8.1 概述
MVC設(shè)計(jì)模式是起源于Smalltalk的一種與用戶界面相關(guān)的設(shè)計(jì)模式。通過使用此模型，可以有效地分離數(shù)據(jù)和用戶界面。MVC設(shè)計(jì)模式包括三個(gè)元素：表示數(shù)據(jù)的模型 （Model）、表示用戶界面的視圖（View）和定義了用戶在界面上的操作控制（Controller）。 與MVC設(shè)計(jì)模式類似，Qt引入了模型/視圖結(jié)構(gòu)用于完成數(shù)據(jù)與界面的分離，即InterView框架。但不同的是，Qt的InterView框架中把視圖和控制部件結(jié)合在一起，使得? 框架更為簡(jiǎn)潔。為了靈活地處理用戶輸入，InterView框架引入了代理（Delegate）。通過使用代理，能夠自定義數(shù)據(jù)條目（item）的顯示和編輯方式。 Qt的模型/視圖結(jié)構(gòu)分為了三種部分：模式（Model）、視圖（View）和代理（Delegate）。其中，模型與數(shù)據(jù)通信，并為了其它部件提供接口；而視圖從模型中獲得用來 引用數(shù)據(jù)條目的模型索引（Model Index）。在視圖中，代理負(fù)責(zé)繪制數(shù)據(jù)條目，當(dāng)編輯條目時(shí)，代理和模型直接進(jìn)行通信。模型/視圖/代理之間通過信號(hào)和槽進(jìn)行通信。 它們之間的關(guān)系如下： 數(shù)據(jù)發(fā)生改變時(shí)，模型發(fā)出信號(hào)通知視圖。 用戶對(duì)界面進(jìn)行操作，視圖發(fā)生信號(hào)。 代理發(fā)出信號(hào)告知模型和視圖編輯器目前的狀態(tài)。


基本概念 1、模型（Model） InterView框架中的所有模型都基于抽象基類QAbstractItemModel類，此類由QProxyModel、QAbstractListModel、QAbstractTableModel、QAbstractProxyModel、 QDirModel、QFileSystemModel、QHelpContentModel?和?QStandardItemModel類繼承。 2、視圖（View） InterView框架中的所有視圖都基于抽象基類QAbstractItemView類，此類由QColumnView、QHeaderView、QListView、QTableView和QTreeView類繼承。 3、代理（Delegate） InterView框架中的所有代理都基于抽象基類QAbstractItemDelegate類，此類由QItemDelegate?和?QStyledItemDelegate類繼承。
運(yùn)行效果


