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本文目錄一覽：

1、pos機業務開發

pos機業務開發

一、界面開發

NotePad使用主窗口作為頂層窗口組件，使用QMainWindow作為基類，QMainWindow內部封裝了菜單欄、工具欄、中央組件、?？拷M件、狀態欄等。QMainWindow內置了布局管理器，基本的組件布局如下：

使用二階構造模式構建NotePad界面。

MainWindow::MainWindow(){resize(800, 600);}MainWindow::~MainWindow(){}MainWindow* MainWindow::newInstance(){MainWindow* ret = new MainWindow();if((ret == NULL) || (!ret->construct())){delete ret;ret = NULL;}return ret;}bool MainWindow::construct(){bool ret = true;ret = ret && initMenuBar();//菜單欄構建ret = ret && initToolBar();//工具欄構建ret = ret && initStatusBar();//狀態欄構建ret = ret && initMainEditor();//中央組件構建return ret;}

1、菜單欄

QT中提供了預定義的與菜單相關的類組件，菜單欄QMenuBar，下拉菜單QMenu，菜單項QAction。

    QMenuBar* mb = menuBar();    QMenu* menu = new QMenu("File(&F)");    QAction *action = new QAction(text, NULL);    menu->addAction(action);    mb->addMenu(menu);

快捷鍵設置

action->setShortcut(QKeySequence(KEY));

