记事本代码：
“mainwindow.h”
#ifndef MAINWINDOW_H
#define MAINWINDOW_H
#include <QMainWindow>
#include <QMessageBox>
#include <QtDebug>
#include <QFile>
#include <QFileDialog>
#include <QDir>
#include <QTextStream>
#include <QFont>
#include <QFontDialog>
#include <QColor>
#include <QColorDialog>
#include <QDateTime>
#include <QAction>
namespace Ui {
class MainWindow;
}
class MainWindow : public QMainWindow
{
Q_OBJECT
public:
explicit MainWindow(QWidget *parent = 0);
~MainWindow();
private:
Ui::MainWindow *ui;
QString fileName;
private slots:
// void newFileSlot();
// void openFileSlot();
void newFileSlot();
void openFileSlot();
void saveFileSlot();
void saveAsFileSlot();
// void undoSlot();
// void redoSlot();
// void copySlot();
// void cutSlot();
// void pasteSlot();
// void seleteAllSlot();
void setFontSlot();
void setColorSlot();
void currentDateTimeSlot();
};
#endif // MAINWINDOW_H
“main.cpp”
#include <QtGui/QApplication>
#include "mainwindow.h"
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);
this->setWindowTitle("Untitled-notepad");
QObject::connect(ui->newAction,SIGNAL(triggered()),this,SLOT(newFileSlot()));
QObject::connect(ui->openAction,SIGNAL(triggered()),this,SLOT(openFileSlot()));
QObject::connect(ui->saveAction,SIGNAL(triggered()),this,SLOT(saveFileSlot()));
QObject::connect(ui->saveAsAction,SIGNAL(triggered()),this,SLOT(saveAsFileSlot()));
QObject::connect(ui->exitAction,SIGNAL(triggered()),this,SLOT(close()));
// QObject::connect(ui->copyAction,SIGNAL(triggered()),this,SLOT(copySlot()));
// QObject::connect(ui->seleteAllAction,SIGNAL(triggered()),this,SLOT(seleteAllSlot()));
// QObject::connect(ui->cutAction,SIGNAL(triggered()),this,SLOT(cutSlot()));
// QObject::connect(ui->pasteAction,SIGNAL(triggered()),this,SLOT(pasteSlot()));
// QObject::connect(ui->undoAction,SIGNAL(triggered()),this,SLOT(undoSlot()));
// QObject::connect(ui->redoAction,SIGNAL(triggered()),this,SLOT(redoSlot()));
QObject::connect(ui->copyAction,SIGNAL(triggered()),ui->textEdit,SLOT(copy()));
QObject::connect(ui->seleteAllAction,SIGNAL(triggered()),ui->textEdit,SLOT(selectAll()));
QObject::connect(ui->cutAction,SIGNAL(triggered()),ui->textEdit,SLOT(cut()));
QObject::connect(ui->pasteAction,SIGNAL(triggered()),ui->textEdit,SLOT(paste()));
QObject::connect(ui->undoAction,SIGNAL(triggered()),ui->textEdit,SLOT(undo()));
QObject::connect(ui->redoAction,SIGNAL(triggered()),ui->textEdit,SLOT(redo()));
QObject::connect(ui->colorAction,SIGNAL(triggered()),this,SLOT(setColorSlot()));
QObject::connect(ui->FontAction,SIGNAL(triggered()),this,SLOT(setFontSlot()));
QObject::connect(ui->dateTimeAction,SIGNAL(triggered()),this,SLOT(currentDateTimeSlot()));
}
MainWindow::~MainWindow()
{
delete ui;
}
void MainWindow::newFileSlot()
{
if (ui->textEdit->document()->isModified())
{
qDebug() << "current file modified";
}
else
{
ui->textEdit->clear();
this->setWindowTitle("Untitled.txt");
}
}
void MainWindow::openFileSlot()
{
fileName = QFileDialog::getOpenFileName(this,"Open File",QDir::currentPath());
if (fileName.isEmpty())
{
QMessageBox::information(this,"ERROR MESSAGE","Please selete a file");
return;
}
QFile *file = new QFile;
file->setFileName(fileName);
bool ok = file->open(QIODevice::ReadOnly);
if (ok)
{
QTextStream in(file);
ui->textEdit->setText(in.readAll());
file->close();
delete file;
}
else
{
QMessageBox::warning(this,"ERROR MESSAGE","File Open FiLE"+file->errorString());
return;
}
}
void MainWindow::saveFileSlot()
{
