#ifndef LABEL_H
#define LABEL_H
 
#include <QWidget>
#include <QApplication>
#include <QLabel>
 
class Label : public QWidget
{
  public:
    Label(QWidget *parent = 0);
 
  private:
    QLabel *label;
 
};
 
#endif
 

 
#include "label.h"
#include <QVBoxLayout>
#include <QFont>
 
 
Label::Label(QWidget *parent)
    : QWidget(parent)
{
 
  QString lyrics = "Who doesn't long for someone to holdn
Who knows how to love you without being toldn
Somebody tell me why I'm on my ownn
If there's a soulmate for everyonen
n
Here we are again, circles never endn
How do I find the perfect fitn
There's enough for everyonen
But I'm still waiting in linen
n
Who doesn't long for someone to holdn
Who knows how to love you without being toldn
Somebody tell me why I'm on my ownn
If there's a soulmate for everyone";
 
  label = new QLabel(lyrics, this);
  label->setFont(QFont("Purisa", 10));
 
  QVBoxLayout *vbox = new QVBoxLayout();
  vbox->addWidget(label);
  setLayout(vbox);
 
}
 

 
#include "label.h"
#include <QTextStream>
#include <QDesktopWidget>
 
void center(QWidget &widget)
{
  int x, y;
  int screenWidth;
  int screenHeight;
  int width, height;
  QSize windowSize;
 
  QDesktopWidget *desktop = QApplication::desktop();
 
  width = widget.frameGeometry().width();
  height = widget.frameGeometry().height();
 
  screenWidth = desktop->width();
  screenHeight = desktop->height();
 
  x = (screenWidth - width) / 2;
  y = (screenHeight - height) / 2;
 
  widget.move( x, y );
 
}
 
 
int main(int argc, char *argv[])
{
  QApplication app(argc, argv);  
 
  Label window;
 
  window.setWindowTitle("QSlider");
  window.show();
  center(window);
 
  return app.exec();
}
 

 
#ifndef SLIDER_H
#define SLIDER_H
 
#include <QWidget>
#include <QApplication>
#include <QSlider>
#include <QLabel>
 
class Slider : public QWidget
{
  Q_OBJECT
 
  public:
    Slider(QWidget *parent = 0);
 
  private:
    QSlider *slider; 
    QLabel *label;
 
};
 
#endif
 

 
#include "slider.h"
#include <QDesktopWidget>
 
void center(QWidget *widget, int w, int h)
{
  int x, y;
  int screenWidth;
  int screenHeight;
 
  QDesktopWidget *desktop = QApplication::desktop();
 
  screenWidth = desktop->width();
  screenHeight = desktop->height();
 
  x = (screenWidth - w) / 2;
  y = (screenHeight - h) / 2;
 
  widget->move( x, y );
}
 
 
Slider::Slider(QWidget *parent)
    : QWidget(parent)
{
  int WIDTH = 300;
  int HEIGHT = 140;
 
  resize(WIDTH, HEIGHT);
 
  slider = new QSlider(Qt::Horizontal , this);
  slider->setGeometry(50, 50, 130, 30);
 
 
  label = new QLabel("0", this);
  label->setGeometry(230, 50, 20, 30);
 
  connect(slider, SIGNAL(valueChanged(int)), label, SLOT(setNum(int)));
 
  center(this, WIDTH, HEIGHT);
 
}
 

 
#include "slider.h"
 
int main(int argc, char *argv[])
{
  QApplication app(argc, argv);  
 
  Slider window;
 
  window.setWindowTitle("QSlider");
  window.show();
 
  return app.exec();
}
 

 
#ifndef SPINBOX_H
#define SPINBOX_H
 
#include <QWidget>
#include <QApplication>
#include <QSpinBox>
 
class SpinBox : public QWidget
{
  Q_OBJECT
 
  public:
    SpinBox(QWidget *parent = 0);
 
  private slots:
    void setTitle(int);
 
  private:
    QSpinBox *spinbox;
 
};
 
#endif
 

 
#include "spinbox.h"
 
SpinBox::SpinBox(QWidget *parent)
    : QWidget(parent)
{
  spinbox = new QSpinBox(this);
  spinbox->setGeometry(50, 50, 60, 30);
 
  connect(spinbox, SIGNAL(valueChanged(int)), 
      this, SLOT(setTitle(int)));
 
}
 
void SpinBox::setTitle(int val) 
{
  setWindowTitle(QString::number(val));
}
 

 
#include "spinbox.h"
#include <QDesktopWidget>
 
void center(QWidget &widget)
{
  int x, y;
  int screenWidth;
  int screenHeight;
 
  int WIDTH = 250;
  int HEIGHT = 170;
 