QKeySequence是QT中與快捷鍵相關的類，KEY是QT中代表鍵值的常量。

NotePad菜單欄共有文件、編輯、格式、查看、幫助五組下拉菜單，每組下拉菜單使用一個函數構建。

bool MainWindow::initMenuBar(){bool ret = true;QMenuBar *mb = menuBar();ret = ret && initFileMenu(mb);ret = ret && initEditMenu(mb);ret = ret && initFormatMenu(mb);ret = ret && initViewMenu(mb);ret = ret && initHelpMenu(mb);return ret;}bool MainWindow::initFileMenu(QMenuBar *mb){QMenu *menu = new QMenu("File(&F)");bool ret = (menu != NULL);if(ret){QAction *action = NULL;ret = ret && makeAction(action, "New(&N)", Qt::CTRL + Qt::Key_N);if(ret){menu->addAction(action);}ret = ret && makeAction(action, "Open(&O)", Qt::CTRL + Qt::Key_O);if(ret){menu->addAction(action);}ret = ret && makeAction(action, "Save(&S)", Qt::CTRL + Qt::Key_S);if(ret){menu->addAction(action);}ret = ret && makeAction(action, "Save As(&A)", 0);if(ret){menu->addAction(action);}menu->addSeparator();ret = ret && makeAction(action, "Page Setting(&U)", 0);if(ret){menu->addAction(action);}ret = ret && makeAction(action, "Print(&P)", Qt::CTRL + Qt::Key_P);if(ret){menu->addAction(action);}menu->addSeparator();ret = ret && makeAction(action, "Exit(&X)", 0);if(ret){menu->addAction(action);}}if(ret){mb->addMenu(menu);}else{delete menu;}return ret;}bool MainWindow::makeAction(QAction *&action, QString text, int key){bool ret = true;action = new QAction(text, NULL);if(action != NULL){action->setShortcut(QKeySequence(key));}else{ret = false;}return ret;}bool MainWindow::initEditMenu(QMenuBar *mb){QMenu *menu = new QMenu("Edit(&E)", NULL);bool ret = (menu != NULL);if(ret){QAction *action = NULL;ret = ret && makeAction(action, "Undo(&U)", Qt::CTRL + Qt::Key_Z);if(ret){menu->addAction(action);}menu->addSeparator();ret = ret && makeAction(action, "Cut(&T)", Qt::CTRL + Qt::Key_X);if(ret){menu->addAction(action);}ret = ret && makeAction(action, "copy(&C)", Qt::CTRL + Qt::Key_C);if(ret){menu->addAction(action);}ret = ret && makeAction(action, "Paste(&P)", Qt::CTRL + Qt::Key_V);if(ret){menu->addAction(action);}ret = ret && makeAction(action, "Delete(&L)", Qt::Key_Delete);if(ret){menu->addAction(action);}menu->addSeparator();ret = ret && makeAction(action, "Find(&F)", Qt::CTRL + Qt::Key_F);if(ret){menu->addAction(action);}ret = ret && makeAction(action, "Find Next(&N)", Qt::Key_F3);if(ret){menu->addAction(action);}ret = ret && makeAction(action, "Replace(&R)", Qt::CTRL + Qt::Key_H);if(ret){menu->addAction(action);}ret = ret && makeAction(action, "Goto(&G)", Qt::CTRL + Qt::Key_G);if(ret){menu->addAction(action);}menu->addSeparator();ret = ret && makeAction(action, "All(&A)", Qt::CTRL + Qt::Key_A);if(ret){menu->addAction(action);}ret = ret && makeAction(action, "Time/Date(&D)", Qt::Key_F5);if(ret){menu->addAction(action);}}if(ret){mb->addMenu(menu);}else{delete menu;}return ret;}bool MainWindow::initFormatMenu(QMenuBar *mb){QMenu *menu = new QMenu("Format(&O)", NULL);bool ret = (menu != NULL);if(ret){QAction *action = NULL;ret = ret && makeAction(action, "Auto Wrap(&W)", 0);if(ret){menu->addAction(action);}menu->addSeparator();ret = ret && makeAction(action, "Font(&F)", 0);if(ret){menu->addAction(action);}}if(ret){mb->addMenu(menu);}else{delete menu;}return ret;}bool MainWindow::initViewMenu(QMenuBar *mb){QMenu *menu = new QMenu("View(&V)", NULL);bool ret = (menu != NULL);if(ret){QAction *action = NULL;ret = ret && makeAction(action, "Status(&S)", 0);if(ret){menu->addAction(action);}}if(ret){mb->addMenu(menu);}else{delete menu;}return ret;}bool MainWindow::initHelpMenu(QMenuBar *mb){QMenu *menu = new QMenu("Help(&H)", NULL);bool ret = (menu != NULL);if(ret){QAction *action = NULL;ret = ret && makeAction(action, "Help(&H)", 0);if(ret){menu->addAction(action);}menu->addSeparator();ret = ret && makeAction(action, "About NotePad(&A)", 0);if(ret){menu->addAction(action);}}if(ret){mb->addMenu(menu);}else{delete menu;}return ret;}