main.cpp
#include "mainwindow.h" #include <QAbstractItemModel> #include <QAbstractItemView> #include <QItemSelectionModel> #include <QApplication> #include <QDirModel> #include <QTreeView> #include <QListView> #include <QTableView> #include <QSplitter> /* * 新建一個(gè)QDirModel對(duì)象，對(duì)數(shù)據(jù)訪問做準(zhǔn)備，QDirModel的創(chuàng)建還可以設(shè)置過濾器，即只有符合條件的文件或目錄才能被訪問 * QDirModel類繼承自QAbstractItemModel類，為訪問本地文件系統(tǒng)提供數(shù)據(jù)模型，它提供了新建、刪除、創(chuàng)建目錄等一系列與 * 文件操作相關(guān)的函數(shù)，此處只是用來顯示本地文件系統(tǒng) * * 新建三種不同的View對(duì)象，以便文件目錄可以以三種不同的方式顯示 * * tree.setModel(&model)：調(diào)用setModel()函數(shù)設(shè)置View對(duì)象的Model為QDirModel對(duì)象的model。 * * tree.setSelectionMode (QAbstractItemView::MultiSelection)：設(shè)置QTreeView對(duì)象的選擇方式為多選 * *list.setSelectionModel (tree.selectionModel ())：設(shè)置QListView對(duì)象與QTreeView對(duì)象使用相同的選擇類型 * * 為了實(shí)現(xiàn)雙擊QTreeView對(duì)象中的某個(gè)目錄時(shí)，QListView對(duì)象和QTableView對(duì)象中顯示此選定目錄下的所有文件和目錄， * 需要鏈接QTreeView對(duì)象的doubleClicked()信號(hào)與QListView對(duì)象和QTableView對(duì)象的setRootIndex()槽函數(shù) */ int main(int argc, char *argv[]) { QApplication a(argc, argv); QDirModel model; QTreeView tree; QListView list; QTableView table; tree.setModel (&model); list.setModel (&model); table.setModel (&model); tree.setSelectionMode (QAbstractItemView::MultiSelection); list.setSelectionModel (tree.selectionModel ()); table.setSelectionModel (tree.selectionModel ()); QObject::connect (&tree, SIGNAL(doubleClicked(QModelIndex)), &list, SLOT(setRootIndex(QModelIndex))); QObject::connect (&tree, SIGNAL(doubleClicked(QModelIndex)), &table, SLOT(setRootIndex(QModelIndex))); QSplitter *spliter = new QSplitter; spliter->addWidget (&tree); spliter->addWidget (&list); spliter->addWidget (&table); spliter->setWindowTitle (QObject::tr ("Model/View")); spliter->show(); return a.exec(); }
8.2 模型（Model） 實(shí)現(xiàn)自定義模型可以通過QAbstractItemModel類繼承，也可以通過QAbstractListModel和QAbstractTableModel類繼承實(shí)現(xiàn)列表模型或表格模型。在數(shù)值代碼保存，然后 通過外鍵關(guān)聯(lián)操作來查找其真實(shí)的含義，這一方法為了避免冗余。
Item主要角色及其描述

常量	描述
Qt::DisplayRole	顯示文字
Qt::DecorationRole	繪制裝飾數(shù)據(jù)（通常是圖標(biāo)）
Qt::EditRole	在編輯器中編輯的數(shù)據(jù)
Qt::ToolTipRole	工具提示
Qt::StatusTipRole	狀態(tài)欄提示
Qt::WhatsThisRole	What's This文字
Qt::SizeHintRole	尺寸提示
Qt::FontRole	默認(rèn)代理的繪制使用的字體
Qt::TextAlignmentRole	默認(rèn)代理的對(duì)齊方式
Qt::BackgroundRole	默認(rèn)代理的背景畫刷
Qt::ForegroundRole	默認(rèn)代理的前景畫刷
Qt::CheckStateRole	默認(rèn)代理的檢查框狀態(tài)
Qt::UserRole	用戶自定義的數(shù)據(jù)的起始位置

