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# textedit.cpp Example File
demos/textedit/textedit.cpp

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     #include "textedit.h"

     #include <QAction>
     #include <QApplication>
     #include <QClipboard>
     #include <QColorDialog>
     #include <QComboBox>
     #include <QFontComboBox>
     #include <QFile>
     #include <QFileDialog>
     #include <QFileInfo>
     #include <QFontDatabase>
     #include <QMenu>
     #include <QMenuBar>
     #include <QPrintDialog>
     #include <QPrinter>
     #include <QTextCodec>
     #include <QTextEdit>
     #include <QToolBar>
     #include <QTextCursor>
     #include <QTextList>
     #include <QtDebug>
     #include <QCloseEvent>
     #include <QMessageBox>
     #include <QPrintPreviewDialog>

     #ifdef Q_WS_MAC
     const QString rsrcPath = ":/images/mac";
     #else
     const QString rsrcPath = ":/images/win";
     #endif

     TextEdit::TextEdit(QWidget *parent)
         : QMainWindow(parent)
     {
         setupFileActions();
         setupEditActions();
         setupTextActions();

         {
             QMenu *helpMenu = new QMenu(tr("Help"), this);
             menuBar()->addMenu(helpMenu);
             helpMenu->addAction(tr("About"), this, SLOT(about()));
             helpMenu->addAction(tr("About &Qt"), qApp, SLOT(aboutQt()));
         }

         textEdit = new QTextEdit(this);
         connect(textEdit, SIGNAL(currentCharFormatChanged(const QTextCharFormat &)),
                 this, SLOT(currentCharFormatChanged(const QTextCharFormat &)));
         connect(textEdit, SIGNAL(cursorPositionChanged()),
                 this, SLOT(cursorPositionChanged()));

         setCentralWidget(textEdit);
         textEdit->setFocus();
         setCurrentFileName(QString());

         fontChanged(textEdit->font());
         colorChanged(textEdit->textColor());
         alignmentChanged(textEdit->alignment());

         connect(textEdit->document(), SIGNAL(modificationChanged(bool)),
                 actionSave, SLOT(setEnabled(bool)));
         connect(textEdit->document(), SIGNAL(modificationChanged(bool)),
                 this, SLOT(setWindowModified(bool)));
         connect(textEdit->document(), SIGNAL(undoAvailable(bool)),
                 actionUndo, SLOT(setEnabled(bool)));
         connect(textEdit->document(), SIGNAL(redoAvailable(bool)),
                 actionRedo, SLOT(setEnabled(bool)));

         setWindowModified(textEdit->document()->isModified());
         actionSave->setEnabled(textEdit->document()->isModified());
         actionUndo->setEnabled(textEdit->document()->isUndoAvailable());
         actionRedo->setEnabled(textEdit->document()->isRedoAvailable());

         connect(actionUndo, SIGNAL(triggered()), textEdit, SLOT(undo()));
         connect(actionRedo, SIGNAL(triggered()), textEdit, SLOT(redo()));

         actionCut->setEnabled(false);
         actionCopy->setEnabled(false);

         connect(actionCut, SIGNAL(triggered()), textEdit, SLOT(cut()));
         connect(actionCopy, SIGNAL(triggered()), textEdit, SLOT(copy()));
         connect(actionPaste, SIGNAL(triggered()), textEdit, SLOT(paste()));

         connect(textEdit, SIGNAL(copyAvailable(bool)), actionCut, SLOT(setEnabled(bool)));
         connect(textEdit, SIGNAL(copyAvailable(bool)), actionCopy, SLOT(setEnabled(bool)));

         connect(QApplication::clipboard(), SIGNAL(dataChanged()), this, SLOT(clipboardDataChanged()));

         QString initialFile = ":/example.html";
         const QStringList args = QCoreApplication::arguments();
         if (args.count() == 2)
             initialFile = args.at(1);

         if (!load(initialFile))
             fileNew();
     }

     void TextEdit::closeEvent(QCloseEvent *e)
     {
         if (maybeSave())
             e->accept();
         else
             e->ignore();
     }

     void TextEdit::setupFileActions()
     {
         QToolBar *tb = new QToolBar(this);
         tb->setWindowTitle(tr("File Actions"));
         addToolBar(tb);

         QMenu *menu = new QMenu(tr("&File"), this);
         menuBar()->addMenu(menu);

