Accessing widgets from my class

Flurite · wrote on 24 Apr 2012, 01:22

Sorry I'm probably being really dumb right now.

Anyway, I read it, but I am not understanding how this will help me. The header file that contains the code you said previously is called clock_application.h

MuldeR · wrote on 24 Apr 2012, 01:28

Well, did you manage to locate the header file generated by UIC?

If so, did you inspect that file to make sure it contains a definition of Ui::Clock_Application ???

In your code you use the Ui::Clock_Application class (note hat that is one is different from the Clock_Application class without the "Ui::"). This requires that this class is defined somewhere. Your error message indicates that you have a forward-declaration of that class, but no definition of it! A forward-declaration is sufficient to declare the pointer member variable in your own class, but as soon as you want to dereference the pointer, a full definition is required. That definition usually is given in the header file generated by UIC (from your .UI file).

Flurite · wrote on 24 Apr 2012, 01:34

Aha, I found it! I just recalled there are two folders for a project! Let me copy and paste the code for you. It's a long piece.

@
/********************************************************************************
** Form generated from reading UI file 'clock_application.ui'
**
** Created: Sat Mar 17 18:50:58 2012
** by: Qt User Interface Compiler version 4.7.4
**
** WARNING! All changes made in this file will be lost when recompiling UI file!
********************************************************************************/

#ifndef UI_CLOCK_APPLICATION_H
#define UI_CLOCK_APPLICATION_H

#include <QtCore/QVariant>
#include <QtGui/QAction>
#include <QtGui/QApplication>
#include <QtGui/QButtonGroup>
#include <QtGui/QHeaderView>
#include <QtGui/QLineEdit>
#include <QtGui/QMainWindow>
#include <QtGui/QPushButton>
#include <QtGui/QStatusBar>
#include <QtGui/QTabWidget>
#include <QtGui/QToolBar>
#include <QtGui/QWidget>

QT_BEGIN_NAMESPACE

class Ui_Clock_Application
{
public:
QWidget *centralWidget;
QTabWidget *ClockSet;
QWidget *Stopwatch;
QLineEdit *Output;
QPushButton *Start;
QPushButton *Pause;
QPushButton *Reset;
QWidget *Alarm;
QToolBar *mainToolBar;
QStatusBar *statusBar;

void setupUi(QMainWindow *Clock_Application)
{
    if (Clock_Application->objectName().isEmpty())
        Clock_Application->setObjectName(QString::fromUtf8("Clock_Application"));
    Clock_Application->resize(400, 300);
    centralWidget = new QWidget(Clock_Application);
    centralWidget->setObjectName(QString::fromUtf8("centralWidget"));
    ClockSet = new QTabWidget(centralWidget);
    ClockSet->setObjectName(QString::fromUtf8("ClockSet"));
    ClockSet->setGeometry(QRect(10, 0, 371, 241));
    ClockSet->setTabPosition(QTabWidget::North);
    ClockSet->setTabShape(QTabWidget::Rounded);
    Stopwatch = new QWidget();
    Stopwatch->setObjectName(QString::fromUtf8("Stopwatch"));
    Output = new QLineEdit(Stopwatch);
    Output->setObjectName(QString::fromUtf8("Output"));
    Output->setGeometry(QRect(120, 50, 131, 31));
    Output->setAlignment(Qt::AlignCenter);
    Start = new QPushButton(Stopwatch);
    Start->setObjectName(QString::fromUtf8("Start"));
    Start->setGeometry(QRect(40, 110, 81, 31));
    Pause = new QPushButton(Stopwatch);
    Pause->setObjectName(QString::fromUtf8("Pause"));
    Pause->setGeometry(QRect(150, 110, 81, 31));
    Reset = new QPushButton(Stopwatch);
    Reset->setObjectName(QString::fromUtf8("Reset"));
    Reset->setGeometry(QRect(250, 110, 81, 31));
    ClockSet->addTab(Stopwatch, QString());
    Alarm = new QWidget();
    Alarm->setObjectName(QString::fromUtf8("Alarm"));
    ClockSet->addTab(Alarm, QString());
    Clock_Application->setCentralWidget(centralWidget);
    mainToolBar = new QToolBar(Clock_Application);
    mainToolBar->setObjectName(QString::fromUtf8("mainToolBar"));
    Clock_Application->addToolBar(Qt::TopToolBarArea, mainToolBar);
    statusBar = new QStatusBar(Clock_Application);
    statusBar->setObjectName(QString::fromUtf8("statusBar"));
    Clock_Application->setStatusBar(statusBar);

    retranslateUi(Clock_Application);
    QObject::connect(Start, SIGNAL(clicked()), Clock_Application, SLOT(timer_Start()));

    ClockSet->setCurrentIndex(0);


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

void retranslateUi(QMainWindow *Clock_Application)
{
    Clock_Application->setWindowTitle(QApplication::translate("Clock_Application", "Clock_Application", 0, QApplication::UnicodeUTF8));
    Output->setText(QApplication::translate("Clock_Application", "00:00:00", 0, QApplication::UnicodeUTF8));
    Start->setText(QApplication::translate("Clock_Application", "Start", 0, QApplication::UnicodeUTF8));
    Pause->setText(QApplication::translate("Clock_Application", "Pause", 0, QApplication::UnicodeUTF8));
    Reset->setText(QApplication::translate("Clock_Application", "Reset", 0, QApplication::UnicodeUTF8));
    ClockSet->setTabText(ClockSet->indexOf(Stopwatch), QApplication::translate("Clock_Application", "Stopwatch", 0, QApplication::UnicodeUTF8));
    ClockSet->setTabText(ClockSet->indexOf(Alarm), QApplication::translate("Clock_Application", "Alarm", 0, QApplication::UnicodeUTF8));
} // retranslateUi

};

namespace Ui {
class Clock_Application: public Ui_Clock_Application {};
} // namespace Ui

QT_END_NAMESPACE

#endif // UI_CLOCK_APPLICATION_H
@

MuldeR · wrote on 24 Apr 2012, 01:39

So Ui::Clock_Application is defined (lines 103 to 105).

