textedit源代码 -Qt学习笔记 -hxzon

http://hxzon00.blog.163.com/blog/static/104892416200996998768/

textedit源代码 -Qt学习笔记 -hxzon

头文件
======================================
#ifndef TEXTEDIT_H
#define TEXTEDIT_H
#include <QMainWindow>
#include <QMap>
#include <QPointer>
QT_FORWARD_DECLARE_CLASS(QAction)
QT_FORWARD_DECLARE_CLASS(QComboBox)
QT_FORWARD_DECLARE_CLASS(QFontComboBox)
QT_FORWARD_DECLARE_CLASS(QTextEdit)
QT_FORWARD_DECLARE_CLASS(QTextCharFormat)
QT_FORWARD_DECLARE_CLASS(QMenu)
class TextEdit : public QMainWindow
{
    Q_OBJECT
public:
    TextEdit(QWidget *parent = 0);
protected:
    virtual void closeEvent(QCloseEvent *e);
private:
    void setupFileActions();
    void setupEditActions();
    void setupTextActions();
    bool load(const QString &f);
    bool maybeSave();
    void setCurrentFileName(const QString &fileName);
private slots:
    void fileNew();
    void fileOpen();
    bool fileSave();
    bool fileSaveAs();
    void filePrint();
    void filePrintPreview();
    void filePrintPdf();
    void textBold();
    void textUnderline();
    void textItalic();
    void textFamily(const QString &f);
    void textSize(const QString &p);
    void textStyle(int styleIndex);
    void textColor();
    void textAlign(QAction *a);
    void currentCharFormatChanged(const QTextCharFormat &format);
    void cursorPositionChanged();
    void clipboardDataChanged();
    void about();
    void printPreview(QPrinter *);
private:
    void mergeFormatOnWordOrSelection(const QTextCharFormat &format);
    void fontChanged(const QFont &f);
    void colorChanged(const QColor &c);
    void alignmentChanged(Qt::Alignment a);
    QAction *actionSave,
        *actionTextBold,
        *actionTextUnderline,
        *actionTextItalic,
        *actionTextColor,
        *actionAlignLeft,
        *actionAlignCenter,
        *actionAlignRight,
        *actionAlignJustify,
        *actionUndo,
        *actionRedo,
        *actionCut,
        *actionCopy,
        *actionPaste;
    QComboBox *comboStyle;
    QFontComboBox *comboFont;
    QComboBox *comboSize;
    QToolBar *tb;
    QString fileName;
    QTextEdit *textEdit;
};
#endif
=============================================
初始化界面，添加各种事件
--------------------
将textEdit的字体样式改变和光标位置改变信号转发给本实例。
    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();
    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();
---------------------------
    QToolBar *tb = new QToolBar(this);//按钮条，本例不止一个按钮条
    tb->setWindowTitle(tr("File Actions"));
    addToolBar(tb);//窗体添加按钮条
    QMenu *menu = new QMenu(tr("&File"), this);//file菜单
    menuBar()->addMenu(menu);//菜单栏添加file菜单
    QAction *a;
    a = new QAction(QIcon(rsrcPath + "/filenew.png"), tr("&New"), this);//定义一个动作
    a->setShortcut(QKeySequence::New);//快捷键
    connect(a, SIGNAL(triggered()), this, SLOT(fileNew()));//监听，通过信号和槽链接//发射信号 emit triggered();
    tb->addAction(a);//按钮条添加按钮项
    menu->addAction(a);//file菜单添加菜单项
    a = new QAction(QIcon(rsrcPath + "/fileopen.png"), tr("&Open..."), this);
    a->setShortcut(QKeySequence::Open);
    connect(a, SIGNAL(triggered()), this, SLOT(fileOpen()));//此菜单触发打开文件操作
    tb->addAction(a);
    menu->addAction(a);
    menu->addSeparator();//file菜单添加分割线
----------------------------
actionPaste->setEnabled(!QApplication::clipboard()->text().isEmpty());
----------------------------
    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);//
---------------------------------
对齐操作
    QActionGroup *grp = new QActionGroup(this);
    connect(grp, SIGNAL(triggered(QAction *)), this, SLOT(textAlign(QAction *)));
    // Make sure the alignLeft is always left of the alignRight
    if (QApplication::isLeftToRight()) {
        actionAlignLeft = new QAction(QIcon(rsrcPath + "/textleft.png"), tr("&Left"), grp);
        actionAlignCenter = new QAction(QIcon(rsrcPath + "/textcenter.png"), tr("C&enter"), grp);
        actionAlignRight = new QAction(QIcon(rsrcPath + "/textright.png"), tr("&Right"), grp);
    } else {
        actionAlignRight = new QAction(QIcon(rsrcPath + "/textright.png"), tr("&Right"), grp);
        actionAlignCenter = new QAction(QIcon(rsrcPath + "/textcenter.png"), tr("C&enter"), grp);
        actionAlignLeft = new QAction(QIcon(rsrcPath + "/textleft.png"), tr("&Left"), grp);
    }
