QT new project_ MyNotepad++

How to create a menu bar

Hold down alt+F You can choose file (F)

The creation is successful, as shown in the figure below :

According to the above method, we create the effect of the following figure in turn

Yes Create new functions to expand

Function description :
When textEdit That text box Change when , Click New At the terminal output Prompt information .

Realization effect

Implementation code

mainwindow.h

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QMainWindow>
#include <QMessageBox>
#include <QDebug>

QT_BEGIN_NAMESPACE
namespace Ui {
     class MainWindow; }
QT_END_NAMESPACE

class MainWindow : public QMainWindow
{
    
    Q_OBJECT

public:
    MainWindow(QWidget *parent = nullptr);
    ~MainWindow();

private:
    Ui::MainWindow *ui;
private slots:
    void newFileSlot();
};
#endif // MAINWINDOW_H

main.cpp

#include "mainwindow.h"

#include <QApplication>

int main(int argc, char *argv[])
{
    
    QApplication a(argc, argv);
    MainWindow w;
    w.show();
    return a.exec();
}

mainwindow.cpp

#include "mainwindow.h"
#include "ui_mainwindow.h"

MainWindow::MainWindow(QWidget *parent)
    : QMainWindow(parent)
    , ui(new Ui::MainWindow)
{
    
    ui->setupUi(this);
    // Set title 
    this->setWindowTitle("ning_ning_WenDang");
    QObject::connect(
                ui->newAction,
                SIGNAL(triggered()),
                this,
                SLOT(newFileSlot())
                );
}

MainWindow::~MainWindow()
{
    
    delete ui;
}

void MainWindow::newFileSlot()
{
    
    // If the current document has changed 
    if(ui->textEdit->document()->isModified())
    {
    
        qDebug()<<"current file modified."; // Current document changes ;
    }
    else
    {
    
        qDebug()<<"not modified.";
    }
}