         QAction *a;

         a = new QAction(QIcon(rsrcPath + "/filenew.png"), tr("&New"), this);
         a->setShortcut(QKeySequence::New);
         connect(a, SIGNAL(triggered()), this, SLOT(fileNew()));
         tb->addAction(a);
         menu->addAction(a);

         a = new QAction(QIcon(rsrcPath + "/fileopen.png"), tr("&Open..."), this);
         a->setShortcut(QKeySequence::Open);
         connect(a, SIGNAL(triggered()), this, SLOT(fileOpen()));
         tb->addAction(a);
         menu->addAction(a);

         menu->addSeparator();

         actionSave = a = new QAction(QIcon(rsrcPath + "/filesave.png"), tr("&Save"), this);
         a->setShortcut(QKeySequence::Save);
         connect(a, SIGNAL(triggered()), this, SLOT(fileSave()));
         a->setEnabled(false);
         tb->addAction(a);
         menu->addAction(a);

         a = new QAction(tr("Save &As..."), this);
         connect(a, SIGNAL(triggered()), this, SLOT(fileSaveAs()));
         menu->addAction(a);
         menu->addSeparator();

         a = new QAction(QIcon(rsrcPath + "/fileprint.png"), tr("&Print..."), this);
         a->setShortcut(QKeySequence::Print);
         connect(a, SIGNAL(triggered()), this, SLOT(filePrint()));
         tb->addAction(a);
         menu->addAction(a);

         a = new QAction(QIcon(rsrcPath + "/fileprint.png"), tr("Print Preview..."), this);
         connect(a, SIGNAL(triggered()), this, SLOT(filePrintPreview()));
         menu->addAction(a);

         a = new QAction(QIcon(rsrcPath + "/exportpdf.png"), tr("&Export PDF..."), this);
         a->setShortcut(Qt::CTRL + Qt::Key_D);
         connect(a, SIGNAL(triggered()), this, SLOT(filePrintPdf()));
         tb->addAction(a);
         menu->addAction(a);

         menu->addSeparator();

         a = new QAction(tr("&Quit"), this);
         a->setShortcut(Qt::CTRL + Qt::Key_Q);
         connect(a, SIGNAL(triggered()), this, SLOT(close()));
         menu->addAction(a);
     }

     void TextEdit::setupEditActions()
     {
         QToolBar *tb = new QToolBar(this);
         tb->setWindowTitle(tr("Edit Actions"));
         addToolBar(tb);

         QMenu *menu = new QMenu(tr("&Edit"), this);
         menuBar()->addMenu(menu);

         QAction *a;
         a = actionUndo = new QAction(QIcon(rsrcPath + "/editundo.png"), tr("&Undo"), this);
         a->setShortcut(QKeySequence::Undo);
         tb->addAction(a);
         menu->addAction(a);
         a = actionRedo = new QAction(QIcon(rsrcPath + "/editredo.png"), tr("&Redo"), this);
         a->setShortcut(QKeySequence::Redo);
         tb->addAction(a);
         menu->addAction(a);
         menu->addSeparator();
         a = actionCut = new QAction(QIcon(rsrcPath + "/editcut.png"), tr("Cu&t"), this);
         a->setShortcut(QKeySequence::Cut);
         tb->addAction(a);
         menu->addAction(a);
         a = actionCopy = new QAction(QIcon(rsrcPath + "/editcopy.png"), tr("&Copy"), this);
         a->setShortcut(QKeySequence::Copy);
         tb->addAction(a);
         menu->addAction(a);
         a = actionPaste = new QAction(QIcon(rsrcPath + "/editpaste.png"), tr("&Paste"), this);
         a->setShortcut(QKeySequence::Paste);
         tb->addAction(a);
         menu->addAction(a);
         actionPaste->setEnabled(!QApplication::clipboard()->text().isEmpty());
     }

     void TextEdit::setupTextActions()
     {
         QToolBar *tb = new QToolBar(this);
         tb->setWindowTitle(tr("Format Actions"));
         addToolBar(tb);

         QMenu *menu = new QMenu(tr("F&ormat"), this);
         menuBar()->addMenu(menu);

         actionTextBold = new QAction(QIcon(rsrcPath + "/textbold.png"), tr("&Bold"), this);
         actionTextBold->setShortcut(Qt::CTRL + Qt::Key_B);
         QFont bold;
         bold.setBold(true);
         actionTextBold->setFont(bold);
         connect(actionTextBold, SIGNAL(triggered()), this, SLOT(textBold()));
         tb->addAction(actionTextBold);
         menu->addAction(actionTextBold);
         actionTextBold->setCheckable(true);