2、工具欄

工具欄是應用程序中集成各種功能使用快捷方式的區域，不是應用程序必須存在的組件，工具欄的元素可以是各種窗口組件，但通常以圖標按鈕的方式存在。

QT中提供了預定義的工具欄相關組件，工具欄QToolBar和快捷項QAction。

    //創建工具欄    QToolBar *tb = addToolBar("ToolBar");        //創建工具欄選項        QAction *action = new QAction("", NULL);    action->setToolTip(“Open”);    action->setIcon(QIcon(“/res/pic/open.png”));        //將工具欄選項加入工具欄    tb->addAction(action);    void setFloatable(bool floatable)設置工具欄為浮動    void setMovable(bool movable)設置工具欄為可移動    void setIconSize(const QSize & iconSize)設置工具欄的圖標大小    QTollBar組件中可以加入QT中的任意QWidget組件。    將菜單欄中的主要常用功能添加到工具欄中，按照功能所屬的菜單欄進行分組創建。bool MainWindow::initToolBar(){bool ret = true;QToolBar *tb = addToolBar("ToolBar");tb->setMovable(false);tb->setIconSize(QSize(16, 16));ret = ret && initFileToolItem(tb);//創建文件菜單欄的功能到工具欄ret = ret && initEditToolItem(tb);//創建編輯菜單欄到工具欄ret = ret && initFormatToolItem(tb);//創建格式菜單欄到工具欄ret = ret && initViewToolItem(tb);//創建查看菜單欄到工具欄return ret;}bool MainWindow::initFileToolItem(QToolBar *tb){bool ret = true;QAction *action = NULL;ret = ret && makeAction(action, "New", ":/res/pic/new.png");if( ret ){tb->addAction(action);}ret = ret && makeAction(action, "Open", ":/res/pic/open.png");if( ret ){tb->addAction(action);}ret = ret && makeAction(action, "Save", ":/res/pic/save.png");if( ret ){tb->addAction(action);}ret = ret && makeAction(action, "SaveAs", ":/res/pic/saveas.png");if( ret ){tb->addAction(action);}ret = ret && makeAction(action, "Print", ":/res/pic/print.png");if( ret ){tb->addAction(action);}tb->addSeparator();return ret;}bool MainWindow::initEditToolItem(QToolBar* tb){bool ret = true;QAction *action = NULL;ret = ret && makeAction(action, "Undo", ":/res/pic/undo.png");if( ret ){tb->addAction(action);}ret = ret && makeAction(action, "Redo", ":/res/pic/redo.png");if( ret ){tb->addAction(action);}ret = ret && makeAction(action, "Cut", ":/res/pic/cut.png");if( ret ){tb->addAction(action);}ret = ret && makeAction(action, "Copy", ":/res/pic/copy.png");if( ret ){tb->addAction(action);}ret = ret && makeAction(action, "Paste", ":/res/pic/paste.png");if( ret ){tb->addAction(action);}ret = ret && makeAction(action, "Find", ":/res/pic/find.png");if( ret ){tb->addAction(action);}ret = ret && makeAction(action, "Replace", ":/res/pic/replace.png");if( ret ){tb->addAction(action);}ret = ret && makeAction(action, "Goto", ":/res/pic/goto.png");if( ret ){tb->addAction(action);}tb->addSeparator();return ret;}bool MainWindow::initFormatToolItem(QToolBar* tb){bool ret = true;QAction *action = NULL;ret = ret && makeAction(action, "Auto Wrap", ":/res/pic/wrap.png");if( ret ){tb->addAction(action);}ret = ret && makeAction(action, "Font", ":/res/pic/font.png");if( ret ){tb->addAction(action);}tb->addSeparator();return ret;}bool MainWindow::initViewToolItem(QToolBar* tb){bool ret = true;QAction *action = NULL;ret = ret && makeAction(action, "ToolBar", ":/res/pic/tool.png");if( ret ){tb->addAction(action);}ret = ret && makeAction(action, "Status", ":/res/pic/status.png");if( ret ){tb->addAction(action);}return ret;}bool MainWindow::makeAction(QAction*& action, QString tip, QString icon){bool ret = true;action = new QAction("", NULL);if( action != NULL ){action->setToolTip(tip);action->setIcon(QIcon(icon));}else{ret = false;}return ret;}

3、狀態欄

狀態欄是應用程序中輸出簡要信息的區域，一般位于窗口的底部。狀態欄顯示的消息類型如下：

A、實時消息，如當前程序狀態

B、永久消息，如程序版本，開發機構

C、進度消息，進度顯示

QT中提供了預定義的狀態欄相關組件狀態欄QStatusBar，QStatusBar是容器型組件，可以是任意組件QWidget的父組件。

QT狀態欄的一般設計原則：

A、狀態欄左邊區域用于輸出實時消息

B、狀態欄右邊區域用于輸出永久消息

因此，addWidget函數用于在狀態欄左邊區域添加組件，addPermanentWidget函數用于在狀態欄右邊區域添加組件。

bool MainWindow::initStatusBar(){bool ret = true;QStatusBar *sb = statusBar();QLabel *label = new QLabel("CopyRight @Scorpio Studio");if(label != NULL){label->setMinimumwidth="360px",height="auto" />

4、中央組件

中央組件是多行文本編組件，使用QPlainTextEdit組件。

bool MainWindow::initMainEditor(){bool ret = true;//設置mainEditor的父組件mainEditor.setParent(this);//設置中央組件為mainEditorsetCentralWidget(&mainEditor);//設置mainEditor的背景色為豆沙綠QPalette p = mainEditor.palette();p.setColor(QPalette::Base, QColor(204, 232, 207));mainEditor.setPalette(p);return ret;}