//QString fileName = ui->textEdit->QDir::currentPath();//QFileDialog::getOpenFileName(this,"Save File",QDir::currentPath());
if (fileName.isEmpty())
{
saveAsFileSlot();
}
else
{
QFile *file = new QFile;
file->setFileName(fileName);
bool ok = file->open(QIODevice::WriteOnly);
if (ok)
{
QTextStream out(file);
out << ui->textEdit->toPlainText();
file->close();
delete file;
}
else
{
QMessageBox::information(this,"ERROR MESSAGE","save file error");
return;
}
}
}
void MainWindow::saveAsFileSlot()
{
QString AnotherFileName = QFileDialog::getSaveFileName(this,"save as Another",QDir::currentPath());
if (AnotherFileName.isEmpty())
{
QMessageBox::warning(this,"ERROR MESSAGE","selete a file");
return;
}
else
{
QFile *file = new QFile;
file->setFileName(AnotherFileName);
bool ok = file->open(QIODevice::WriteOnly);
if (ok)
{
QTextStream out(file);
out << ui->textEdit->toPlainText();
file->close();
delete file;
}
else
{
QMessageBox::warning(this,"ERROR MESSAGE","save file Error");
return;
}
}
}
/*
void MainWindow::undoSlot()
{
ui->textEdit->undo();
}
void MainWindow::redoSlot()
{
ui->textEdit->redo();
}
void MainWindow::copySlot()
{
ui->textEdit->copy();
}
void MainWindow::cutSlot()
{
ui->textEdit->cut();
}
void MainWindow::pasteSlot()
{
ui->textEdit->paste();
}
void MainWindow::seleteAllSlot()
{
ui->textEdit->selectAll();
}
*/
void MainWindow::setFontSlot()
{
bool ok;
QFont font = QFontDialog::getFont(&ok,this);
if (ok)
{
ui->textEdit->setFont(font);
}
else
{
QMessageBox::information(this,"Error Message","Error Set Font!!");
return;
}
}
void MainWindow::setColorSlot()
{
QColor color = QColorDialog::getColor(Qt::red,this);
if (color.isValid())
{
ui->textEdit->setTextColor(color);
}
else
{
QMessageBox::information(this,"Error Message","Color is Unvalid");
return;
}
}
void MainWindow::currentDateTimeSlot()
{
QDateTime current = QDateTime::currentDateTime();
QString time = current.toString("yyyy-MM-dd hh:mm:ss");
ui->textEdit->append(time);
}
四则运算计算器代码：
“mainwindow.h”
#ifndef MAINWINDOW_H
#define MAINWINDOW_H
#include <QMainWindow>
#include <QMessageBox>
namespace Ui {
class MainWindow;
}
class MainWindow : public QMainWindow
{
Q_OBJECT
public:
explicit MainWindow(QWidget *parent = 0);
~MainWindow();
private:
Ui::MainWindow *ui;
private slots:
void calSlot();
};
#endif // MAINWINDOW_H
“mian.cpp”
#include <QtGui/QApplication>
#include "mainwindow.h"
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);
QObject::connect(ui->calButton,SIGNAL(clicked()),this,SLOT(calSlot()));
}
MainWindow::~MainWindow()
{
delete ui;
}
void MainWindow::calSlot()
{
int firth = ui->firstLineEdit->text().toInt();
int second = ui->secondLineEdit->text().toInt();
int result;
if (ui->comboBox->currentIndex() == 0)
{
result = firth + second;
ui->resultLineEdit->setText(QString::number(result));
QMessageBox::information(this,"RESULT:",QString::number(result));
}
else if (ui->comboBox->currentIndex() == 1)
{
result = firth - second;
ui->resultLineEdit->setText(QString::number(result));
QMessageBox::information(this,"RESULT:",QString::number(result));
}
else if (ui->comboBox->currentIndex() == 2)
{
result = firth * second;
ui->resultLineEdit->setText(QString::number(result));
QMessageBox::information(this,"RESULT:",QString::number(result));
}
else
{
if (second == 0)
{
QMessageBox::warning(this,"ERROR MESSAGE:","secondValue can't be zero!");
return;
}
else
{
result = firth / second;
ui->resultLineEdit->setText(QString::number(result));
QMessageBox::information(this,"RESULT:",QString::number(result));
}
}
}