文本编辑器

记事本类型的应用，可以打开、编辑、保存文本文档。可以增加单词高亮和其它的一些特性。

首先，对于这一个项目，可以说有点偷懒，因为如果要开始的毕竟是一个不小的项目，不使用浏览器的话，开发起来必然需要学习太多的东西，所以就使用了Qt中的一个小小的demo-----textedit，一个富文本的编辑器，之前曾经学习过Qt编程，但是真的没有好好了解过这一类的框架，这一次就当做是自己在学习这个小小的项目吧，如果之后再有什么想法再继续深入这个小项目~~

这个项目的最终结果是这样子的：

可以看出来，还是挺不错的嘛，嘿嘿，下面就来慢慢的解析它吧~

下面是这个项目的资源文件

mac：

win：

logo32.png：

看项目需要从最主要的配置文件开始看，下面首先了解一下这个小项目的配置文件：

textedit.pro:

TEMPLATE        = app
TARGET          = textedit
CONFIG          += qt warn_on
HEADERS         = textedit.h
SOURCES         = textedit.cpp \
                  main.cpp
RESOURCES += textedit.qrc
build_all:!build_pass {
    CONFIG -= build_all
    CONFIG += release
}
# install
target.path = $$[QT_INSTALL_DEMOS]/textedit
sources.files = $$SOURCES $$HEADERS $$RESOURCES *.pro *.html *.doc images
sources.path = $$[QT_INSTALL_DEMOS]/textedit
INSTALLS += target sources
symbian: include($$QT_SOURCE_TREE/demos/symbianpkgrules.pri)

TEMPLATE = app

A> app -建立一个应用程序的makefile。这是默认值，所以如果模板没有被指定，这个将被使用。
B> lib - 建立一个库的makefile。
C> vcapp - 建立一个应用程序的VisualStudio项目文件。
D> vclib - 建立一个库的VisualStudio项目文件。
E> subdirs -这是一个特殊的模板，它可以创建一个能够进入特定目录并且为一个项目文件生成makefile并且为它调用make的makefile。

“app”模板告诉qmake为建立一个应用程序生成一个makefile。当使用这个模板时，下面这些qmake系统变量是被承认的。你应该在你的.pro文件中使用它们来为你的应用程序指定特定信息。

TARGET = textedit

这一句表示了应用程序的名称

CONFIG += qt warn_on

CONFIG用来告诉qmake关于应用程序的配置信息。

CONFIG+= qt warn_on release

在这里使用“+=”，是因为我们添加我们的配置选项到任何一个已经存在中。这样做比使用“=”那样替换已经指定的所有选项是更安全的。
A> qt部分告诉qmake这个应用程序是使用Qt来连编的。这也就是说qmake在连接和为编译添加所需的包含路径的时候会考虑到Qt库的。
B> warn_on部分告诉qmake要把编译器设置为输出警告信息的。
C> release部分告诉qmake应用程序必须被连编为一个发布的应用程序。在开发过程中，程序员也可以使用debug来替换releas

HEADERS         = textedit.h
SOURCES         = textedit.cpp \
                  main.cpp

HEADERS - 应用程序中的所有头文件的列表。

SOURCES - 应用程序中的所有源文件的列表。

RESOURCES += textedit.qrc

加载了资源文件textedit.qrc，也就是上面的所有东西mac,win,logo32.png还有example.html

<!DOCTYPE RCC><RCC version="1.0">
<qresource prefix="/">
  <file>images/logo32.png</file>
  <file>images/mac/editcopy.png</file>
  <file>images/mac/editcut.png</file>
  <file>images/mac/editpaste.png</file>
  <file>images/mac/editredo.png</file>
  <file>images/mac/editundo.png</file>
  <file>images/mac/exportpdf.png</file>
  <file>images/mac/filenew.png</file>
  <file>images/mac/fileopen.png</file>
  <file>images/mac/fileprint.png</file>
  <file>images/mac/filesave.png</file>
  <file>images/mac/textbold.png</file>
  <file>images/mac/textcenter.png</file>
  <file>images/mac/textitalic.png</file>
  <file>images/mac/textjustify.png</file>
  <file>images/mac/textleft.png</file>
  <file>images/mac/textright.png</file>
  <file>images/mac/textunder.png</file>
  <file>images/mac/zoomin.png</file>
  <file>images/mac/zoomout.png</file>
  <file>images/win/editcopy.png</file>
  <file>images/win/editcut.png</file>
  <file>images/win/editpaste.png</file>
  <file>images/win/editredo.png</file>
  <file>images/win/editundo.png</file>
  <file>images/win/exportpdf.png</file>
  <file>images/win/filenew.png</file>
  <file>images/win/fileopen.png</file>
  <file>images/win/fileprint.png</file>
  <file>images/win/filesave.png</file>
  <file>images/win/textbold.png</file>
  <file>images/win/textcenter.png</file>
  <file>images/win/textitalic.png</file>
  <file>images/win/textjustify.png</file>
  <file>images/win/textleft.png</file>
  <file>images/win/textright.png</file>
  <file>images/win/textunder.png</file>
  <file>images/win/zoomin.png</file>
  <file>images/win/zoomout.png</file>
  <file>example.html</file>
</qresource>
</RCC>