二、核心功能開發

1、信號與槽函數

考慮到用戶界面與業務邏輯代碼的分離，槽函數實現需要與界面實現向分離，槽函數在新建MainwWindowSlots.cpp文件中實現,界面文件名稱改為MainWindowUI.cpp。

菜單欄與工具欄中的QAction對象在鼠標點擊后會發送triggered()信號，通過信號與槽機制可以實現對QAction對象的操作的處理。

connect(action, SIGNAL(triggered()), this, SLOT(slotfunction));

在QAction對象創建的時候連接信號與槽函數。

2、文件的存取操作

創建文件對話框：

QString MainWindow::createFileDialog(QFileDialog::AcceptMode mode, QString title){QString ret = "";QFileDialog filedialog(this);QStringList filter;filter.append("Text Files (*.txt)");filter.append("All Files (*.*)");filedialog.setWindowTitle(title);filedialog.setAcceptMode(mode);filedialog.setNameFilters(filter);if(mode == QFileDialog::AcceptOpen){filedialog.setFileMode(QFileDialog::ExistingFile);}if(filedialog.exec() == QFileDialog::Accepted){ret = filedialog.selectedFiles()[0];}return ret;}

錯誤消息提示框：

void MainWindow::showErrorMessage(const QString& title, const QString & text, QMessageBox::StandardButtons buttons){QMessageBox::critical(this, title, text, buttons);}

打開文件：

void MainWindow::onFileOpen(){QString path = createFileDialog(QFileDialog::AcceptOpen, "Open");if(path != ""){QFile file(path);if(file.open(QIODevice::ReadOnly | QIODevice::Text)){mainEditor.setPlainText(QString(file.readAll()));file.close();m_filepath = path;setWindowTitle("NotePad - [" + m_filepath + "]");}else{showErrorMessage(QString("Error"), QString("Open file error: " + m_filepath), QMessageBox::Ok);}}}

保存文件：

void MainWindow::onFileSave(){if(m_filepath == ""){m_filepath = createFileDialog(QFileDialog::AcceptSave, "Save");}if(m_filepath != ""){QFile file(m_filepath);if(file.open(QIODevice::WriteOnly | QIODevice::Text)){QTextStream out(&file);out << mainEditor.toPlainText();file.close();setWindowTitle("NotePad - [ " + m_filepath + " ]");}else{showErrorMessage(QString("Error"), QString("Save file error: " + m_filepath), QMessageBox::Ok);m_filepath = "";}}}

另存文件：

void MainWindow::onFileSaveAs(){QString path = createFileDialog(QFileDialog::AcceptSave, "Save As");if(path != ""){QFile file(path);if(file.open(QIODevice::WriteOnly | QIODevice::Text)){QTextStream out(&file);out << mainEditor.toPlainText();file.close();m_filepath = path;setWindowTitle("NotePad - [ " + m_filepath + " ]");}else{showErrorMessage(QString("Error"), QString("Save as error: " + m_filepath), QMessageBox::Ok);}}}

創建新文件：

void MainWindow::onFileNew(){preTextChanged();if(!m_isTextChanged){mainEditor.clear();setWindowTitle("NotePad - [New ]");m_filepath = "";m_isTextChanged = false;}}

3、編輯區的數據交互

    QPlainTextEdit編輯器組件提供了編輯交互功能接口。    QPlainTextEdit內置的信號如下：    void textChanged()    void copyAvailable(bool yes)    void redoAvailable(bool available)    void undoAvailable(bool available)    void cursorPositionChanged()        void modificationChanged(bool changed)    QPlainTextEdit內置的槽函數如下：    void copy()    void cut()    void paste()    void redo()    void selectAll()    void undo()

