mainwindow.h

#ifndef MAINWINDOW_H
#define MAINWINDOW_H#include <QMainWindow>QT_BEGIN_NAMESPACE //命名空间
namespace Ui { class MainWindow; } //ui_MainWindow文件里定义的类，外部声明
QT_END_NAMESPACEclass MainWindow : public QMainWindow
{Q_OBJECT //宏，使用QT信号和槽机制必须添加public:MainWindow(QWidget *parent = nullptr);~MainWindow();private slots:void on_pushButton_clicked();private:Ui::MainWindow *ui; //Ui::Widget类型的一个指针，指向可视化的界面
};
#endif // MAINWINDOW_H

main.cpp

```bash
#include "mainwindow.h"
#include <QApplication>int main(int argc, char *argv[])
{QApplication a(argc, argv); //定义并创建应用程序 MainWindow w; //定义并创建窗口w.show(); //窗口显示return a.exec(); //应用程序运行，开始消息循环和事件处理
}

mainwindow.cpp

#include "mainwindow.h"
#include "ui_mainwindow.h"MainWindow::MainWindow(QWidget *parent): QMainWindow(parent), ui(new Ui::MainWindow)
{ui->setupUi(this); //实现了组件的各种设置，信号和槽的关联
}MainWindow::~MainWindow()
{delete ui; //析构函数
}void MainWindow::on_pushButton_clicked()
{ui->pushButton\
}

写一个简单的QT ui 程序

#ifndef DIALOG_H
#define DIALOG_H#include <QDialog>QT_BEGIN_NAMESPACE
namespace Ui { class Dialog; }
QT_END_NAMESPACEclass Dialog : public QDialog
{Q_OBJECTpublic:Dialog(QWidget *parent = nullptr);~Dialog();private slots://void on_PBCancel_clicked();//void on_checkBox_stateChanged(int arg1);//void on_checkBox_clicked(bool checked);//void on_plainTextEdit_textChanged();void on_underline_clicked(bool checkd); //构建控件函数的时候记得在头文件中声明完整的控件函数（包括传入参数）void on_italic_clicked(bool checked);void on_bold_clicked(bool checked);void setTextFontColor();private:Ui::Dialog *ui;
};
#endif // DIALOG_H

#include "dialog.h"
#include "ui_dialog.h"Dialog::Dialog(QWidget *parent): QDialog(parent), ui(new Ui::Dialog)
{ui->setupUi(this);QObject::connect(ui->rBtnRed,SIGNAL(clicked()),this,SLOT(setTextFontColor()));QObject::connect(ui->rBtnBlue,SIGNAL(clicked()),this,SLOT(setTextFontColor()));QObject::connect(ui->rBtnBlack,SIGNAL(clicked()),this,SLOT(setTextFontColor()));}Dialog::~Dialog()
{delete ui;
}//调整控件后记得重新构建，构建控件函数的时候记得在头文件中声明完整的控件函数（包括传入参数）void Dialog::on_underline_clicked(bool checked)
{QFont font = ui->plainTextEdit->font();font.setUnderline(checked);ui->plainTextEdit->setFont(font);
}void Dialog::on_italic_clicked(bool checked)
{QFont font = ui->plainTextEdit->font();font.setItalic(checked);ui->plainTextEdit->setFont(font);
}void Dialog::on_bold_clicked(bool checked)
{QFont font = ui->plainTextEdit->font();font.setBold(checked);ui->plainTextEdit->setFont(font);
}void Dialog::setTextFontColor()
{QPalette plet = ui->plainTextEdit->palette();if(ui->rBtnBlack->isChecked())plet.setColor(QPalette::Text,Qt::black);else if(ui->rBtnBlue->isChecked())plet.setColor(QPalette::Text,Qt::blue);else if(ui->rBtnRed->isChecked())plet.setColor(QPalette::Text,Qt::red);elseplet.setColor(QPalette::Text,Qt::black);ui->plainTextEdit->setPalette(plet);}