QLineEdit && QLabel

[jacek]

To make it work you have to add Q_OBJECT macro like this:

class mojClass : public QWidget
{
   Q_OBJECT
   public:
      ...

class mojClass : public QWidget
{
   Q_OBJECT
   public:
      ...

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Each class that defines new slots or signals must contain Q_OBJECT macro. Also remember to rerun qmake if you add that macro somewhere.

If you have placed everything in a single file, say somefile.cpp, you have to add #include "somefile.moc" at the end and rerun qmake. This isn't necessary if you have placed class definition in a header file.

[eleanor]

Aha thank you.

If I want to use 3 files, is this correct:

poskus.h

#idndef POSKUS_H
#define POSKUS_H
 
#include <qwidget.h>
 
class mojClass : public QWidget
{
    Q_OBJECT
 public:
    mojClass();
 private:
    QLineEdit *lineedit1;
    QLabel *label1;
    QLabel *label2;
    QLabel *label3;
    QValidator *validator;
 private slots:
    void customSlot(const QString &input);
 
};
 
#endif

#idndef POSKUS_H
#define POSKUS_H

#include <qwidget.h>

class mojClass : public QWidget
{
    Q_OBJECT
 public:
    mojClass();
 private:
    QLineEdit *lineedit1;
    QLabel *label1;
    QLabel *label2;
    QLabel *label3;
    QValidator *validator;
 private slots:
    void customSlot(const QString &input);

};

#endif

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poskus.cpp

#include "poskus.h"
#include <qlineedit.h>
#include <qlabel.h>
#include <qlayout.h>
#include <qvalidator.h>
 
void mojClass::customSlot(const QString &input)
{
    int num = 4 * input.toInt();
    label3->setNum(num);
}
 
 
mojClass::mojClass()
{
    setGeometry(100,100,300,200);
 
    validator = new QIntValidator(100,99999,this);
    lineedit1 = new QLineEdit(this);
    lineedit1->setGeometry(110,10,50,20);
    lineedit1->setEchoMode(QLineEdit::Normal);
    lineedit1->setMaxLength(6);
    lineedit1->setValidator(validator);
 
    label1 = new QLabel(this);
    label1->setGeometry(10,10,100,20);
    label1->setText("Enter something: ");
 
    label2 = new QLabel(this);
    label2->setGeometry(10,40,100,20);
    label2->setText("You've entered: ");
 
    label3 = new QLabel(this);
    label3->setGeometry(120,40,100,20);
 
    connect(lineedit1,SIGNAL(textChanged(const QString &)),this,SLOT(customSlot(const QString &)));
}

#include "poskus.h"
#include <qlineedit.h>
#include <qlabel.h>
#include <qlayout.h>
#include <qvalidator.h>

void mojClass::customSlot(const QString &input)
{
    int num = 4 * input.toInt();
    label3->setNum(num);
}


mojClass::mojClass()
{
    setGeometry(100,100,300,200);

    validator = new QIntValidator(100,99999,this);
    lineedit1 = new QLineEdit(this);
    lineedit1->setGeometry(110,10,50,20);
    lineedit1->setEchoMode(QLineEdit::Normal);
    lineedit1->setMaxLength(6);
    lineedit1->setValidator(validator);

    label1 = new QLabel(this);
    label1->setGeometry(10,10,100,20);
    label1->setText("Enter something: ");

    label2 = new QLabel(this);
    label2->setGeometry(10,40,100,20);
    label2->setText("You've entered: ");

    label3 = new QLabel(this);
    label3->setGeometry(120,40,100,20);

    connect(lineedit1,SIGNAL(textChanged(const QString &)),this,SLOT(customSlot(const QString &)));
}

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main.cpp

#include <qapplication.h>
 
#include "poskus.h"
 
int main(int argc, char **argv)
{
    QApplication a(argc,argv);
    mojClass objekt;
    a.setMainWidget(&objekt);
    objekt.show();
    a.exec();
}

#include <qapplication.h>

#include "poskus.h"

int main(int argc, char **argv)
{
    QApplication a(argc,argv);
    mojClass objekt;
    a.setMainWidget(&objekt);
    objekt.show();
    a.exec();
}

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[jacek]

If I want to use 3 files, is this correct:

It looks OK.