FORMS - 应用程序中的所有.ui文件（由Qt设计器生成）的列表。
LEXSOURCES - 应用程序中的所有lex源文件的列表。
YACCSOURCES - 应用程序中的所有yacc源文件的列表。
TARGET - 可执行应用程序的名称。默认值为项目文件的名称。（如果需要扩展名，会被自动加上。）
DESTDIR - 放置可执行程序目标的目录。
DEFINES - 应用程序所需的额外的预处理程序定义的列表。
INCLUDEPATH - 应用程序所需的额外的包含路径的列表。
DEPENDPATH - 应用程序所依赖的搜索路径。
VPATH - 寻找补充文件的搜索路径。
DEF_FILE - 只有Windows需要：应用程序所要连接的.def文件。
RC_FILE - 只有Windows需要：应用程序的资源文件。
RES_FILE - 只有Windows需要：应用程序所要连接的资源文件。

你只需要使用那些你已经有值的系统变量，例如，如果你不需要任何额外的INCLUDEPATH，那么你就不需要指定它，qmake会为所需的提供默认值。例如，一个实例项目文件也许就像这样：

TEMPLATE = app
DESTDIR  = c:\helloapp
HEADERS += hello.h
SOURCES += hello.cpp 
SOURCES += main.cpp
DEFINES += QT_DLL
CONFIG  += qt warn_on release

如果条目是单值的，比如template或者目的目录，我们是用“=”，但如果是多值条目，我们使用“+=”来为这个类型添加现有的条目。使用“=”会用新值替换原有的值，例如，如果我们写了DEFINES=QT_DLL，其它所有的定义都将被删除。

target.path = $$[QT_INSTALL_DEMOS]/textedit

sources.files = $$SOURCES $$HEADERS $$RESOURCES *.pro *.html *.doc images

sources.path = $$[QT_INSTALL_DEMOS]/textedit

INSTALLS += target sources

目录文件路径，将所有的文件添加进来，包括所需要的资源文件，这样子我们就已经配置好了资源文件，下面我们需要做的就是如何利用这些资源文件建立我们的项目。首先这里还是列出来我们现在有的资源文件。

各种图片资源，主要是在image目录下面。我们需要的*.html文件，在目录文件下面。下面我们需要来观察一下我们的目录文件下面有的各种*.cpp文件。

main.cpp，textedit.cpp，textedit.h，textedit.qrc(资源文件)

main.cpp：

#include "textedit.h"
#include <QApplication>
int main( int argc, char ** argv )
{
    Q_INIT_RESOURCE(textedit);
    QApplication a( argc, argv );
    TextEdit mw;
    mw.resize( 700, 800 );
    mw.show();
    return a.exec();
}

首先还是包含了textedit.h文件，这个文件的主要功能是，继承了QMainWindow类，这样的话就可以生成窗口文件。初始化

Q_INIT_RESOURCE(textedit);

初始化资源文件（textedit.qrc）

下面的一句话是这样子解说的：

Initializes the window system and constructs an application object with argc command line arguments in argv.

