Qt 创建对话框

#ifndef FINDDIALOG_H
#define FINDDIALOG_H

#include <QDialog>

class QCheckBox;
class QLabel;
class QLineEdit;
class QPushButton;

class FindDialog : public QDialog
{
Q_OBJECT //对于所有定义了信号和槽的类，在定义开始处的Q_OBJECT都是必需的

public:
FindDialog(QWidget *parent = 0);

signals:
void findNext(const QString &str, Qt::CaseSensitivity cs);
void findPrevious(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

#include <QLabel>
#include <QCheckBox>
#include <QPushButton>
#include <QHBoxLayout>
#include <QVBoxLayout>
#include <QLineEdit>

#include "finddialog.h"

FindDialog::FindDialog(QWidget *parent)
: QDialog(parent)
{
label = new QLabel(tr("Find &what:"));//快捷键Alt+W
lineEdit = new QLineEdit;
label->setBuddy(lineEdit); //设置接收快捷键焦点的伙伴

caseCheckBox = new QCheckBox(tr("Match &case"));
backwardCheckBox = new QCheckBox(tr("Search &backward"));

findButton = new QPushButton(tr("&Find"));
findButton->setDefault(true); //默认按钮
findButton->setEnabled(false);//禁用按钮

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();//添加弹簧（伸展器）

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 findPrevious(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();
}