         actionTextItalic = new QAction(QIcon(rsrcPath + "/textitalic.png"), tr("&Italic"), this);
         actionTextItalic->setShortcut(Qt::CTRL + Qt::Key_I);
         QFont italic;
         italic.setItalic(true);
         actionTextItalic->setFont(italic);
         connect(actionTextItalic, SIGNAL(triggered()), this, SLOT(textItalic()));
         tb->addAction(actionTextItalic);
         menu->addAction(actionTextItalic);
         actionTextItalic->setCheckable(true);

         actionTextUnderline = new QAction(QIcon(rsrcPath + "/textunder.png"), tr("&Underline"), this);
         actionTextUnderline->setShortcut(Qt::CTRL + Qt::Key_U);
         QFont underline;
         underline.setUnderline(true);
         actionTextUnderline->setFont(underline);
         connect(actionTextUnderline, SIGNAL(triggered()), this, SLOT(textUnderline()));
         tb->addAction(actionTextUnderline);
         menu->addAction(actionTextUnderline);
         actionTextUnderline->setCheckable(true);

         menu->addSeparator();

         QActionGroup *grp = new QActionGroup(this);
         connect(grp, SIGNAL(triggered(QAction *)), this, SLOT(textAlign(QAction *)));

         actionAlignLeft = new QAction(QIcon(rsrcPath + "/textleft.png"), tr("&Left"), grp);
         actionAlignLeft->setShortcut(Qt::CTRL + Qt::Key_L);
         actionAlignLeft->setCheckable(true);
         actionAlignCenter = new QAction(QIcon(rsrcPath + "/textcenter.png"), tr("C&enter"), grp);
         actionAlignCenter->setShortcut(Qt::CTRL + Qt::Key_E);
         actionAlignCenter->setCheckable(true);
         actionAlignRight = new QAction(QIcon(rsrcPath + "/textright.png"), tr("&Right"), grp);
         actionAlignRight->setShortcut(Qt::CTRL + Qt::Key_R);
         actionAlignRight->setCheckable(true);
         actionAlignJustify = new QAction(QIcon(rsrcPath + "/textjustify.png"), tr("&Justify"), grp);
         actionAlignJustify->setShortcut(Qt::CTRL + Qt::Key_J);
         actionAlignJustify->setCheckable(true);

         tb->addActions(grp->actions());
         menu->addActions(grp->actions());

         menu->addSeparator();

         QPixmap pix(16, 16);
         pix.fill(Qt::black);
         actionTextColor = new QAction(pix, tr("&Color..."), this);
         connect(actionTextColor, SIGNAL(triggered()), this, SLOT(textColor()));
         tb->addAction(actionTextColor);
         menu->addAction(actionTextColor);

         tb = new QToolBar(this);
         tb->setAllowedAreas(Qt::TopToolBarArea | Qt::BottomToolBarArea);
         tb->setWindowTitle(tr("Format Actions"));
         addToolBarBreak(Qt::TopToolBarArea);
         addToolBar(tb);

         comboStyle = new QComboBox(tb);
         tb->addWidget(comboStyle);
         comboStyle->addItem("Standard");
         comboStyle->addItem("Bullet List (Disc)");
         comboStyle->addItem("Bullet List (Circle)");
         comboStyle->addItem("Bullet List (Square)");
         comboStyle->addItem("Ordered List (Decimal)");
         comboStyle->addItem("Ordered List (Alpha lower)");
         comboStyle->addItem("Ordered List (Alpha upper)");
         connect(comboStyle, SIGNAL(activated(int)),
                 this, SLOT(textStyle(int)));

         comboFont = new QFontComboBox(tb);
         tb->addWidget(comboFont);
         connect(comboFont, SIGNAL(activated(const QString &)),
                 this, SLOT(textFamily(const QString &)));

         comboSize = new QComboBox(tb);
         comboSize->setObjectName("comboSize");
         tb->addWidget(comboSize);
         comboSize->setEditable(true);

         QFontDatabase db;
         foreach(int size, db.standardSizes())
             comboSize->addItem(QString::number(size));

         connect(comboSize, SIGNAL(activated(const QString &)),
                 this, SLOT(textSize(const QString &)));
         comboSize->setCurrentIndex(comboSize->findText(QString::number(QApplication::font()
                                                                        .pointSize())));
     }

     bool TextEdit::load(const QString &f)
     {
         if (!QFile::exists(f))
             return false;
         QFile file(f);
         if (!file.open(QFile::ReadOnly))
             return false;