將菜單欄、工具欄中的copy、cut、paste、redo、undo等編輯操作QAction對象的triggered()信號連接到QPlainTextEdit對象的相應操作的槽函數，即可實現編輯操作。

    connect(action, SIGNAL(triggered(bool)), &mainEditor, SLOT(undo());    connect(action, SIGNAL(triggered()), &mainEditor, SLOT(cut()));    connect(action, SIGNAL(triggered()), &mainEditor, SLOT(copy()));    connect(action, SIGNAL(triggered()), &mainEditor, SLOT(paste());

工具欄QAction對象的界面狀態的設置

在創建Copy、Undo、Redo的QAction對象時設置為不可用狀態。

將QPlainTextEdit對象的copyAvailable、undoAvailable、redoAvailable信號連接到自定義槽函數。

   connect(&mainEditor, SIGNAL(copyAvailable(bool)), this, SLOT(onCopyAvailable(bool)));   connect(&mainEditor, SIGNAL(undoAvailable(bool)), this, SLOT(onUndoAvailable(bool)));   connect(&mainEditor, SIGNAL(redoAvailable(bool)), this, SLOT(onRedoAvailable(bool)));

在自定義槽函數中根據信號的參數available設置QAction對象的狀態

void MainWindow::onCopyAvailable(bool available){findMenuBarItem("Copy")->setEnabled(available);findMenuBarItem("Cut")->setEnabled(available);findToolBarItem("Copy")->setEnabled(available);findToolBarItem("Cut")->setEnabled(available);}void MainWindow::onUndoAvailable(bool available){findMenuBarItem("Undo")->setEnabled(available);findToolBarItem("Undo")->setEnabled(available);}void MainWindow::onRedoAvailable(bool available){findToolBarItem("Redo")->setEnabled(available);}

4、拖放支持

拖放一個文件進入窗口時將觸發拖放事件，QWidget對象都能處理拖放事件。

設置窗口支持拖放事件：

在構造函數調用setAcceptDrops(true);

重寫拖放事件的處理函數：

void dragEnterEvent(QDragEnterEvent *event);

void dropEvent(QDropEvent *event);

默認情況下，QPlainTextEdit接受來自其他應用程序拖拽來的文本，把文件名顯示出來。由于DropEvent是由子組件向父組件傳播的，通過禁止QPlainTextEdit的DropEvent，主窗口可以獲取DropEvent，MainWindow中就可以處理DropEvent。

在MainWwindow構造函數中需要禁止QPlainTextEdit接受DropEvent，允許MainWindow接受DropEvent。

mainEditor.setAcceptDrops(false);

setAcceptDrops(true);

重寫事件處理函數：

void MainWindow::dragEnterEvent(QDragEnterEvent *event){if(event->mimeData()->hasFormat("text/uri-list")){event->acceptProposedAction();}else{event->ignore();}}void MainWindow::dropEvent(QDropEvent *event){if(event->mimeData()->hasUrls()){QList<QUrl> list = event->mimeData()->urls();QString path = list[0].toLocalFile();QFileInfo fi(path);if( fi.isFile() ){preTextChanged();if(!m_isTextChanged){loadFile(path);}}else{showMessage(this, QMessageBox::Critical, "Error", "Open file error", QMessageBox::Ok);}}else{event->ignore();}}

5、打印支持

QTextDocument是表示文本及文本屬性的數據類。可以設置文本屬性如：排版、字體、標題；獲取文本參數如：行數、文本寬度、文本信息；實現標準操作如：撤銷、重做、查找、打印。

打印功能實現如下：

A、連接打印功能的QAction對象到打印功能槽函數

B、在打印槽函數中定義打印對話框

C、根據用戶選擇獲取QPrinter對象

D、使用QTextDocument對象進行打印

void MainWindow::onPrint(){QPrintDialog printdialog(this);printdialog.setWindowTitle("Print");if(printdialog.exec() == QPrintDialog::Accepted){QPrinter *printer = printdialog.printer();mainEditor.document()->print(printer);}}