    actionAlignJustify = new QAction(QIcon(rsrcPath + "/textjustify.png"), tr("&Justify"), grp);
    actionAlignLeft->setShortcut(Qt::CTRL + Qt::Key_L);
    actionAlignLeft->setCheckable(true);
    actionAlignCenter->setShortcut(Qt::CTRL + Qt::Key_E);
    actionAlignCenter->setCheckable(true);
    actionAlignRight->setShortcut(Qt::CTRL + Qt::Key_R);
    actionAlignRight->setCheckable(true);
    actionAlignJustify->setShortcut(Qt::CTRL + Qt::Key_J);
    actionAlignJustify->setCheckable(true);
    tb->addActions(grp->actions());
    menu->addActions(grp->actions());
------------------------------------
//并列项样式
    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)));
//字体样式
    comboFont = new QFontComboBox(tb);
    tb->addWidget(comboFont);
    connect(comboFont, SIGNAL(activated(const QString &)),
            this, SLOT(textFamily(const QString &)));
//字体大小
    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())));
-----------------------------
-----------------------------
事件响应操作：
关闭操作
void TextEdit::closeEvent(QCloseEvent *e)
{
    if (maybeSave())
        e->accept();
    else
        e->ignore();
}
加载文件
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;
}
--------------------------
是否保存
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;
}
----------------
新建文件
void TextEdit::fileNew()
{
    if (maybeSave()) {
        textEdit->clear();
        setCurrentFileName(QString());
    }
}
打开文件，打开选择对话框
void TextEdit::fileOpen()
{
    QString fn = QFileDialog::getOpenFileName(this, tr("Open File..."),
                                              QString(), tr("HTML-Files (*.htm *.html);;All Files (*)"));
    if (!fn.isEmpty())
        load(fn);
}
保存文件
bool TextEdit::fileSave()
{
    if (fileName.isEmpty())
        return fileSaveAs();
    QTextDocumentWriter writer(fileName);
    bool success = writer.write(textEdit->document());
    if (success)
        textEdit->document()->setModified(false);
    return success;
}
另存为，保存路径对话框
bool TextEdit::fileSaveAs()
{
    QString fn = QFileDialog::getSaveFileName(this, tr("Save as..."),
                                              QString(), tr("ODF files (*.odt);;HTML-Files (*.htm *.html);;All Files (*)"));
    if (fn.isEmpty())
        return false;
    if (! (fn.endsWith(".odt", Qt::CaseInsensitive) || fn.endsWith(".htm", Qt::CaseInsensitive) || fn.endsWith(".html", Qt::CaseInsensitive)) )
        fn += ".odt"; // default
    setCurrentFileName(fn);
    return fileSave();
}
-------------------
设置字体粗细
void TextEdit::textBold()
{
    QTextCharFormat fmt;
    fmt.setFontWeight(actionTextBold->isChecked() ? QFont::Bold : QFont::Normal);
    mergeFormatOnWordOrSelection(fmt);
}
设置并列项样式
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);
    }
}
设置颜色，打开颜色选择对话框
void TextEdit::textColor()
{
    QColor col = QColorDialog::getColor(textEdit->textColor(), this);
    if (!col.isValid())
        return;
    QTextCharFormat fmt;
    fmt.setForeground(col);
    mergeFormatOnWordOrSelection(fmt);
    colorChanged(col);
}
设置对齐样式，以组为单位
void TextEdit::textAlign(QAction *a)
{
    if (a == actionAlignLeft)
        textEdit->setAlignment(Qt::AlignLeft | Qt::AlignAbsolute);
    else if (a == actionAlignCenter)
        textEdit->setAlignment(Qt::AlignHCenter);
    else if (a == actionAlignRight)
        textEdit->setAlignment(Qt::AlignRight | Qt::AlignAbsolute);
    else if (a == actionAlignJustify)
        textEdit->setAlignment(Qt::AlignJustify);
}
--------------------
字体样式改变
void TextEdit::currentCharFormatChanged(const QTextCharFormat &format)
{
    fontChanged(format.font());
    colorChanged(format.foreground().color());
}
光标位置改变
void TextEdit::cursorPositionChanged()
{
    alignmentChanged(textEdit->alignment());
}
剪贴板改变
void TextEdit::clipboardDataChanged()
{
    actionPaste->setEnabled(!QApplication::clipboard()->text().isEmpty());
}
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);
}
对齐样式改变
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);
    }
}
------------------------
改变样式，合并样式
void TextEdit::mergeFormatOnWordOrSelection(const QTextCharFormat &format)
{
    QTextCursor cursor = textEdit->textCursor();
    if (!cursor.hasSelection())
        cursor.select(QTextCursor::WordUnderCursor);
    cursor.mergeCharFormat(format);
    textEdit->mergeCurrentCharFormat(format);
}