         QByteArray data = file.readAll();
         QTextCodec *codec = Qt::codecForHtml(data);
         QString str = codec->toUnicode(data);
         if (Qt::mightBeRichText(str)) {
             textEdit->setHtml(str);
         } else {
             str = QString::fromLocal8Bit(data);
             textEdit->setPlainText(str);
         }

         setCurrentFileName(f);
         return true;
     }

     bool TextEdit::maybeSave()
     {
         if (!textEdit->document()->isModified())
             return true;
         if (fileName.startsWith(QLatin1String(":/")))
             return true;
         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 fileSave();
         else if (ret == QMessageBox::Cancel)
             return false;
         return true;
     }

     void TextEdit::setCurrentFileName(const QString &fileName)
     {
         this->fileName = fileName;
         textEdit->document()->setModified(false);

         QString shownName;
         if (fileName.isEmpty())
             shownName = "untitled.txt";
         else
             shownName = QFileInfo(fileName).fileName();

         setWindowTitle(tr("%1[*] - %2").arg(shownName).arg(tr("Rich Text")));
         setWindowModified(false);
     }

     void TextEdit::fileNew()
     {
         if (maybeSave()) {
             textEdit->clear();
             setCurrentFileName(QString());
         }
     }

     void TextEdit::fileOpen()
     {
         QString fn = QFileDialog::getOpenFileName(this, tr("Open File..."),
                                                   QString(), tr("HTML-Files (*.htm *.html);;All Files (*)"));
         if (!fn.isEmpty())
             load(fn);
     }

     bool TextEdit::fileSave()
     {
         if (fileName.isEmpty())
             return fileSaveAs();

         QFile file(fileName);
         if (!file.open(QFile::WriteOnly))
             return false;
         QTextStream ts(&file);
         ts.setCodec(QTextCodec::codecForName("UTF-8"));
         ts << textEdit->document()->toHtml("UTF-8");
         textEdit->document()->setModified(false);
         return true;
     }

     bool TextEdit::fileSaveAs()
     {
         QString fn = QFileDialog::getSaveFileName(this, tr("Save as..."),
                                                   QString(), tr("HTML-Files (*.htm *.html);;All Files (*)"));
         if (fn.isEmpty())
             return false;
         setCurrentFileName(fn);
         return fileSave();
     }

     void TextEdit::filePrint()
     {
     #ifndef QT_NO_PRINTER
         QPrinter printer(QPrinter::HighResolution);
         printer.setFullPage(true);
         QPrintDialog *dlg = new QPrintDialog(&printer, this);
         if (textEdit->textCursor().hasSelection())
             dlg->addEnabledOption(QAbstractPrintDialog::PrintSelection);
         dlg->setWindowTitle(tr("Print Document"));
         if (dlg->exec() == QDialog::Accepted) {
             textEdit->print(&printer);
         }
         delete dlg;
     #endif
     }

     void TextEdit::filePrintPreview()
     {
     #ifndef QT_NO_PRINTER
         QPrintPreviewDialog preview(this);
         connect(&preview, SIGNAL(paintRequested(QPrinter *)), SLOT(printPreview(QPrinter *)));
         preview.exec();
     #endif
     }

     void TextEdit::printPreview(QPrinter *printer)
     {
     #ifndef QT_NO_PRINTER
         textEdit->print(printer);
     #endif
     }

     void TextEdit::filePrintPdf()
     {
     #ifndef QT_NO_PRINTER
         QString fileName = QFileDialog::getSaveFileName(this, "Export PDF",
                                                         QString(), "*.pdf");
         if (!fileName.isEmpty()) {
             if (QFileInfo(fileName).suffix().isEmpty())
                 fileName.append(".pdf");
             QPrinter printer(QPrinter::HighResolution);
             printer.setOutputFormat(QPrinter::PdfFormat);
             printer.setOutputFileName(fileName);
             textEdit->document()->print(&printer);
         }
     #endif
     }

     void TextEdit::textBold()
     {
         QTextCharFormat fmt;
         fmt.setFontWeight(actionTextBold->isChecked() ? QFont::Bold : QFont::Normal);
         mergeFormatOnWordOrSelection(fmt);
     }

     void TextEdit::textUnderline()
     {
         QTextCharFormat fmt;
         fmt.setFontUnderline(actionTextUnderline->isChecked());
         mergeFormatOnWordOrSelection(fmt);
     }

     void TextEdit::textItalic()
     {
         QTextCharFormat fmt;
         fmt.setFontItalic(actionTextItalic->isChecked());
         mergeFormatOnWordOrSelection(fmt);
     }

     void TextEdit::textFamily(const QString &f)
     {
         QTextCharFormat fmt;
         fmt.setFontFamily(f);
         mergeFormatOnWordOrSelection(fmt);
     }