初始化窗口系统和结构化一个有着 argc, argv参数的应用

生成一个textedit类。设置大小。show()函数

show():
显示一个非模式对话框。控制权即刻返回给调用函数。
弹出窗口是否模式对话框，取决于modal属性的值。

exec():
显示一个模式对话框，并且锁住程序直到用户关闭该对话框为止。函数返回一个DialogCode结果。
在对话框弹出期间，用户不可以切换同程序下的其它窗口，直到该对话框被关闭。

这样子说起来，application总是一个模式的对话框，因为一旦生成就锁定了，但是Windows窗口不是一个模式对话框，当它生成的时候直接的就返回了应该有的数值。所以在这个应用中出现这样的情况。

最后一句：return a.exec();

程序进入消息循环，等待可能输入进行响应。这里main()把控制权转交给Qt，Qt完成事件处理工作，当应用程序退出的时候exec()的值就会返回。在exec()中，Qt接受并处理用户和系统的事件并且把它们传递给适当的窗口部件。

最后来看一下，textedit文件，因为这里已经将应用程序的控制权转交给Qt的事件处理程序，这样子我们就需要搞清楚，Qt的事件循环队列现在究竟发生了什么事情。

在textedit.h文件中当然只有一个类，这个类继承了应该继承的Window窗口，并且还注册了许多事件处理机制。但是首先还是来看一下这个函数具体的行为是什么

#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

一开始的部分：

#ifndef TEXTEDIT_H

#define TEXTEDIT_H

如果没有包含textedit_h，就包含这个文件，总之就是不让这个文件重复定义。

#include <QMainWindow>
#include <QMap>
#include <QPointer>
这个部分包含了需要继承的QMainWindow类，还有QMap集合类，还有QPointer指针
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)