But then I don't understand why the compiler throws the following error:
@invalid use of incomplete struct type ‘struct Ui::Clock_Application’ @

Are you 100% sure the source code file that throws this error includes the exactly same header file you quoted?

Flurite · wrote on 24 Apr 2012, 01:45

I've had a problem like that before with mutual friendship classes. I fixed it by simply defining the functions after both classes were defined. Obviously, this is not the problem in this case..

MuldeR · wrote on 24 Apr 2012, 01:48

Time to post your complete clock_application.h and clock_application.cpp, I think.

Flurite · wrote on 24 Apr 2012, 02:15

clock_application.h:

@

#ifndef CLOCK_APPLICATION_H
#define CLOCK_APPLICATION_H

#include <QMainWindow>
#include <QTimer>
#include <QLineEdit>

namespace Ui {
class Clock_Application;
}

class Clock_Application : public QMainWindow
{
Q_OBJECT

public:
explicit Clock_Application(QWidget *parent = 0);
~Clock_Application();
public slots:
void timer_Start();
void changeTime();
private:
Ui::Clock_Application ui;
QTimer timer;
};

void Clock_Application::timer_Start()
{
timer = new QTimer();
connect(timer, SIGNAL(timeout()), this, SLOT(changeTime()));
timer->start(1000);
}

void Clock_Application::changeTime()
{
std::vector<int> times;
QRegExp findTimeSequences("(\d+)");
QString currentTime(ui->Output->text());

int posOffset(0);
while ((posOffset = findTimeSequences.indexIn(currentTime, posOffset)) != -1)
{
    times.push_back(findTimeSequences.cap(1).toInt());
    posOffset += findTimeSequences.matchedLength();
}

times[2] += 1;

QString outputTime;
for (int i = (int) times.size() - 1; i >= 0; i--)
{
    if (times[i] == 60 && i > 0)
    {
        times[i-1] += 1;
        times[i] = 0;
    }

    QString currentNum; currentNum.setNum(times[i]);
    if (times[i] <= 9 && i >= 0)
    {
        currentNum.insert(0, QString("0"));
    }
    if (i < 2)
    {
        currentNum.append(":");
    }

    outputTime.insert(0, currentNum);
}

ui->Output->setText(outputTime);

}

#endif // CLOCK_APPLICATION_H
@

clock_application.cpp:

@

#include "clock_application.h"
#include "ui_clock_application.h"
#include "QString"
#include "QRegExp"
#include "vector"
#include "QThread"

Clock_Application::Clock_Application(QWidget *parent) :
QMainWindow(parent),
ui(new Ui::Clock_Application)
{
ui->setupUi(this);
}

Clock_Application::~Clock_Application()
{
delete ui;
}
@

MuldeR · wrote on 24 Apr 2012, 11:42

In your header file you are trying to dereference ui, although you only have a forward-declartion of Ui::Clock_Application there! This can't work, obviously. The definition of the Ui::Clock_Application class in "ui_clock_application.h" is included in your .cpp file only! Simply move Clock_Application::changeTime() and Clock_Application::timer_Start() into the .cpp file. These don't belong into the header file anyway...

Solution:

clock_application.h:
@#ifndef CLOCK_APPLICATION_H
#define CLOCK_APPLICATION_H

#include <QMainWindow>
#include <QTimer>
#include <QLineEdit>

namespace Ui {
class Clock_Application; //Only forward-declartion here !!!
}

class Clock_Application : public QMainWindow
{
Q_OBJECT

public:
explicit Clock_Application(QWidget *parent = 0);
~Clock_Application();
public slots:
void timer_Start();
void changeTime();
private:
Ui::Clock_Application ui; //forward-declartion sufficient here
QTimer timer;
};

#endif // CLOCK_APPLICATION_H@

clock_application.cpp:
@#include "clock_application.h"
#include "ui_clock_application.h" //Contains the full class definition
#include "QString"
#include "QRegExp"
#include "vector"
#include "QThread"

Clock_Application::Clock_Application(QWidget *parent) :
QMainWindow(parent),
ui(new Ui::Clock_Application)
{
ui->setupUi(this);
}

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

void Clock_Application::timer_Start()
{
timer = new QTimer();
connect(timer, SIGNAL(timeout()), this, SLOT(changeTime()));
timer->start(1000);
}

void Clock_Application::changeTime()
{
std::vector<int> times;
QRegExp findTimeSequences("(\d+)");
QString currentTime(ui->Output->text()); //Requires full class definition !!!

int posOffset(0);
while ((posOffset = findTimeSequences.indexIn(currentTime, posOffset)) != -1)
{
    times.push_back(findTimeSequences.cap(1).toInt());
    posOffset += findTimeSequences.matchedLength();
}

times[2] += 1;

QString outputTime;
for (int i = (int) times.size() - 1; i >= 0; i--)
{
    if (times[i] == 60 && i > 0)
    {
        times[i-1] += 1;
        times[i] = 0;
    }

    QString currentNum; currentNum.setNum(times[i]);
    if (times[i] <= 9 && i >= 0)
    {
        currentNum.insert(0, QString("0"));
    }
    if (i < 2)
    {
        currentNum.append(":");
    }

    outputTime.insert(0, currentNum);
}

ui->Output->setText(outputTime); //Requires full class definition !!!

}@

Flurite · wrote on 24 Apr 2012, 20:43

Works like a charm. Thanks for all the help!