QT5的一个小例程编写一个简单的文本文件编辑器，

#include <QtGui> #include <QtWidgets> #include "mainwindow.h" MainWindow::MainWindow(QWidget *parent) : QMainWindow(parent) { openAction = new QAction(QIcon(":/images/file-open"), tr("&Open..."), this); openAction->setShortcuts(QKeySequence::Open); openAction->setStatusTip(tr("Open an existing file")); connect(openAction, &QAction::triggered, this, &MainWindow::openFile); saveAction = new QAction(QIcon(":/images/file-save"), tr("&Save..."), this); saveAction->setShortcuts(QKeySequence::Save); saveAction->setStatusTip(tr("Save a new file")); connect(saveAction, &QAction::triggered, this, &MainWindow::saveFile); QMenu *file = menuBar()->addMenu(tr("&File")); file->addAction(openAction); file->addAction(saveAction); QToolBar *toolBar = addToolBar(tr("&File")); toolBar->addAction(openAction); toolBar->addAction(saveAction); textEdit = new QTextEdit(this); setCentralWidget(textEdit); } MainWindow::~MainWindow() { } void MainWindow::openFile() { QString path = QFileDialog::getOpenFileName(this, tr("Open File"), ".", tr("Text Files(*.txt)")); if(!path.isEmpty()) { QFile file(path); if (!file.open(QIODevice::ReadOnly | QIODevice::Text)) { QMessageBox::warning(this, tr("Read File"), tr("Cannot open file:\n%1").arg(path)); return; } QTextStream in(&file); textEdit->setText(in.readAll()); file.close(); } else { QMessageBox::warning(this, tr("Path"), tr("You did not select any file.")); } } void MainWindow::saveFile() { QString path = QFileDialog::getSaveFileName(this, tr("Save File"), ".", tr("Text Files(*.txt)")); if(!path.isEmpty()) { QFile file(path); if (!file.open(QIODevice::WriteOnly | QIODevice::Text)) { QMessageBox::warning(this, tr("Write File"), tr("Cannot open file:\n%1").arg(path)); return; } QTextStream out(&file); out << textEdit->toPlainText(); file.close(); } else { QMessageBox::warning(this, tr("Path"), tr("You did not select any file.")); } }