这写函数在网上查找说的是前置声明一样的东西，说的就像是头文件一样，但是问什么不直接的包含到头文件中去呢，这个还是后来再纠结吧。

下面需要我们对于这个类进行分析了，总算是到了重头戏了：

每一个窗口类中，对于Qt来说，只有在class中加入了Q_OBJECT，你才能使用QT中的signal和slot机制。

/****************************************************************************
**
** Copyright (C) 2013 Digia Plc and/or its subsidiary(-ies).
** Contact: http://www.qt-project.org/legal
**
** This file is part of the demonstration applications of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** Commercial License Usage
** Licensees holding valid commercial Qt licenses may use this file in
** accordance with the commercial license agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and Digia.  For licensing terms and
** conditions see http://qt.digia.com/licensing.  For further information
** use the contact form at http://qt.digia.com/contact-us.
**
** GNU Lesser General Public License Usage
** Alternatively, this file may be used under the terms of the GNU Lesser
** General Public License version 2.1 as published by the Free Software
** Foundation and appearing in the file LICENSE.LGPL included in the
** packaging of this file.  Please review the following information to
** ensure the GNU Lesser General Public License version 2.1 requirements
** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
**
** In addition, as a special exception, Digia gives you certain additional
** rights.  These rights are described in the Digia Qt LGPL Exception
** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
**
** GNU General Public License Usage
** Alternatively, this file may be used under the terms of the GNU
** General Public License version 3.0 as published by the Free Software
** Foundation and appearing in the file LICENSE.GPL included in the
** packaging of this file.  Please review the following information to
** ensure the GNU General Public License version 3.0 requirements will be
** met: http://www.gnu.org/copyleft/gpl.html.
**
**
** $QT_END_LICENSE$
**
****************************************************************************/
#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 <QTextDocumentWriter>
#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)
{
    setToolButtonStyle(Qt::ToolButtonFollowStyle);
    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(QTextCharFormat)),
            this, SLOT(currentCharFormatChanged(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)));
#ifndef QT_NO_CLIPBOARD
    connect(QApplication::clipboard(), SIGNAL(dataChanged()), this, SLOT(clipboardDataChanged()));
#endif
    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;
    QIcon newIcon = QIcon::fromTheme("document-new", QIcon(rsrcPath + "/filenew.png"));
    a = new QAction( newIcon, tr("&New"), this);
    a->setPriority(QAction::LowPriority);
    a->setShortcut(QKeySequence::New);
    connect(a, SIGNAL(triggered()), this, SLOT(fileNew()));
    tb->addAction(a);
    menu->addAction(a);
    a = new QAction(QIcon::fromTheme("document-open", 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::fromTheme("document-save", 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);
    a->setPriority(QAction::LowPriority);
    connect(a, SIGNAL(triggered()), this, SLOT(fileSaveAs()));
    menu->addAction(a);
    menu->addSeparator();
#ifndef QT_NO_PRINTER
    a = new QAction(QIcon::fromTheme("document-print", QIcon(rsrcPath + "/fileprint.png")),
                    tr("&Print..."), this);
    a->setPriority(QAction::LowPriority);
    a->setShortcut(QKeySequence::Print);
    connect(a, SIGNAL(triggered()), this, SLOT(filePrint()));
    tb->addAction(a);
    menu->addAction(a);
    a = new QAction(QIcon::fromTheme("fileprint", QIcon(rsrcPath + "/fileprint.png")),
                    tr("Print Preview..."), this);
    connect(a, SIGNAL(triggered()), this, SLOT(filePrintPreview()));
    menu->addAction(a);
    a = new QAction(QIcon::fromTheme("exportpdf", QIcon(rsrcPath + "/exportpdf.png")),
    tr("&Export PDF..."), this);
    a->setPriority(QAction::LowPriority);
    a->setShortcut(Qt::CTRL + Qt::Key_D);
    connect(a, SIGNAL(triggered()), this, SLOT(filePrintPdf()));
    tb->addAction(a);
    menu->addAction(a);
    menu->addSeparator();
#endif
    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::fromTheme("edit-undo", QIcon(rsrcPath + "/editundo.png")),
                                              tr("&Undo"), this);
    a->setShortcut(QKeySequence::Undo);
    tb->addAction(a);
    menu->addAction(a);
    a = actionRedo = new QAction(QIcon::fromTheme("edit-redo", QIcon(rsrcPath + "/editredo.png")),
                                              tr("&Redo"), this);
    a->setPriority(QAction::LowPriority);
    a->setShortcut(QKeySequence::Redo);
    tb->addAction(a);
    menu->addAction(a);
    menu->addSeparator();
    a = actionCut = new QAction(QIcon::fromTheme("edit-cut", QIcon(rsrcPath + "/editcut.png")),
                                             tr("Cu&t"), this);
    a->setPriority(QAction::LowPriority);
    a->setShortcut(QKeySequence::Cut);
    tb->addAction(a);
    menu->addAction(a);
    a = actionCopy = new QAction(QIcon::fromTheme("edit-copy", QIcon(rsrcPath + "/editcopy.png")),
                                 tr("&Copy"), this);
    a->setPriority(QAction::LowPriority);
    a->setShortcut(QKeySequence::Copy);
    tb->addAction(a);
    menu->addAction(a);
    a = actionPaste = new QAction(QIcon::fromTheme("edit-paste", QIcon(rsrcPath + "/editpaste.png")),
                                  tr("&Paste"), this);
    a->setPriority(QAction::LowPriority);
    a->setShortcut(QKeySequence::Paste);
    tb->addAction(a);
    menu->addAction(a);
#ifndef QT_NO_CLIPBOARD
    if (const QMimeData *md = QApplication::clipboard()->mimeData())
        actionPaste->setEnabled(md->hasText());
#endif
}
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::fromTheme("format-text-bold", QIcon(rsrcPath + "/textbold.png")),
                                 tr("&Bold"), this);
    actionTextBold->setShortcut(Qt::CTRL + Qt::Key_B);
    actionTextBold->setPriority(QAction::LowPriority);
    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::fromTheme("format-text-italic", QIcon(rsrcPath + "/textitalic.png")),
                                   tr("&Italic"), this);
    actionTextItalic->setPriority(QAction::LowPriority);
    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::fromTheme("format-text-underline", QIcon(rsrcPath + "/textunder.png")),
                                      tr("&Underline"), this);
    actionTextUnderline->setShortcut(Qt::CTRL + Qt::Key_U);
    actionTextUnderline->setPriority(QAction::LowPriority);
    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*)));
    // Make sure the alignLeft  is always left of the alignRight
    if (QApplication::isLeftToRight()) {
        actionAlignLeft = new QAction(QIcon::fromTheme("format-justify-left", QIcon(rsrcPath + "/textleft.png")),
                                      tr("&Left"), grp);
        actionAlignCenter = new QAction(QIcon::fromTheme("format-justify-center", QIcon(rsrcPath + "/textcenter.png")), tr("C&enter"), grp);
        actionAlignRight = new QAction(QIcon::fromTheme("format-justify-right", QIcon(rsrcPath + "/textright.png")), tr("&Right"), grp);
    } else {
        actionAlignRight = new QAction(QIcon::fromTheme("format-justify-right", QIcon(rsrcPath + "/textright.png")), tr("&Right"), grp);
        actionAlignCenter = new QAction(QIcon::fromTheme("format-justify-center", QIcon(rsrcPath + "/textcenter.png")), tr("C&enter"), grp);
        actionAlignLeft = new QAction(QIcon::fromTheme("format-justify-left", QIcon(rsrcPath + "/textleft.png")), tr("&Left"), grp);
    }
    actionAlignJustify = new QAction(QIcon::fromTheme("format-justify-fill", QIcon(rsrcPath + "/textjustify.png")), tr("&Justify"), grp);
    actionAlignLeft->setShortcut(Qt::CTRL + Qt::Key_L);
    actionAlignLeft->setCheckable(true);
    actionAlignLeft->setPriority(QAction::LowPriority);
    actionAlignCenter->setShortcut(Qt::CTRL + Qt::Key_E);
    actionAlignCenter->setCheckable(true);
    actionAlignCenter->setPriority(QAction::LowPriority);
    actionAlignRight->setShortcut(Qt::CTRL + Qt::Key_R);
    actionAlignRight->setCheckable(true);
    actionAlignRight->setPriority(QAction::LowPriority);
    actionAlignJustify->setShortcut(Qt::CTRL + Qt::Key_J);
    actionAlignJustify->setCheckable(true);
    actionAlignJustify->setPriority(QAction::LowPriority);
    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)");
    comboStyle->addItem("Ordered List (Roman lower)");
    comboStyle->addItem("Ordered List (Roman upper)");
    connect(comboStyle, SIGNAL(activated(int)),
            this, SLOT(textStyle(int)));
    comboFont = new QFontComboBox(tb);
    tb->addWidget(comboFont);
    connect(comboFont, SIGNAL(activated(QString)),
            this, SLOT(textFamily(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(QString)),
            this, SLOT(textSize(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();
    QTextDocumentWriter writer(fileName);
    bool success = writer.write(textEdit->document());
    if (success)
        textEdit->document()->setModified(false);
    return success;
}
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();
}
void TextEdit::filePrint()
{
#ifndef QT_NO_PRINTER
    QPrinter printer(QPrinter::HighResolution);
    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
    QPrinter printer(QPrinter::HighResolution);
    QPrintPreviewDialog preview(&printer, this);
    connect(&preview, SIGNAL(paintRequested(QPrinter*)), SLOT(printPreview(QPrinter*)));
    preview.exec();
#endif
}
void TextEdit::printPreview(QPrinter *printer)
{
#ifdef QT_NO_PRINTER
    Q_UNUSED(printer);
#else
    textEdit->print(printer);
#endif
}
void TextEdit::filePrintPdf()
{
#ifndef QT_NO_PRINTER
//! [0]
    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);
    }
//! [0]
#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)
{
    qreal pointSize = p.toFloat();
    if (p.toFloat() > 0) {
        QTextCharFormat fmt;
        fmt.setFontPointSize(pointSize);
        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;
            case 7:
                style = QTextListFormat::ListLowerRoman;
                break;
            case 8:
                style = QTextListFormat::ListUpperRoman;
                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 | 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);
}
void TextEdit::currentCharFormatChanged(const QTextCharFormat &format)
{
    fontChanged(format.font());
    colorChanged(format.foreground().color());
}
void TextEdit::cursorPositionChanged()
{
    alignmentChanged(textEdit->alignment());
}
void TextEdit::clipboardDataChanged()
{
#ifndef QT_NO_CLIPBOARD
    if (const QMimeData *md = QApplication::clipboard()->mimeData())
        actionPaste->setEnabled(md->hasText());
#endif
}
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);
    }
}

