setupUi(this);

intValidator = new QIntValidator(0, 4000000, this);

ui->baudRateBox->setInsertPolicy(QComboBox::NoInsert);

connect(ui->applyButton, SIGNAL(clicked()),
        this, SLOT(apply()));
connect(ui->serialPortInfoListBox, SIGNAL(currentIndexChanged(int)),
        this, SLOT(showPortInfo(int)));
connect(ui->baudRateBox, SIGNAL(currentIndexChanged(int)),
        this, SLOT(checkCustomBaudRatePolicy(int)));

fillPortsParameters();
fillPortsInfo();

updateSettings();

}

SettingsDialog::~SettingsDialog()
{
delete ui;
}

SettingsDialog::Settings SettingsDialog::settings() const
{
return currentSettings;
}
// continued
//
}@

Thank you for your help.

MuldeR

Check your "ui_settingsdialog.h" file, which I assume was generated by UIC.

Is the file in place? And does it really define a class Ui::SettingsDialog? If so, how does the constructor of that class look?

PROuC

Hello MuldeR,

u assumed right, it was not generatet the ui_settingsdialog.h. I changed the constructor name to Dialog and did not changed the class name into the dialog.ui. It works great now.

@
<?xml version="1.0" encoding="UTF-8"?>
<ui version="4.0">
<class>Dialog</class> // here
<widget class="QDialog" name="Dialog">
<property name="geometry">
@

Thank you for your reply. It is going more and more clear for me.

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No Appropriate Default Constructor -- Help Please??