6、光標定位

QPlainTextEdit編輯框內部包含QTextCursor對象。

    [signal] void QPlainTextEdit::cursorPositionChanged()    QTextCursor QPlainTextEdit::textCursor() const    int QTextCursor::position() const void MainWindow::onCursorChanged(){int pos = mainEditor.textCursor().position();QString text = mainEditor.toPlainText();int colum = 0;int row = 0;int flag = -1;for(int i = 0; i < pos; i++){if( text[i] == '\' ){row++;flag = i;}}flag++;colum = pos - flag;m_status.setText("Line: " + QString::number(row + 1) + " Colum: " + QString::number(colum + 1));}

7、查找功能

1）查找對話框的功能：

A、可復用的組件

B、查找文本框中的指定字符串

C、能夠指定查找方向

D、支持大小寫敏感查找

（2）查找對話框架構設計如下：

（3）查找對話框的界面布局：

4）查找功能的實現：

A、獲取當前光標的位置作為起始點

B、查找目標第一次出現的位置

C、通過目標位置和目標長度在文本框內進行標記

QString類提供了字符串中查找子串的函數：

int QString::indexOf(const QString &str, int from = 0, Qt::CaseSensitivity cs = Qt::CaseSensitive) const

從指定位置向后查找子串的下標位置

int QString::lastIndexOf(const QString &str, int from = -1, Qt::CaseSensitivity cs = Qt::CaseSensitive) const

從指定位置向前查找子串的下標位置

QPlainTextEdit文本框中選中子串的標記

QTextCursor cursor = m_textedit->textCursor();//獲取當前光標

cursor.setPosition(index);//設置光標到下標index

cursor.setPosition(index + target.length(), QTextCursor::KeepAnchor);//設置文本選擇范圍

m_textedit->setTextCursor(cursor);//設置光標信息到文本

（5）FindDailog類與MainWindow類的弱耦合關系

通過setPlainTextEdit(pText)設置FindDailog查找對話框指向的文本框，確立了FindDailog類與MainWindow類的弱耦合關系。

8、調色板設置

 //設置mainEditor的背景色為豆沙綠    QPalette p = mainEditor.palette();    p.setColor(QPalette::Base, QColor(204, 232, 207));    p.setColor(QPalette::Inactive, QPalette::Highlight, p.color(QPalette::Active, QPalette::Highlight));    p.setColor(QPalette::Inactive, QPalette::HighlightedText, p.color(QPalette::Active, QPalette::HighlightedText));    mainEditor.setPalette(p);

9、替換功能

替換對話框的功能：

A、可復用的組件

B、查找文本框中的字符串

C、替換當前查找到的字符串

D、替換所有的字符串

E、點擊關閉按鈕后隱藏

替換對話框的架構設計：

考慮到FindDialog類代碼復用，RepalceDialog類繼承自FindDialog。

替換對話框界面設計：

m_replacelabel.setText("Replace To:");m_replacebutton.setText("Replace");m_replaceallbutton.setText("Replace All");m_layout.removeWidget(&m_check);m_layout.removeWidget(&m_radiogroup);m_layout.removeWidget(&m_cancelbutton);m_layout.addWidget(&m_replacelabel, 1, 0);m_layout.addWidget(&m_replaceedit, 1, 1);m_layout.addWidget(&m_replacebutton, 1, 2);m_layout.addWidget(&m_check, 2, 0);m_layout.addWidget(&m_radiogroup, 2, 1);m_layout.addWidget(&m_replaceallbutton, 2, 2);m_layout.addWidget(&m_cancelbutton, 3, 2);

替換功能的實現：

要實現替換操作，首先需要查找文本框中是否存在的字符串。如果存在字符串，則將鼠標標記的字符串替換。

void ReplaceDialog::onReplace(){QString target = m_edit.text();QString to = m_replaceedit.text();if((m_textedit != NULL) && (target != NULL) && (to != NULL)){QString select = m_textedit->textCursor().selectedText();if(select == target){m_textedit->insertPlainText(to);}onFind();}}void ReplaceDialog::onRepalceAll(){QString target = m_edit.text();QString to = m_replaceedit.text();if((m_textedit != NULL) && (target != NULL) && (to != NULL)){QString text = m_textedit->toPlainText();text.replace(target, to, m_check.isChecked() ? Qt::CaseSensitive : Qt::CaseInsensitive);m_textedit->clear();m_textedit->insertPlainText(text);}}