这个函数中最重要的部分还是初始化的部分：

TextEdit::TextEdit(QWidget *parent)
    : QMainWindow(parent)
{
    setToolButtonStyle(Qt::ToolButtonFollowStyle);
    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(QTextCharFormat)),
            this, SLOT(currentCharFormatChanged(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)));
#ifndef QT_NO_CLIPBOARD
    connect(QApplication::clipboard(), SIGNAL(dataChanged()), this, SLOT(clipboardDataChanged()));
#endif
    QString initialFile = ":/example.html";
    const QStringList args = QCoreApplication::arguments();
    if (args.count() == 2)
        initialFile = args.at(1);
    if (!load(initialFile))
        fileNew();
}

这里首先调用几个函数进行初始化，进行行为的连接，之后进行信号与槽机制的完善，对于每一个事件进行了各种有用的操作。最后生成了该文件。当然，这里的知识点在于，对于这些信号机制的深入了解现在现在的水平还不够，但是在初始化中进行各种行为的组成明显的可以的。这样，这个任务就算是基本结束了吧~~~

来自为知笔记(Wiz)

附件列表

posted @ 2015-12-14 11:31 pinwei1900 阅读(494) 评论(0) 收藏举报

刷新页面返回顶部

cliffff

文本编辑器

附件列表

公告