Qt-первая программа

#ifndef DIALOG_H
#define DIALOG_H
#include <qdialog.h>
#include <QtGui>
 
class QCheckBox;
class QLabel;
class QLineEdit;
class QPushButton;
 
class FindDialog : public QDialog
{
    Q_OBJECT
 public: 
    FindDialog(QWidget* parent=0);
 signals: 
    void findNext(const QString &str, Qt::CaseSensitivity cs);
    void findPrev(const QString &str, Qt::CaseSensitivity cs);
 private slots:
    void findClicked();
    void enableFindButton(const QString &text);//!!!
 private:
    QLabel* label;
    QLineEdit* lineEdit;
    QCheckBox* caseCheckBox;
    QCheckBox* backwardCheckBox;
    QPushButton* findButton;
    QPushButton* closeButton;
};
 
FindDialog::FindDialog(QWidget* parent) : QDialog(parent)
{
    label = new QLabel(tr("fond &what:"));
    lineEdit = new QLineEdit;
    label->setBuddy(lineEdit);
    caseCheckBox = new QCheckBox(tr("Match &case"));
    backwardCheckBox = new QCheckBox(tr("search backward"));
    findButton = new QPushButton(tr("&find"));
    
    findButton->setDefault(true);
    findButton->setEnabled(false);
 
    closeButton = new QPushButton(tr("&quit"));
 
    connect (lineEdit,SIGNAL(textChanged(const QString &)),this,SLOT(enableFindButton(const QString &)));//!!
    connect (findButton,SIGNAL(clicked()),this,SLOT(findClicked()));
    connect (closeButton,SIGNAL(clicked()),this,SLOT(close()));
 
    QHBoxLayout* topLeftLayout = new QHBoxLayout;
    topLeftLayout->addWidget(label);
    topLeftLayout->addWidget(lineEdit);
    
    QVBoxLayout* leftLayout = new QVBoxLayout;
    leftLayout->addLayout(topLeftLayout);
    leftLayout->addWidget(caseCheckBox);
    leftLayout->addWidget(backwardCheckBox);
    
    QVBoxLayout* rightLayout = new QVBoxLayout;
    rightLayout->addWidget(findButton);
    rightLayout->addWidget(closeButton);
    rightLayout->addStretch();
    
    QHBoxLayout* mainLayout = new QHBoxLayout;
    mainLayout->addLayout(leftLayout);
    mainLayout->addLayout(rightLayout);
    setLayout(mainLayout);
    
    setWindowTitle("OLOLo FIND!!!");
    setFixedHeight(sizeHint().height()); 
        
}
 
 
void FindDialog::findClicked()
{
QString text = lineEdit->text();
Qt::CaseSensitivity cs = caseCheckBox->isChecked() ? Qt::CaseSensitive
                         : Qt::CaseInsensitive; 
if (backwardCheckBox->isChecked()){
    emit findPrev(text,cs);}  
else {  emit findNext(text,cs);}
}
 
void FindDialog::enableFindButton(const QString &text)
{
    findButton->setEnabled(!text.isEmpty());
}
 
#endif

#include <QtGui>
#include "dialog.h"
 
 
int main (int argc, char** argv)
{
    QApplication app(argc,argv);
    FindDialog* dialog = new FindDialog;
    dialog->show();
    return app.exec();
}

#ifndef FINDDIALOG_H
#define FINDDIALOG_H
 
#include <QDialog>
 
// Предварительные объявления классов Qt
class QCheckBox;
class QLabel;
class QLineEdit;
class QPushButton;
 
class finddialog : public QDialog
{
    Q_OBJECT
public:
    explicit finddialog(QWidget *parent = 0);
 
signals:
    void findNext(const QString &str, Qt::CaseSensitivity cs);
    void findPrev(const QString &str, Qt::CaseSensitivity cs);
 
private slots:
    void findClicked();
    void enableFindButton(const QString &text);
 
private:
    QLabel *label;
    QLineEdit *lineEdit;
    QCheckBox *caseCheckBox;
    QCheckBox *backwardCheckBox;
    QPushButton *findButton;
    QPushButton *closeButton;
};
 
#endif // FINDDIALOG_H

#include "finddialog.h"
#include <QtGui>
 
finddialog::finddialog(QWidget *parent) :
    QDialog(parent)
{
    label = new QLabel(tr("Find &what:"));
    lineEdit = new QLineEdit;
    label->setBuddy(lineEdit);
 
    caseCheckBox = new QCheckBox(tr("Match &case"));
    backwardCheckBox = new QCheckBox(tr("Search backward"));
 
    findButton = new QPushButton(tr("&Find"));
    findButton->setDefault(true);
    findButton->setEnabled(false);
 
    closeButton = new QPushButton(tr("Close"));
 
    connect(lineEdit, SIGNAL(textChanged(const QString &)), this, SLOT(enableFindButton(const QString &)));
    connect(findButton, SIGNAL(clicked()), this, SLOT(findClicked()));
    connect(closeButton, SIGNAL(clicked()), this, SLOT(close()));
 
    QHBoxLayout *topLeftLayout = new QHBoxLayout;
    topLeftLayout->addWidget(label);
    topLeftLayout->addWidget(lineEdit);
 
    QVBoxLayout *leftLayout = new QVBoxLayout;
    leftLayout->addLayout(topLeftLayout);
    leftLayout->addWidget(caseCheckBox);
    leftLayout->addWidget(backwardCheckBox);
 
    QVBoxLayout *rightLayout = new QVBoxLayout;
    rightLayout->addWidget(findButton);
    rightLayout->addWidget(closeButton);
    rightLayout->addStretch();
 
    QHBoxLayout *mainLayout = new QHBoxLayout;
    mainLayout->addLayout(leftLayout);
    mainLayout->addLayout(rightLayout);
    setLayout(mainLayout);
 
    setWindowTitle(tr("Find"));
    setFixedHeight(sizeHint().height());
}
 
void finddialog::findClicked() {
    QString text = lineEdit->text();
    Qt::CaseSensitivity cs = caseCheckBox->isChecked() ? Qt::CaseSensitive : Qt::CaseInsensitive;
 
    if (backwardCheckBox->isChecked()) {
        emit findPrev(text, cs);
    } else {
        emit findNext(text, cs);
    }
}
 
void finddialog::enableFindButton(const QString &text) {
    findButton->setEnabled(!text.isEmpty());
}

#include <QApplication>
 
#include "finddialog.h"
 
int main(int argc, char *argv[])
{
    QApplication app(argc, argv);
    FindDialog *dialog = new FindDialog;
    dialog->show();
    return app.exec();
}

void MainWindow::on_search_clicked()
{
    finddialog *dialog = new finddialog(this);
    dialog->exec();
}