     void TextEdit::textSize(const QString &p)
     {
         QTextCharFormat fmt;
         fmt.setFontPointSize(p.toFloat());
         mergeFormatOnWordOrSelection(fmt);
     }

     void TextEdit::textStyle(int styleIndex)
     {
         QTextCursor cursor = textEdit->textCursor();

         if (styleIndex != 0) {
             QTextListFormat::Style style = QTextListFormat::ListDisc;

             switch (styleIndex) {
                 default:
                 case 1:
                     style = QTextListFormat::ListDisc;
                     break;
                 case 2:
                     style = QTextListFormat::ListCircle;
                     break;
                 case 3:
                     style = QTextListFormat::ListSquare;
                     break;
                 case 4:
                     style = QTextListFormat::ListDecimal;
                     break;
                 case 5:
                     style = QTextListFormat::ListLowerAlpha;
                     break;
                 case 6:
                     style = QTextListFormat::ListUpperAlpha;
                     break;
             }

             cursor.beginEditBlock();

             QTextBlockFormat blockFmt = cursor.blockFormat();

             QTextListFormat listFmt;

             if (cursor.currentList()) {
                 listFmt = cursor.currentList()->format();
             } else {
                 listFmt.setIndent(blockFmt.indent() + 1);
                 blockFmt.setIndent(0);
                 cursor.setBlockFormat(blockFmt);
             }

             listFmt.setStyle(style);

             cursor.createList(listFmt);

             cursor.endEditBlock();
         } else {
             // ####
             QTextBlockFormat bfmt;
             bfmt.setObjectIndex(-1);
             cursor.mergeBlockFormat(bfmt);
         }
     }

     void TextEdit::textColor()
     {
         QColor col = QColorDialog::getColor(textEdit->textColor(), this);
         if (!col.isValid())
             return;
         QTextCharFormat fmt;
         fmt.setForeground(col);
         mergeFormatOnWordOrSelection(fmt);
         colorChanged(col);
     }

     void TextEdit::textAlign(QAction *a)
     {
         if (a == actionAlignLeft)
             textEdit->setAlignment(Qt::AlignLeft);
         else if (a == actionAlignCenter)
             textEdit->setAlignment(Qt::AlignHCenter);
         else if (a == actionAlignRight)
             textEdit->setAlignment(Qt::AlignRight);
         else if (a == actionAlignJustify)
             textEdit->setAlignment(Qt::AlignJustify);
     }

     void TextEdit::currentCharFormatChanged(const QTextCharFormat &format)
     {
         fontChanged(format.font());
         colorChanged(format.foreground().color());
     }

     void TextEdit::cursorPositionChanged()
     {
         alignmentChanged(textEdit->alignment());
     }

     void TextEdit::clipboardDataChanged()
     {
         actionPaste->setEnabled(!QApplication::clipboard()->text().isEmpty());
     }

     void TextEdit::about()
     {
         QMessageBox::about(this, tr("About"), tr("This example demonstrates Qt's "
             "rich text editing facilities in action, providing an example "
             "document for you to experiment with."));
     }

     void TextEdit::mergeFormatOnWordOrSelection(const QTextCharFormat &format)
     {
         QTextCursor cursor = textEdit->textCursor();
         if (!cursor.hasSelection())
             cursor.select(QTextCursor::WordUnderCursor);
         cursor.mergeCharFormat(format);
         textEdit->mergeCurrentCharFormat(format);
     }

     void TextEdit::fontChanged(const QFont &f)
     {
         comboFont->setCurrentIndex(comboFont->findText(QFontInfo(f).family()));
         comboSize->setCurrentIndex(comboSize->findText(QString::number(f.pointSize())));
         actionTextBold->setChecked(f.bold());
         actionTextItalic->setChecked(f.italic());
         actionTextUnderline->setChecked(f.underline());
     }

     void TextEdit::colorChanged(const QColor &c)
     {
         QPixmap pix(16, 16);
         pix.fill(c);
         actionTextColor->setIcon(pix);
     }

     void TextEdit::alignmentChanged(Qt::Alignment a)
     {
         if (a & Qt::AlignLeft) {
             actionAlignLeft->setChecked(true);
         } else if (a & Qt::AlignHCenter) {
             actionAlignCenter->setChecked(true);
         } else if (a & Qt::AlignRight) {
             actionAlignRight->setChecked(true);
         } else if (a & Qt::AlignJustify) {
             actionAlignJustify->setChecked(true);
         }
     }