使用C++编写的一个Find（查找）对话框例子

//findDialog.h 头文件

 1 //finddialog.h
 2 #ifndef FINDDIALOG_H
 3 #define FINDDIALOG_H
 4 
 5 #include <QDialog>
 6 
 7 class QCheckBox;
 8 class QLabel;
 9 class QLineEdit;
10 class QPushButton;
11 
12 
13 class FindDialog : public QDialog
14 {
15     Q_OBJECT
16 
17 public:
18     FindDialog(QWidget *parent = 0);
19 signals:
20     void findNext(const QString &str,Qt::CaseSensitivity cs);
21     void findPrevious(const QString &str,Qt::CaseSensitivity cs);
22 private slots:
23     void findClicked();
24     void enableFindButton(const QString &text);
25 private:
26     QLabel *label;
27     QLineEdit *lineEdit;
28     QCheckBox *caseCheckBox;
29     QCheckBox *backwardCheckBox;
30     QPushButton *findButton;
31     QPushButton *closeButton;
32 };
33 
34 #endif // FINDDIALOG_H

//findDialog.cpp 实现文件

 1 //finddialog.cpp
 2 #include <QtGui>
 3 #include "finddialog.h"
 4 
 5 FindDialog::FindDialog(QWidget *parent):QDialog(parent)
 6 {
 7     label = new QLabel(tr("Find &what")); //tr()函数是把他们翻译成其他语言的标记
 8     lineEdit = new QLineEdit;
 9     label->setBuddy(lineEdit);  //设置了行编辑器作为标签的伙伴（buddy）
10                                 //所谓“buddy”是指一个窗口部件，它可以在按下标签的快捷键时接受焦点（focus）
11     caseCheckBox = new QCheckBox(tr("Match &case"));
12     backwardCheckBox = new QCheckBox(tr("Search &backward"));
13 
14     findButton = new QPushButton(tr("&Find"));
15     findButton->setDefault(true);  //setDefault（）让Find按钮成为对话框的默认按钮（default button）。
16                                    //default button 就是指当用户按下Enter健时能够按下对应的按钮
17     findButton->setEnabled(false); //默认禁止，显示灰色
18     closeButton = new QPushButton(tr("Close"));
19     connect(lineEdit,SIGNAL(textChanged(const QString &)),this,SLOT(enableFindButton(const QString &)));
20     connect(findButton,SIGNAL(clicked()),this,SLOT(findClicked()));
21     connect(closeButton,SIGNAL(clicked()),this,SLOT(close()));
22 
23     QHBoxLayout *topLeftLayout = new QHBoxLayout;
24     topLeftLayout->addWidget(label);
25     topLeftLayout->addWidget(lineEdit);
26     QVBoxLayout *leftLayout = new QVBoxLayout;
27     leftLayout->addLayout(topLeftLayout);
28     leftLayout->addWidget(caseCheckBox);
29     leftLayout->addWidget(backwardCheckBox);
30     QVBoxLayout *rightLayout = new QVBoxLayout;
31     rightLayout->addWidget(findButton);
32     rightLayout->addWidget(closeButton);
33     rightLayout->addStretch();  //添加分隔符（Stretch）
34 
35     QHBoxLayout *mainLayout = new QHBoxLayout;
36     mainLayout->addLayout(leftLayout);
37     mainLayout->addLayout(rightLayout);
38     this->setLayout(mainLayout);
39 
40     setWindowTitle(tr("Find"));
41     setFixedHeight(sizeHint().height()); //让窗口具有一个固定的高度，对话框
42 
43 };
44 
45 void FindDialog::findClicked()
46 {
47     QString text = lineEdit->text();  //取编辑框中的文本保存在一个String中
48     Qt::CaseSensitivity cs = caseCheckBox->isChecked()?Qt::CaseSensitive:Qt::CaseInsensitive;//Qt::CaseSensitivity 是一个枚举类型
49     if(backwardCheckBox->isChecked())
50         emit findPrevious(text,cs);
51     else
52         emit findNext(text,cs);
53 }
54 
55 void FindDialog::enableFindButton(const QString &text)
56 {
57     findButton->setEnabled(!text.isEmpty());
58 }

//main.cpp 测试函数

 1 //main.cpp
 2 #include <QApplication>
 3 #include "finddialog.h"
 4 
 5 int main(int argc,char *argv[])
 6 {
 7     QApplication app(argc,argv);
 8     FindDialog *dialog = new FindDialog;
 9     dialog->show();
10 
11     return app.exec();
12 }

//执行结果