 
  QDesktopWidget *desktop = QApplication::desktop();
 
  screenWidth = desktop->width();
  screenHeight = desktop->height();
 
  x = (screenWidth - WIDTH) / 2;
  y = (screenHeight - HEIGHT) / 2;
 
  widget.setGeometry(x, y, WIDTH, HEIGHT);
 
}
 
 
int main(int argc, char *argv[])
{
  QApplication app(argc, argv);
 
  SpinBox window;
 
  window.setWindowTitle("0");
  window.show();
  center(window);
 
  return app.exec();
}
 

 
#ifndef LEDIT_H
#define LEDIT_H
 
#include <QWidget>
 
class Ledit : public QWidget
{
  public:
    Ledit(QWidget *parent = 0);
 
};
 
#endif
 

 
#include "ledit.h"
#include <QGridLayout>
#include <QLabel>
#include <QLineEdit>
 
Ledit::Ledit(QWidget *parent)
    : QWidget(parent)
{
 
  QLabel *name = new QLabel("Name:", this);
  QLabel *age = new QLabel("Age:", this);
  QLabel *occupation = new QLabel("Occupation:", this);
 
  QLineEdit *le1 = new QLineEdit(this);
  QLineEdit *le2 = new QLineEdit(this);
  QLineEdit *le3 = new QLineEdit(this);
 
  QGridLayout *grid = new QGridLayout(); 
 
  grid->addWidget(name, 0, 0);
  grid->addWidget(le1, 0, 1);
  grid->addWidget(age, 1, 0);
  grid->addWidget(le2, 1, 1);
  grid->addWidget(occupation, 2, 0);
  grid->addWidget(le3, 2, 1);
 
  setLayout(grid);
}
 

 
#include "ledit.h"
#include <QDesktopWidget>
#include <QApplication>
 
void center(QWidget &widget)
{
  int x, y;
  int screenWidth;
  int screenHeight;
 
  int WIDTH = 250;
  int HEIGHT = 170;
 
 
  QDesktopWidget *desktop = QApplication::desktop();
 
  screenWidth = desktop->width();
  screenHeight = desktop->height();
 
  x = (screenWidth - WIDTH) / 2;
  y = (screenHeight - HEIGHT) / 2;
 
  widget.setGeometry(x, y, WIDTH, HEIGHT);
 
}
 
 
int main(int argc, char *argv[])
{
  QApplication app(argc, argv);  
 
  Ledit window;
 
  window.setWindowTitle("QLineEdit");
  window.show();
  center(window);
 
  return app.exec();
}
 

 
#ifndef STATUSBAR_H
#define STATUSBAR_H
 
#include <QMainWindow>
#include <QPushButton>
 
class Statusbar : public QMainWindow
{
  Q_OBJECT  
 
  public:
    Statusbar(QWidget *parent = 0);
 
  private slots:
    void OnOkPressed();
    void OnApplyPressed();
 
  private:
    QPushButton *ok;
    QPushButton *apply;
 
};
 
#endif
 

 
statusbar.cpp
#include "statusbar.h"
#include <QGridLayout>
#include <QLabel>
#include <QFrame>
#include <QStatusBar>
 
Statusbar::Statusbar(QWidget *parent)
    : QMainWindow(parent)
{
 
  QFrame *frame = new QFrame(this);
  setCentralWidget(frame);
 
  ok = new QPushButton("OK", frame);
  ok->move(20, 50);
 
  apply = new QPushButton("Apply", frame);
  apply->move(120, 50);
 
  statusBar();
 
  connect(ok, SIGNAL(clicked()), this, SLOT(OnOkPressed()));
  connect(apply, SIGNAL(clicked()), this, SLOT(OnApplyPressed()));
}
 
void Statusbar::OnOkPressed()
{
  statusBar()->showMessage("OK button pressed", 2000);
}
 
void Statusbar::OnApplyPressed()
{
 statusBar()->showMessage("Apply button pressed", 2000);
}
 

 
#include "statusbar.h"
#include <QDesktopWidget>
#include <QApplication>
 
void center(QWidget &widget)
{
  int x, y;
  int screenWidth;
  int screenHeight;
 
  int WIDTH = 250;
  int HEIGHT = 170;
 
 
  QDesktopWidget *desktop = QApplication::desktop();
 
  screenWidth = desktop->width();
  screenHeight = desktop->height();
 
  x = (screenWidth - WIDTH) / 2;
  y = (screenHeight - HEIGHT) / 2;
 
  widget.setGeometry(x, y, WIDTH, HEIGHT);
 
}
 
 
int main(int argc, char *argv[])
{
  QApplication app(argc, argv);  
 
  Statusbar window;
 
  window.setWindowTitle("QStatusBar");
  window.show();
  center(window);
 
  return app.exec();
}