10、工具欄、狀態欄的顯示隱藏

在構建菜單欄、工具欄中ToolBar、StatusBar的QAction對象時，設置QAction對象的屬性。

        action->setCheckable(true);        action->setChecked(true);        connect(action, SIGNAL(triggered()), this, SLOT(onViewToolBar()));

槽函數如下：

void MainWindow::onViewStatusBar(){QStatusBar *sb = statusBar();bool visible = sb->isVisible();sb->setVisible(!visible);findToolBarItem("Status Bar")->setChecked(!visible);findMenuBarItem("Status Bar")->setChecked(!visible);}void MainWindow::onViewToolBar(){const QObjectList& list = children();for(int i = 0; i < list.count(); i++){QToolBar *tb = dynamic_cast<QToolBar*>(list[i]);if(tb != NULL){bool visible = tb->isVisible();tb->setVisible(!visible);findMenuBarItem("Tool Bar")->setChecked(!visible);findToolBarItem("Tool Bar")->setChecked(!visible);break;}}}

11、關于對話框

關于對話框用于標識軟件的信息，如：Logo、版本號、開發者信息、版權、聯系方式、項目信息等。

經典的關于對話框界面設計：

AboutDialog::AboutDialog(QWidget* parent):QDialog(parent, Qt::WindowCloseButtonHint), m_logo(this), m_info(this), m_close(this){QPixmap pm(":/res/pic/dt.png");pm = pm.scaled(120,120, Qt::KeepAspectRatio);m_logo.setPixmap(pm);m_logo.move(20, 20);m_logo.resize(120, 120);QPalette p = m_info.palette();p.setColor(QPalette::Active, QPalette::Base, palette().color(QPalette::Active, QPalette::Background));p.setColor(QPalette::Inactive, QPalette::Base, palette().color(QPalette::Inactive, QPalette::Background));m_info.setPalette(p);m_info.move(200, 30);m_info.resize(180, 130);m_info.setFrameStyle(QPlainTextEdit::NoFrame);m_info.setReadOnly(true);m_info.insertPlainText("NotePad Project\\Platform: Qt 5.6.2\\Version: 1.0.0\\Author: Scorpio");m_close.setText("Close");m_close.move(273, 175);m_close.resize(100, 30);setWindowTitle("About NotePad");setFixedSize(395, 230);connect(&m_close, SIGNAL(clicked()), this, SLOT(onClose()));}

12、字體設置

設置文本框中的字體的屬性。

字體設置通過QFontDialog對話框實現

槽函數如下：

void MainWindow::onFormatFont(){bool ok = false;QFont font = QFontDialog::getFont(&ok, mainEditor.font(), this);if(ok){mainEditor.setFont(font);}}

13、換行

QPlainTextEdit支持換行操作。在菜單欄、工具欄創建QAction對象時設置屬性。

       action->setCheckable(true);        action->setChecked(true);        connect(action, SIGNAL(triggered()), this, SLOT(onFormatWrap()));槽函數如下：void MainWindow::onFormatWrap(){QPlainTextEdit::LineWrapMode mode = mainEditor.lineWrapMode();if(mode == QPlainTextEdit::NoWrap){mainEditor.setLineWrapMode(QPlainTextEdit::Widgetwidth="360px",height="auto" />

14、幫助文檔

QDesktopServices提供了一系列桌面開發的服務接口。

通過QDesktopServices的成員函數打開幫助文檔。

[static] bool QDesktopServices::openUrl(const QUrl &url)

打開網頁：

QDesktopServices::openUrl(QUrl("http://9291927.blog.51cto.com/"));

打開文檔：

QDesktopServices::openUrl(QUrl("file:///C:/Documents and Settings/All Users/Desktop/help.pdf"));

