QDialog

一．子类化QDialog

说一下学习感受，学习这个Qt子类化对话框其实有代码了，觉得挺方便的，执行一个qmake +项目文件生成与平台相关的Makefile文件，然后执行make编译源代码，生成与目标程序与执行文件。然后再执行可执行文件，对话框就跑出来了。很快很爽的做出来了。兴奋过后觉得自己也没学到什么呀！接着要深入了解程序，了解它的程序含义及程序运行原理。这是个designer的设计效果图。

从上面可以了解到，创建一个Find对话框，需要什么窗口部件。一个没有按钮的对话框（Dialog without Button）,一个标签（label），一个行编辑器（lineEdit），两个复选框按钮(CheckBox)，两个按键按钮(PushButton)，一个垂直分隔符。

我的思路是这样的想把框架创建好，在建立信号和槽。

创建一个finddialog.h头文件

#ifndef FINDDIALOG_H

#define FINDDIALOG_H

#include

Class FINDDIALOG:public QDialog

{

       Public:

       FindDialog(QWidget *parent = 0);     

};

#endif

FindDialog的的头文件的建好了

创建一个finddialog.cpp C++源文件

 

#include

#include “finddialog.h”

FindDialog::FindDialog(QWidget *parent)

       :QDialog(parent)

{

 

}

 

内容先不写进去先。

创建一个main.cpp文件

#include

#include “finddialog.h”

int main(int argc,char *argv[])

{

       QApplication app(argc,argv);

       FindDialog *dialog = new FindDialog;

       Dialog->show();

       return app.exec();

}

运行效果是这样的：

接下来添加标签，行编辑器，在finddialog.h中定义两个类，分别是QLabel和QLineEdit，定义两个私有对象分别为label和lineEdit.然后再finddialog.cpp源文件中声明，建立label和lineEdit两个对象的关系。定义一个水平布局管理器。管理label和lineEdit两个窗口部件的大小和位置。

接着添加两个CheckBox,原理是一样的，在finddialog.h中定义一个复选框类，两个复选框对象。在finddialog.cpp中引用定义的复选框对象。运行看效果有点模样了

以同样的方式创建Button按钮，及布局管理器。运行看效果，成了。不过还有信号和槽连接

最后创建信号与槽私有的，当行编辑器中输入字符串是，就会调用私有的槽enableFindButton（const QString &）.Find按钮变成启用状态，当按下Find按钮就会调用findClicked()的私有槽。当用户单击Close时，对话框会关闭。Close（）槽是从窗口部件QWidget类函数中继承而来的，并且它默认行为就是把窗口部件从用户的视野中隐藏起来（而无须将其删除）。在建立信号和槽连接时QObject::connect（）应该是这样写的，但由于QObject是FindDialog的父对象之一，因此可以省略connect（）函数前面的QObject：：前缀。最后运行代码。。代码：

finddialog.h头文件

#ifndef FINDDIALOG_H

#define FINDDIALOG_H                                                                             

#include                                                                              

class QLabel;

class QLineEdit;

class QCheckBox;

class QPushCheckBox;

                                                                               

class FindDialog:public QDialog

{

        Q_OBJECT

                                                                                

        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

 finddialog.h源文件，要实现的功能都在这个文件里对象引用，窗口部件布局，信号和槽的链接等等。。

 

#include

#include "finddialog.h"

                                                                              

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 findPrevious(text,cs);

} else {

        emit findNext(text,cs);

 }

                                                                               

}

                                                                              

void FindDialog::enableFindButton(const QString &text)

{

        findButton->setEnabled(!text.isEmpty());

}

 

主函数main.cpp源文件

#include

#include "finddialog.h"                                                                   

int main(int argc,char *argv[])

{

        QApplication app(argc,argv);

        FindDialog *dialog = new FindDialog;

        dialog->show();

        return app.exec();

}

 

 

 

奋斗还在进行中....

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