一个Qt的例子

#define QWDLGMANUAL_H

#include <QDialog>
#include <QCheckBox>
#include <QRadioButton>
#include <QPlainTextEdit>
#include <QPushButton>
class QWDlgManual : public QDialog
{
    Q_OBJECT
private:
    QCheckBox   *chkBoxUnder;
    QCheckBox   *chkBoxItalic;
    QCheckBox   *chkBoxBold;
    QRadioButton    *rBtnBlack;
    QRadioButton    *rBtnRed;
    QRadioButton    *rBtnBlue;
    QPlainTextEdit  *txtEdit;
    QPushButton     *btnOK;
    QPushButton     *btnCancel;
    QPushButton     *btnClose;
    void    iniUI();//UI 创建与初始化
    void    iniSignalSlots();//初始化信号与槽的链接
private slots:
    void on_chkBoxUnder(bool checked); //Underline 的clicked(bool)信号的槽函数
    void on_chkBoxItalic(bool checked);//Italic 的clicked(bool)信号的槽函数
    void on_chkBoxBold(bool checked); //Bold 的clicked(bool)信号的槽函数
    void setTextFontColor(); //设置字体颜色
public:
    QWDlgManual(QWidget *parent = 0);
    ~QWDlgManual();
};

#endif // QWDLGMANUAL_H


#include "qwdlgmanual.h"
#include <QHBoxLayout>
QWDlgManual::QWDlgManual(QWidget *parent)
    : QDialog(parent)
{
    iniUI(); //界面创建与布局
    iniSignalSlots(); //信号与槽的关联
    setWindowTitle("Form created mannually");
}

QWDlgManual::~QWDlgManual()
{

}
void QWDlgManual::on_chkBoxUnder(bool checked)
{
    QFont font=txtEdit->font();
    font.setUnderline(checked);
    txtEdit->setFont(font);
}
void QWDlgManual::on_chkBoxItalic(bool checked)
{
    QFont font = txtEdit->font();
    font.setItalic(checked);
    txtEdit->setFont(font);

}
void QWDlgManual::on_chkBoxBold(bool checked)
{
    QFont font = txtEdit->font();
    font.setBold(checked);
    txtEdit->setFont(font);


}

void QWDlgManual::setTextFontColor()
{

        QPalette plet=txtEdit->palette();
        if (rBtnBlue->isChecked())
            plet.setColor(QPalette::Text,Qt::blue);
        else if (rBtnRed->isChecked())
           plet.setColor(QPalette::Text,Qt::red);
        else if (rBtnBlack->isChecked())
            plet.setColor(QPalette::Text,Qt::black);
        else
           plet.setColor(QPalette::Text,Qt::black);

        txtEdit->setPalette(plet);

}
void QWDlgManual::iniUI()
{
    //创建 Underline, Italic, Bold 3 个CheckBox，并水平布局
    chkBoxUnder=new QCheckBox(tr("Underline"));
    chkBoxItalic=new QCheckBox(tr("Italic"));
    chkBoxBold=new QCheckBox(tr("Bold"));
    QHBoxLayout *HLay1=new QHBoxLayout;
    HLay1->addWidget(chkBoxUnder);
    HLay1->addWidget(chkBoxItalic);
    HLay1->addWidget(chkBoxBold);
    //创建 Black, Red, Blue 3 个RadioButton，并水平布局
    rBtnBlack=new QRadioButton(tr("Black"));
    rBtnBlack->setChecked(true);
    rBtnRed=new QRadioButton(tr("Red"));
    rBtnBlue=new QRadioButton(tr("Blue"));
    QHBoxLayout *HLay2=new QHBoxLayout;
    HLay2->addWidget(rBtnBlack);
    HLay2->addWidget(rBtnRed);
    HLay2->addWidget(rBtnBlue);
    //创建确定, 取消, 退出3 个 PushButton, 并水平布局
    btnOK=new QPushButton(tr("确定"));
    btnCancel=new QPushButton(tr("取消"));
    btnClose=new QPushButton(tr("退出"));
    QHBoxLayout *HLay3=new QHBoxLayout;
    HLay3->addStretch();
    HLay3->addWidget(btnOK);
    HLay3->addWidget(btnCancel);
    HLay3->addStretch();
    HLay3->addWidget(btnClose);
    //创建文本框,并设置初始字体
    txtEdit=new QPlainTextEdit;
    txtEdit->setPlainText("Hello world\n\nIt is my demo");
    QFont font=txtEdit->font(); //获取字体
    font.setPointSize(20);//修改字体大小
    txtEdit->setFont(font);//设置字体
    //创建垂直布局，并设置为主布局
    QVBoxLayout *VLay=new QVBoxLayout;
    VLay->addLayout(HLay1); //添加字体类型组
    VLay->addLayout(HLay2);//添加字体颜色组
    VLay->addWidget(txtEdit);//添加PlainTextEdit
    VLay->addLayout(HLay3);//添加按键组
    setLayout(VLay); //设置为窗体的主布局
}

void QWDlgManual::iniSignalSlots()
{
    //三个颜色 QRadioButton 的clicked()信号与setTextFontColor()槽函数关联
    connect(rBtnBlue,SIGNAL(clicked()),this,SLOT(setTextFontColor()));
    connect(rBtnRed,SIGNAL(clicked()),this,SLOT(setTextFontColor()));
    connect(rBtnBlack,SIGNAL(clicked()),this,SLOT(setTextFontColor()));
    //三个字体设置的 QCheckBox 的clicked(bool)信号与相应的槽函数关联
    connect(chkBoxUnder,SIGNAL(clicked(bool)),
    this,SLOT(on_chkBoxUnder(bool)));
    connect(chkBoxItalic,SIGNAL(clicked(bool)),
    this,SLOT(on_chkBoxItalic(bool)));
    connect(chkBoxBold,SIGNAL(clicked(bool)),
    this,SLOT(on_chkBoxBold(bool)));
    //三个按钮的信号与窗体的槽函数关联
    connect(btnOK,SIGNAL(clicked()),this,SLOT(accept()));
    connect(btnCancel,SIGNAL(clicked()),this,SLOT(reject()));
    connect(btnClose,SIGNAL(clicked()),this,SLOT(close()));
}

#include "qwdlgmanual.h"
#include <QApplication>

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

    return a.exec();
}