QWidget 用来构建简单窗口

QMainWindow 用来构建更复杂的窗口，QMainWindow 继承自QWidget，在QWidget 的基础上提供了菜单栏、工具栏、状态栏等功能

• 菜单栏（QMenuBar）
• 工具栏（QToolBar）
• 状态栏（QStatusBar）
• 中央窗口区域（setCentralWidget()）

#include <QAction>
#include <QApplication>
#include <QMainWindow>
#include <QMenuBar>
#include <QMessageBox>class MyWindow : public QMainWindow {
public:MyWindow(){// 创建菜单栏QMenuBar* menuBar = this->menuBar();// 创建菜单QMenu* fileMenu = menuBar->addMenu("File");// 创建菜单项QAction* newAction = new QAction("New", this);QAction* openAction = new QAction("Open", this);QAction* exitAction = new QAction("Exit", this);// 将菜单项添加到菜单中fileMenu->addAction(newAction);fileMenu->addAction(openAction);fileMenu->addSeparator(); // 添加分隔符fileMenu->addAction(exitAction);// 连接信号和槽connect(newAction, &QAction::triggered, this, &MyWindow::newFile);connect(openAction, &QAction::triggered, this, &MyWindow::openFile);connect(exitAction, &QAction::triggered, this, &MyWindow::exitApp);}private:void newFile(){QMessageBox::information(this, "New File", "New file action triggered!");}void openFile(){QMessageBox::information(this, "Open File", "Open file action triggered!");}void exitApp(){QApplication::quit();}
};int main(int argc, char* argv[])
{QApplication app(argc, argv);MyWindow window;window.resize(800, 600);window.show();return app.exec();
}