最近在阅读Qt 5.9 C++开发指南，为了加深对书本上内容的理解，参照书上的讲解尝试写了一些demo，用于以后工作中查阅，如果涉及侵权请告知，实例程序samp2_3

mydialog.h

#ifndef MYDIALOG_H
#define MYDIALOG_H

#include
#include
#include
#include
#include
#include
#include
#include
#include

class MyDialog : public QDialog
{
Q_OBJECT

private:
QCheckBox *underlineCheckBox;
QCheckBox *italicCheckBox;
QCheckBox *boldCheckBox;
QRadioButton *blackRadioButton;
QRadioButton *redRadioButton;
QRadioButton *blueRadioButton;
QPlainTextEdit *plainTextEdit;
QPushButton *okPushButton;
QPushButton *cancelPushButton;
QPushButton *closePushButton;

public:
MyDialog(QWidget *parent = nullptr);
~MyDialog();
void iniUI();
void iniSignalSlots();

public slots:
void onUnderlineCheckBox(bool checked);
void onItalicCheckBox(bool checked);
void onBoldCheckBox(bool checked);
void setTextFontColor();
void onOkPushButton();
void onCancelPushButton();
};

#endif // MYDIALOG_H

mydialog.cpp

#include "mydialog.h"

MyDialog::MyDialog(QWidget *parent) : QDialog(parent)
{
iniUI();
iniSignalSlots();
}

MyDialog::~MyDialog()
{

}

/*
* 初始化界面
*/
void MyDialog::iniUI()
{
// 初始化三个复选框
underlineCheckBox = new QCheckBox(tr("Underline"));
italicCheckBox = new QCheckBox(tr("Italic"));
boldCheckBox = new QCheckBox(tr("Bold"));

// 将三个复选框放在一个水平布局内  
QHBoxLayout \*hlayout1 = new QHBoxLayout();  
hlayout1->addWidget(underlineCheckBox);  
hlayout1->addWidget(italicCheckBox);  
hlayout1->addWidget(boldCheckBox);

// 初始化三个单选按钮  
blackRadioButton = new QRadioButton(tr("Black"));  
blackRadioButton->setChecked(true);  
redRadioButton = new QRadioButton(tr("Red"));  
blueRadioButton = new QRadioButton(tr("Blue"));

// 将三个单选按钮放在一个水平布局内  
QHBoxLayout \*hlayout2 = new QHBoxLayout();  
hlayout2->addWidget(blackRadioButton);  
hlayout2->addWidget(redRadioButton);  
hlayout2->addWidget(blueRadioButton);

// 初始化文本框  
plainTextEdit = new QPlainTextEdit();

// 初始化三个按钮  
okPushButton = new QPushButton(tr("确定"));  
cancelPushButton = new QPushButton(tr("取消"));  
closePushButton = new QPushButton(tr("退出"));

// 将三个按钮放在一个水平布局内  
QHBoxLayout \*hlayout3 = new QHBoxLayout();  
hlayout3->addWidget(okPushButton);  
hlayout3->addWidget(cancelPushButton);  
hlayout3->addWidget(closePushButton);

// 将三个水平布局放在一个垂直布局内，并设置为窗口整体布局  
QVBoxLayout \*vlayout = new QVBoxLayout();  
vlayout->addLayout(hlayout1);  
vlayout->addLayout(hlayout2);  
vlayout->addWidget(plainTextEdit);  
vlayout->addLayout(hlayout3);  
setLayout(vlayout);

resize(,);  

}

/*
* 初始化信号与槽
*/
void MyDialog::iniSignalSlots()
{
// 处理三个复选框
connect(underlineCheckBox, SIGNAL(clicked(bool)), this, SLOT(onUnderlineCheckBox(bool)));
connect(italicCheckBox, SIGNAL(clicked(bool)), this, SLOT(onItalicCheckBox(bool)));
connect(boldCheckBox, SIGNAL(clicked(bool)), this, SLOT(onBoldCheckBox(bool)));

// 处理三个单选按钮  
connect(blackRadioButton, SIGNAL(clicked()), this, SLOT(setTextFontColor()));  
connect(redRadioButton, SIGNAL(clicked()), this, SLOT(setTextFontColor()));  
connect(blueRadioButton, SIGNAL(clicked()), this, SLOT(setTextFontColor()));

// 处理三个普通按钮  
connect(okPushButton, SIGNAL(clicked()), this, SLOT(onOkPushButton()));  
connect(cancelPushButton, SIGNAL(clicked()), this, SLOT(onCancelPushButton()));  
connect(closePushButton, SIGNAL(clicked()), this, SLOT(close()));  

}

/*
* 当用户点击下划线复选框的槽函数
*/
void MyDialog::onUnderlineCheckBox(bool checked)
{
QFont font = plainTextEdit->font();
font.setUnderline(checked);
plainTextEdit->setFont(font);
}

/*
* 当用户点击斜体复选框的槽函数
*/
void MyDialog::onItalicCheckBox(bool checked)
{
QFont font = plainTextEdit->font();
font.setItalic(checked);
plainTextEdit->setFont(font);
}

/*
* 当用户点击加粗复选框的槽函数
*/
void MyDialog::onBoldCheckBox(bool checked)
{
QFont font = plainTextEdit->font();
font.setBold(checked);
plainTextEdit->setFont(font);
}

/*
* 当用户点击单选按钮的槽函数
*/
void MyDialog::setTextFontColor()
{
if(blackRadioButton->isChecked())
{
QPalette pa;
pa.setColor(QPalette::Text, Qt::black);
plainTextEdit->setPalette(pa);
}
else if(redRadioButton->isChecked())
{
QPalette pa;
pa.setColor(QPalette::Text, Qt::red);
plainTextEdit->setPalette(pa);
}
else
{
QPalette pa;
pa.setColor(QPalette::Text, Qt::blue);
plainTextEdit->setPalette(pa);
}
}

/*
* 当用户点击确定按钮的槽函数
*/
void MyDialog::onOkPushButton()
{
underlineCheckBox->setEnabled(false);
italicCheckBox->setEnabled(false);
boldCheckBox->setEnabled(false);
blackRadioButton->setEnabled(false);
redRadioButton->setEnabled(false);
blueRadioButton->setEnabled(false);
plainTextEdit->setEnabled(false);
okPushButton->setEnabled(false);
}

/*
* 当用户点击取消按钮的槽函数
*/
void MyDialog::onCancelPushButton()
{
underlineCheckBox->setEnabled(true);
italicCheckBox->setEnabled(true);
boldCheckBox->setEnabled(true);
blackRadioButton->setEnabled(true);
redRadioButton->setEnabled(true);
blueRadioButton->setEnabled(true);
plainTextEdit->setEnabled(true);
okPushButton->setEnabled(true);

underlineCheckBox->setChecked(false);  
italicCheckBox->setChecked(false);  
boldCheckBox->setChecked(false);  
blackRadioButton->setChecked(true);  
redRadioButton->setChecked(false);  
blueRadioButton->setChecked(false);

onUnderlineCheckBox(false);  
onItalicCheckBox(false);  
onBoldCheckBox(false);  
setTextFontColor();  

}

main.cpp

#include "mydialog.h"
#include

int main(int argc, char *argv[])
{
QApplication a(argc, argv);
MyDialog w;
w.show();

return a.exec();  

}

效果展示