2.1 子类化QDialog

//UIFindDialog.h
#ifndef UIFINDDIALOG
#define UIFINDDIALOG
#include <QDialog>
//类的前置声明
//对于该类中的所有私有变量来说前置声明是可行的
//前置声明告知编译器类的存在，而不需要提供类的实现细节
//可以加快编译速度
class QLabel;
class QCheckBox;
class QLineEdit;
class QPushButton;
class UIFindDialog : public QDialog
{
    //对于所有定义了信号和槽的类
    //都必须在类定义的开始处声明宏 Q_OBJECT
    Q_OBJECT
public:
    explicit UIFindDialog(QWidget *pParent = 0);
    //自定义信号函数
    //信号函数只需要声明，不需要实现
signals:
    void sigFindNext(const QString& str, Qt::CaseSensitivity cs);
    void sigFindPrevious(const QString& str, Qt::CaseSensitivity cs);
    //自定义槽函数
private slots:
    void slotFindClicked();
    void slotEnableFindButton(const QString& strText);
private:
    QLabel      *m_pTextLabel;
    QLineEdit   *m_pKeywordEdit;
    QCheckBox   *m_pCaseCheckBox;
    QCheckBox   *m_pBackwardCheckBox;
    QPushButton *m_pFindButton;
    QPushButton *m_pCloseButton;
};
#endif
//UIFindDialog.cpp
#include <QtGui>
#include "UIFindDialog.h"
UIFindDialog::UIFindDialog(QWidget* pParent)
    : QDialog(pParent)
{
    m_pTextLabel = new QLabel(tr("查找"));
    m_pKeywordEdit = new QLineEdit;
    m_pTextLabel->setBuddy(m_pKeywordEdit);
    m_pCaseCheckBox = new QCheckBox(tr("区分大小写"));
    m_pBackwardCheckBox = new QCheckBox(tr("从前向后"));
    m_pFindButton = new QPushButton(tr("查找"));
    m_pFindButton->setDefault(true);
    m_pFindButton->setEnabled(false);
    m_pCloseButton = new QPushButton(tr("关闭"));

    QHBoxLayout* pTopLeftLayout = new QHBoxLayout;
    pTopLeftLayout->addWidget(m_pTextLabel);
    pTopLeftLayout->addWidget(m_pKeywordEdit);

    QVBoxLayout* pLeftLayout = new QVBoxLayout;
    pLeftLayout->addLayout(pTopLeftLayout);
    pLeftLayout->addWidget(m_pCaseCheckBox);
    pLeftLayout->addWidget(m_pBackwardCheckBox);

    QVBoxLayout* pRightLayout = new QVBoxLayout;
    pRightLayout->addWidget(m_pFindButton);
    pRightLayout->addWidget(m_pCloseButton);

    QHBoxLayout* pMainLayout = new QHBoxLayout;
    pMainLayout->addLayout(pLeftLayout);
    pMainLayout->addLayout(pRightLayout);
    this->setLayout(pMainLayout);

    //调用QObject::connect(); 函数进行槽连接时，注意参数是否匹配
    //1.信号函数的参数列表与槽函数的参数列表完全相同
    //2.信号函数的参数个数大于槽函数参数个数，
    //  且两个参数列表中的参数类型从左向右相匹配
    //  多余的参数将被忽略掉
    //3.注意参数列表中const属性
    connect(m_pKeywordEdit, SIGNAL(textChanged(const QString&)),
            this, SLOT(slotEnableFindButton(const QString&)));
    connect(m_pCloseButton, SIGNAL(clicked()),
            this, SLOT(close()));
}
void UIFindDialog::slotFindClicked()
{
    QString strKeyword = m_pKeywordEdit->text();

    //判断是否区分大小写
    Qt::CaseSensitivity cs =                //区分                    //不区分
            m_pCaseCheckBox->isChecked() ? Qt::CaseSensitive : Qt::CaseInsensitive;
    if (m_pBackwardCheckBox->isChecked())
    {   //向前查找
        emit sigFindPrevious(strKeyword, cs);
    }
    else
    {   //向后查找
        emit sigFindNext(strKeyword, cs);
    }
}
void UIFindDialog::slotEnableFindButton(const QString& strText)
{
    m_pFindButton->setEnabled(!strText.isEmpty());
}
//main.cpp
#include <QApplication>
#include <QTextCodec>
#include "UIFindDialog.h"
int main(int argc, char** argv)
{
    QApplication app(argc, argv);
    //对汉字进行编解码
    QTextCodec::setCodecForTr(QTextCodec::codecForLocale());

    UIFindDialog dialog;
    dialog.show();
    return app.exec();
}

图片:4.png