QT练习4:编写一个查找对话框

分为3个文件:

finddialog.h:

#ifndef FINDDIALOG_H
#define FINDDIALOG_H

#include <QDialog>

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

//自定义类,继承于QDialog
class FindDialog:public QDialog
{
    Q_OBJECT
public:
    FindDialog(QWidget *parent=0);//构造函数

signals:
    void findNext(const QString &str,bool caseSensitive);
    void findPrev(const QString &str,bool caseSensitive);
private slots://私有槽
    void findClicked();
    void enableFindButton(const QString &text);

private:
    //声明窗口要使用到的部件
    QLabel *label;
    QLineEdit *lineEdit;
    QCheckBox *caseCheckBox;
    QCheckBox *backwardCheckBox;
    QPushButton *findButton;
    QPushButton *closeButton;

};

#endif // FINDDIALOG_H

finddialog.cpp

#include <QCheckBox>
#include <QLabel>
#include <QLayout>
#include <QLineEdit>
#include <QPushButton>

#include "finddialog.h"

FindDialog::FindDialog(QWidget *parent)
    :QDialog(parent)//对父类进行构造
{
    label = new QLabel(tr("Find &what:"),this);
    lineEdit = new QLineEdit("wenhao",this);
    label->setBuddy(lineEdit);//label,lineEdit是伙伴关系.按label的快捷键进入lineEdit中


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

    findButton = new QPushButton(tr("&Find"),this);
    findButton->setDefault(true);//接回车键相当于按下findButton键
    findButton->setEnabled(false);//这个设置让其默认是不可以点击的.

    closeButton = new QPushButton(tr("Close"),this);
    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(1);//

    QHBoxLayout *mainLayout = new QHBoxLayout(this);
    mainLayout->setMargin(11);
    mainLayout->setSpacing(4);
    mainLayout->addLayout(leftLayout);
    mainLayout->addLayout(rightLayout);
    setLayout(mainLayout);

    setWindowTitle(tr("Find..."));
}


void FindDialog::findClicked()
{
    QString text = lineEdit->text();
    bool caseSensitive = caseCheckBox->isChecked();

    if(backwardCheckBox->isChecked())
        emit findPrev(text,caseSensitive);
    else
        emit findNext(text,caseSensitive);
}

void FindDialog::enableFindButton(const QString &text)
{
    findButton->setEnabled(!text.isEmpty());
}

main.cpp

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

效果图: