Qt：多文档（MDI）文档处理软件思路01
文档处理软件是我们日常生活中最为常用的软件之一。在此以将记事本为例子，实现的基本思路描述。
一：基本外观功能。
1）有菜单栏和按钮，根据不同的实现功能，将按钮添加到菜单中，并且添加工具栏。
2）主窗口显示（在此不同于记事本，为多文本窗口）。
在Qt中按钮的显示以QAction来替代，菜单和工具栏为QMenu和QToolBar，部分代码如下：
//in file menu. QAction* pActionNew; QAction* pActionOpen; QAction* pActionSave; QAction* pActionSaveAs; QAction* pActionExportPdf; QAction* pActionExit; QMenu* pMenuFile; QMenu* pMenuWindow;
因为主窗口是多文档显示，所以要在主窗口添加QMdiArea，以保存多文档。
QMdiArea* pMdiArea;
因为每个QAction实例都需对应一个相应的方法，故声明new、open、save、saveas、print、exit等file菜单需调用的方法。
以下为完整的mainwindow.h文件：
#ifndef MAINWINDOW_H
#define MAINWINDOW_H
#include <QMainWindow>
class QMdiArea;
class QAction;
class TextEditor;
class QMenu;
class QActionGroup;
class TextEditor;
class QCloseEvent;
class QDragEnterEvent;
namespace Ui {
class MainWindow;
}
class MainWindow : public QMainWindow
{
Q_OBJECT
public:
explicit MainWindow(QWidget *parent = 0);
~MainWindow();
protected:
virtual void closeEvent(QCloseEvent* cle);
private:
void setupFileMenuActions();
void setupMenusAndToolbar();
/**
@brief add TextEditor instance to MDIArea.
@param editor TextEditor instance.
*/
void addEditor(TextEditor* editor);
/**
@brief new a file in MDIArea.
*/
void newFile();
/**
@brief open a exist file.
*/
void openFile();
/**
@brief save file in defalut configuration.
*/
bool save();
/**
@brief save file by user option.
*/
bool saveAs();
/**
@brief export file in pdf format.
*/
void exportInPdfFormat();
/**
@brief find the active TextEditor and return it.
@return active TextEditor instance in MDIArea.
*/
TextEditor* activeEditor();
private:
Ui::MainWindow *ui;
//in file menu.
QAction* pActionNew;
QAction* pActionOpen;
QAction* pActionSave;
QAction* pActionSaveAs;
QAction* pActionExportPdf;
QAction* pActionExit;
QMenu* pMenuFile;
QMenu* pMenuWindow;
QMdiArea* pMdiArea;
QActionGroup* pWindowMenuGroup;
static QString mResWinPath;
};
#endif // MAINWINDOW_H
因为此程序为多窗口（Mdi）程序，所以针对程序中不同的文本框有不同的配置，例如文档保存情况，是否为active，不同的文件名及路径，所以将具体对文档的操作实现在文档类中（QTextEdit的子类），mainwindow只是对其的具体调用。
以下是mainwindow.cpp的具体实现：
#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <QMdiArea>
#include <QAction>
#include <QMenu>
#include <QMdiSubWindow>
#include <QActionGroup>
#include <QCloseEvent>
#include <QDragEnterEvent>
#include "texteditor.h"
QString MainWindow::mResWinPath = ":/images/win/";
MainWindow::MainWindow(QWidget *parent) :
QMainWindow(parent),
ui(new Ui::MainWindow),
pMdiArea(new QMdiArea(this)),
pWindowMenuGroup(new QActionGroup(this))
{
ui->setupUi(this);
setCentralWidget(pMdiArea);
setupFileMenuActions();
setupMenusAndToolbar();
setAttribute(Qt::WA_DeleteOnClose);
setAcceptDrops(true);
}
MainWindow::~MainWindow()
{
delete ui;
}
void MainWindow::closeEvent(QCloseEvent* cle)
{
pMdiArea->closeAllSubWindows();
if ( !pMdiArea->subWindowList().isEmpty()) {
cle->ignore();
} else {
cle->accept();
}
}
void MainWindow::setupFileMenuActions()
{
pActionNew = new QAction(QIcon(MainWindow::mResWinPath + "filenew.png"),
tr("&New"),
this);
pActionNew->setShortcut(QKeySequence::New);
pActionNew->setPriority(QAction::LowPriority);
pActionNew->setStatusTip(tr("Create a new file"));
connect(pActionNew, &QAction::triggered, this, &MainWindow::newFile);
pActionOpen = new QAction(QIcon(MainWindow::mResWinPath + "fileopen.png"),
tr("&Open"),
this);
pActionOpen->setShortcut(QKeySequence::Open);
pActionOpen->setPriority(QAction::LowPriority);
pActionOpen->setStatusTip(tr("Open a file"));
connect(pActionOpen, &QAction::triggered, this, &MainWindow::openFile);
pActionSave = new QAction(QIcon(MainWindow::mResWinPath + "filesave.png"),
tr("&Save"),
this);
pActionSave->setShortcut(QKeySequence::Save);
pActionSave->setStatusTip(tr("save this file"));
pActionSaveAs = new QAction(tr("Save As"), this);
pActionSaveAs->setShortcut(QKeySequence::SaveAs);
pActionSaveAs->setStatusTip(tr("Save this file as..."));
connect(pActionSaveAs, &QAction::triggered, this, &MainWindow::saveAs);
pActionExportPdf = new QAction(QIcon(MainWindow::mResWinPath + "exportpdf.png"),
tr("Export Pdf"),
this);
pActionExportPdf->setStatusTip(tr("export file in pdf format"));
connect(pActionExportPdf, &QAction::triggered, this, &MainWindow::exportInPdfFormat);
pActionExit = new QAction(tr("E&xit"), this);
pActionExit->setShortcut(QKeySequence::Quit);
pActionExit->setStatusTip(tr("Exit this application"));
connect(pActionExit, &QAction::triggered, qApp, &QApplication::closeAllWindows);
}
void MainWindow::setupMenusAndToolbar()
{
pMenuFile = ui->menuBar->addMenu(tr("&File"));
pMenuFile->addAction(pActionNew);
pMenuFile->addAction(pActionOpen);
pMenuFile->addAction(pActionSaveAs);
pMenuFile->addAction(pActionExportPdf);
pMenuFile->addAction(pActionExit);
QToolBar* tb = addToolBar(tr("FileToolBar"));
tb->addAction(pActionNew);
tb->addAction(pActionOpen);
tb->addAction(pActionSave);
tb->addAction(pActionExportPdf);
pMenuWindow = ui->menuBar->addMenu(tr("&Window"));
}
void MainWindow::addEditor(TextEditor* editor)
{
//Add action to windowMenuGroup for RadioGroup.
pMenuWindow->addAction(editor->windowMenuAction());
pWindowMenuGroup->addAction(editor->windowMenuAction());
QMdiSubWindow* subWindow = pMdiArea->addSubWindow(editor);
subWindow->show();
subWindow->setFocus();
}
void MainWindow::newFile()
{
//Create a new editor and add it to MDIArea.
TextEditor* editor(new TextEditor(this));
editor->newFile();
addEditor(editor);
}
void MainWindow::openFile()
{
//Call TextEditor::open method for user to choose file.
TextEditor* editor = TextEditor::open(this);
//true If choose file successfully,add the file to MDIArea.
if ( editor) {
addEditor(editor);
}
}
bool MainWindow::save()
{
TextEditor* editor = activeEditor();
if ( editor) {
return editor->save();
} else {
return false;
}
}
bool MainWindow::saveAs()
{
TextEditor* editor = activeEditor();
if ( editor) {
return editor->saveAs();
}
return false;
}
void MainWindow::exportInPdfFormat()
{
TextEditor* editor = activeEditor();
if ( editor) {
editor->fileExportToPDF();
}
}
TextEditor* MainWindow::activeEditor()
{
QMdiSubWindow* subWindow = pMdiArea->activeSubWindow();
if ( subWindow) {
return qobject_cast<TextEditor*>(subWindow->widget());
} else {
return 0;
}
}