mainwindow.cpp

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// Copyright (C) 2016 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
 
#include <QtWidgets>
 
#include "mainwindow.h"
MainWindow::MainWindow()
{
    textEdit = new QPlainTextEdit;
    setCentralWidget(textEdit);
 
    createActions();
    createMenus();
    createToolBars();
    createStatusBar();
 
    readSettings();
 
    connect(textEdit->document(), &QTextEdit::contentsChanged,
            this, &QAction::documentWasModified);
 
    setCurrentFile(QString());
    setUnifiedTitleAndToolBarOnMac(true);
}
 
void MainWindow::closeEvent(QCloseEvent *event)
{
    if (maybeSave()) {
        writeSettings();
        event->accept();
    } else {
        event->ignore();
    }
}
 
void MainWindow::newFile()
{
    if (maybeSave()) {
        textEdit->clear();
        setCurrentFile(QString());
    }
}
 
void MainWindow::open()
{
    if (maybeSave()) {
        QString fileName = QFileDialog::getOpenFileName(this);
        if (!fileName.isEmpty())
            loadFile(fileName);
    }
}
 
bool MainWindow::save()
{
    if (curFile.isEmpty()) {
        return saveAs();
    } else {
        return saveFile(curFile);
    }
}
 
bool MainWindow::saveAs()
{
    QString fileName = QFileDialog::getSaveFileName(this);
    if (fileName.isEmpty())
        return false;
 
    return saveFile(fileName);
}
 
void MainWindow::about()
{
   QMessageBox::about(this, tr("About Application"),
            tr("The <b>Application</b> example demonstrates how to "
               "write modern GUI applications using Qt, with a menu bar, "
               "toolbars, and a status bar."));
}
 
void MainWindow::documentWasModified()
{
    setWindowModified(textEdit->document()->isModified());
}
 
void MainWindow::createActions()
{
    newAct = new QAction(QIcon(":/images/new.png"), tr("&New"), this);
    newAct->setShortcuts(QKeySequence::New);
    newAct->setStatusTip(tr("Create a new file"));
    connect(newAct, &QAction::triggered, this, &MainWindow::newFile);
 
    openAct = new QAction(QIcon(":/images/open.png"), tr("&Open..."), this);
    openAct->setShortcuts(QKeySequence::Open);
    openAct->setStatusTip(tr("Open an existing file"));
    connect(openAct, &QAction::triggered, this, &MainWindow::open);
 
    saveAct = new QAction(QIcon(":/images/save.png"), tr("&Save"), this);
    saveAct->setShortcuts(QKeySequence::Save);
    saveAct->setStatusTip(tr("Save the document to disk"));
    connect(saveAct, &QAction::triggered, this, &MainWindow::save);
 
    saveAsAct = new QAction(tr("Save &As..."), this);
    saveAsAct->setShortcuts(QKeySequence::SaveAs);
    saveAsAct->setStatusTip(tr("Save the document under a new name"));
    connect(saveAsAct, &QAction::triggered, this, &MainWindow::saveAs);
 
    exitAct = new QAction(tr("E&xit"), this);
    exitAct->setShortcuts(QKeySequence::Quit);
    exitAct->setStatusTip(tr("Exit the application"));
    connect(exitAct, &QAction::triggered, this, &MainWindow::close);
 
    cutAct = new QAction(QIcon(":/images/cut.png"), tr("Cu&t"), this);
    cutAct->setShortcuts(QKeySequence::Cut);
    cutAct->setStatusTip(tr("Cut the current selection's contents to the "
                            "clipboard"));
    connect(cutAct, &QAction::triggered, textEdit, &QTextEdit::cut);
 
    copyAct = new QAction(QIcon(":/images/copy.png"), tr("&Copy"), this);
    copyAct->setShortcuts(QKeySequence::Copy);
    copyAct->setStatusTip(tr("Copy the current selection's contents to the "
                             "clipboard"));
    connect(copyAct, &QAction::triggered, textEdit, &QTextEdit::copy);
 
    pasteAct = new QAction(QIcon(":/images/paste.png"), tr("&Paste"), this);
    pasteAct->setShortcuts(QKeySequence::Paste);
    pasteAct->setStatusTip(tr("Paste the clipboard's contents into the current "
                              "selection"));
    connect(pasteAct, &QAction::triggered, textEdit, &QTextEdit::paste);
 
    aboutAct = new QAction(tr("&About"), this);
    aboutAct->setStatusTip(tr("Show the application's About box"));
    connect(aboutAct, &QAction::triggered, this, &MainWindow::about);
 
    aboutQtAct = new QAction(tr("About &Qt"), this);
    aboutQtAct->setStatusTip(tr("Show the Qt library's About box"));
    connect(aboutQtAct, &QAction::triggered, qApp, &QApplication::aboutQt);
 