15、程序配置文件

程序狀態的保存可以通過在程序退出前保存程序狀態參數到文件（數據庫），程序啟動時從配置文件讀出狀態參數并恢復。

程序狀態參數的存儲方式：

A、文本文件格式（XML、Json等）

B、輕量級數據庫（Access、SQLite等）

C、二進制文件格式

通過二進制數據流將狀態參數直接存儲帶文件中。

Appconfig.h文件：

#ifndef APPCONFIG_H#define APPCONFIG_H#include <QObject>#include <QFont>#include <QFile>#include <QDataStream>#include <QApplication>class AppConfig : public QObject{Q_OBJECTpublic:explicit AppConfig(QObject *parent = 0);explicit AppConfig(QFont editorfont, bool isautowrap, bool istoolbarvisible, bool isstatusbarvisible, QObject *parent = 0);bool store();QFont editorFont();bool isAutoWrap();bool isToolBarVisible();bool isStatusBarVisible();bool isValid();private:bool restore();private:QFont m_editorFont;bool m_isAutoWrap;bool m_isToolBarVisible;bool m_isStatusBarVisible;bool m_isValid;};#endif // APPCONFIG_H

Appconfig.cpp文件：

#include "AppConfig.h"AppConfig::AppConfig(QObject *parent) : QObject(parent){m_isValid = restore();}AppConfig::AppConfig(QFont editorfont, bool isautowrap, bool istoolbarvisible, bool isstatusbarvisible, QObject *parent){m_editorFont = editorfont;m_isAutoWrap = isautowrap;m_isToolBarVisible = istoolbarvisible;m_isStatusBarVisible = isstatusbarvisible;m_isValid = true;}QFont AppConfig::editorFont(){return m_editorFont;}bool AppConfig::isAutoWrap(){return m_isAutoWrap;}bool AppConfig::isStatusBarVisible(){return m_isStatusBarVisible;}bool AppConfig::isToolBarVisible(){return m_isToolBarVisible;}bool AppConfig::isValid(){return m_isValid;}bool AppConfig::store(){bool ret = true;QFile file(QApplication::applicationDirPath() + "/config.dat");if(file.open(QIODevice::WriteOnly)){QDataStream out(&file);out.setVersion(QDataStream::Qt_5_6);out << m_editorFont;out << m_isAutoWrap;out << m_isToolBarVisible;out << m_isStatusBarVisible;file.close();}else{ret = false;}return ret;}bool AppConfig::restore(){bool ret = true;QFile file(QApplication::applicationDirPath() + "/config.dat");if(file.open(QIODevice::ReadOnly)){QDataStream in(&file);in.setVersion(QDataStream::Qt_5_6);in >> m_editorFont;in >> m_isAutoWrap;in >> m_isToolBarVisible;in >> m_isStatusBarVisible;file.close();}else{ret = false;}return ret;}

從配置文件的讀取狀態參數恢復程序狀態在構造函數中：

bool MainWindow::construct(){bool ret = true;AppConfig config;ret = ret && initMenuBar();ret = ret && initToolBar();ret = ret && initStatusBar();ret = ret && initMainEditor();if(config.isValid()){mainEditor.setFont(config.editorFont());if(!config.isAutoWrap()){mainEditor.setLineWrapMode(QPlainTextEdit::NoWrap);findToolBarItem("Auto Wrap")->setCheckable(false);findMenuBarItem("Auto Wrap")->setChecked(false);}if(!config.isToolBarVisible()){toolBar()->setVisible(false);findMenuBarItem("Tool Bar")->setChecked(false);findToolBarItem("Tool Bar")->setChecked(false);}if(!config.isStatusBarVisible()){statusBar()->setVisible(false);findMenuBarItem("Status Bar")->setChecked(false);findToolBarItem("Status Bar")->setChecked(false);}}return ret;}

狀態參數保存到配置文件在析構函數中：

MainWindow::~MainWindow(){QFont font = mainEditor.font();bool isautowrap = (mainEditor.lineWrapMode() == QPlainTextEdit::Widgetwidth="360px",height="auto" />

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