    cutAct->setEnabled(false);
    copyAct->setEnabled(false);
    connect(textEdit, &QTextEdit::copyAvailable,
            cutAct, &QAction::setEnabled);
    connect(textEdit, &QTextEdit::copyAvailable,
            copyAct, &QAction::setEnabled);
}
 
void MainWindow::createMenus()
{
    fileMenu = menuBar()->addMenu(tr("&File"));
    fileMenu->addAction(newAct);
    fileMenu->addAction(openAct);
    fileMenu->addAction(saveAct);
    fileMenu->addAction(saveAsAct);
    fileMenu->addSeparator();
    fileMenu->addAction(exitAct);
 
    editMenu = menuBar()->addMenu(tr("&Edit"));
    editMenu->addAction(cutAct);
    editMenu->addAction(copyAct);
    editMenu->addAction(pasteAct);
 
    menuBar()->addSeparator();
 
    helpMenu = menuBar()->addMenu(tr("&Help"));
    helpMenu->addAction(aboutAct);
    helpMenu->addAction(aboutQtAct);
}
 
void MainWindow::createToolBars()
{
    fileToolBar = addToolBar(tr("File"));
    fileToolBar->addAction(newAct);
    fileToolBar->addAction(openAct);
    fileToolBar->addAction(saveAct);
 
    editToolBar = addToolBar(tr("Edit"));
    editToolBar->addAction(cutAct);
    editToolBar->addAction(copyAct);
    editToolBar->addAction(pasteAct);
}
 
void MainWindow::createStatusBar()
{
    statusBar()->showMessage(tr("Ready"));
}
 
void MainWindow::readSettings()
{
    QSettings settings("QtProject", "Application Example");
    QPoint pos = settings.value("pos", QPoint(200, 200)).toPoint();
    QSize size = settings.value("size", QSize(400, 400)).toSize();
    resize(size);
    move(pos);
}
 
void MainWindow::writeSettings()
{
    QSettings settings("QtProject", "Application Example");
    settings.setValue("pos", pos());
    settings.setValue("size", size());
}
 
bool MainWindow::maybeSave()
{
    if (textEdit->document()->isModified()) {
        QMessageBox::StandardButton ret;
        ret = QMessageBox::warning(this, tr("Application"),
                     tr("The document has been modified.\n"
                        "Do you want to save your changes?"),
                     QMessageBox::Save | QMessageBox::Discard | QMessageBox::Cancel);
        if (ret == QMessageBox::Save)
            return save();
        else if (ret == QMessageBox::Cancel)
            return false;
    }
    return true;
}
 
void MainWindow::loadFile(const QString &fileName)
{
    QFile file(fileName);
    if (!file.open(QFile::ReadOnly | QFile::Text)) {
        QMessageBox::warning(this, tr("Application"),
                             tr("Cannot read file %1:\n%2.")
                             .arg(fileName)
                             .arg(file.errorString()));
        return;
    }
 
    QTextStream in(&file);
#ifndef QT_NO_CURSOR
    QGuiApplication::setOverrideCursor(Qt::WaitCursor);
#endif
    textEdit->setPlainText(in.readAll());
#ifndef QT_NO_CURSOR
    QGuiApplication::restoreOverrideCursor();
#endif
 
    setCurrentFile(fileName);
    statusBar()->showMessage(tr("File loaded"), 2000);
}
 
bool MainWindow::saveFile(const QString &fileName)
{
    QFile file(fileName);
    if (!file.open(QFile::WriteOnly | QFile::Text)) {
        QMessageBox::warning(this, tr("Application"),
                             tr("Cannot write file %1:\n%2.")
                             .arg(fileName)
                             .arg(file.errorString()));
        return false;
    }
 
    QTextStream out(&file);
#ifndef QT_NO_CURSOR
    QGuiApplication::setOverrideCursor(Qt::WaitCursor);
#endif
    out << textEdit->toPlainText();
#ifndef QT_NO_CURSOR
    QGuiApplication::restoreOverrideCursor();
#endif
 
    setCurrentFile(fileName);
    statusBar()->showMessage(tr("File saved"), 2000);
    return true;
}
 
void MainWindow::setCurrentFile(const QString &fileName)
{
    curFile = fileName;
    textEdit->document()->setModified(false);
    setWindowModified(false);
 
    QString shownName = curFile;
    if (curFile.isEmpty())
        shownName = "untitled.txt";
    setWindowFilePath(shownName);
}
 
QString MainWindow::strippedName(const QString &fullFileName)
{
    return QFileInfo(fullFileName).fileName();
}