運(yùn)行畫面


modelex.h
#ifndef MODELEX_H #define MODELEX_H #include <QAbstractTableModel> #include <QMap> #include <QVector> #include <QStringList> /* * QMap<Key,T>提供了一個(gè)從類型為Key的鍵到類型為T的值的映射。 * rowCount()、columnCount()、data()和返回表頭數(shù)據(jù)的headerData()函數(shù) * 是QAbstractTableModel類的純數(shù)函數(shù) * * 純虛函數(shù)是一種特殊的虛函數(shù)，在許多情況下，在基類中不能對(duì)虛函數(shù)給出有意義的實(shí)現(xiàn)， * 而把它聲明為純虛函數(shù)，它的實(shí)現(xiàn)留給該基類的派生類去做。這就是純虛函數(shù)的作用 */ class ModelEx : public QAbstractTableModel { public: explicit ModelEx(QObject *parent = 0); virtual int rowCount (const QModelIndex &parent) const; virtual int columnCount (const QModelIndex &parent) const; QVariant data(const QModelIndex &index, int role) const; QVariant headerData (int section, Qt::Orientation orientation, int role) const; signals: public slots: private: QVector<short> army; //定義一個(gè)短型軍種類型容器 QVector<short> weaponType; //定義一個(gè)短型武器類型容器 QMap<short, QString> armyMap; //定義一個(gè)從short類型的鍵值到類型QString的值得映射 QMap<short, QString> weaponTypeMap; //定義一個(gè)從short類型的鍵值到類型QString的值得映射 QStringList weapon; //定義一個(gè)字符串武器鏈表 QStringList header; //定義一個(gè)頭結(jié)點(diǎn)鏈表 void populateModel(); //完成表格數(shù)據(jù)的初始化填充 }; #endif // MODELEX_H
modelex.cpp
#include "modelex.h" ModelEx::ModelEx(QObject *parent) : QAbstractTableModel(parent) { armyMap[1] = tr("空軍"); armyMap[2] = tr("海軍"); armyMap[3] = tr("陸軍"); armyMap[4] = tr("海軍陸戰(zhàn)隊(duì)"); weaponTypeMap[1] = tr("轟炸機(jī)"); weaponTypeMap[2] = tr("航空母艦"); weaponTypeMap[3] = tr("直升機(jī)"); weaponTypeMap[4] = tr("兩棲攻擊艦"); weaponTypeMap[5] = tr("驅(qū)逐艦"); weaponTypeMap[6] = tr("兩棲戰(zhàn)艦"); weaponTypeMap[7] = tr("坦克"); weaponTypeMap[8] = tr("戰(zhàn)斗機(jī)"); populateModel (); } void ModelEx::populateModel () { header << tr("軍種") << tr("種類") << tr("武器"); army << 1 << 2 << 3 << 4 << 4 << 2 << 3 << 1; weaponType << 1 << 2 << 3 << 4 <<5 << 6 << 7 << 8; weapon << tr("B-2") << tr("尼米茲級(jí)") << tr("阿帕奇") << tr("黃蜂級(jí)") << tr("阿利伯克級(jí)") << tr("AAAV") << tr("MIAI") << ("F-22"); } /* * 返回行 */ int ModelEx::rowCount (const QModelIndex &parent) const { return army.size (); } /* * 返回列 */ int ModelEx::columnCount (const QModelIndex &parent) const { return 3; } /* * QVariant類類似于C++的聯(lián)合（union）數(shù)據(jù)類型，它不僅能夠保存很多Qt類型的值，包括QColor、QBrush、QFont、 * QPen、QRect、QString和QSize等，也能夠存放容器類的值。 * data()函數(shù)返回指定索引的數(shù)據(jù)，即將數(shù)值映射為文字 */ QVariant ModelEx::data (const QModelIndex &index, int role) const { if(!index.isValid ()) { return QVariant(); } /*Qt::DisplayRole用來存取視圖中顯示的文字*/ if(role == Qt::DisplayRole) { switch(index.column ()) { case 0: return armyMap[army[index.row ()]]; break; case 1: return weaponTypeMap[weaponType[index.row ()]]; break; case 2: return weapon[index.row ()]; break; default: return QVariant(); break; } } return QVariant(); } /* * headerData()函數(shù)返回固定的表頭數(shù)據(jù)，設(shè)置水平表頭的標(biāo)題 */ QVariant ModelEx::headerData (int section, Qt::Orientation orientation, int role) const { if(role == Qt::DisplayRole && orientation == Qt::Horizontal) return header[section]; return QAbstractTableModel::headerData (section, orientation, role); }
main.cpp
#include <QApplication> #include "modelex.h" #include <QTableView> int main(int argc, char *argv[]) { QApplication a(argc, argv); ModelEx modelEx; QTableView view; view.setModel(&modelEx); view.setWindowTitle(QObject::tr("modelEx")); view.resize(400,400); view.show(); return a.exec(); }
8.3 視圖（View） 實(shí)現(xiàn)自定義的View，可繼承自QAbstractItemView類，對(duì)所需的純虛函數(shù)進(jìn)行重定義與實(shí)現(xiàn)，對(duì)于QAbstractItemView類中的純虛函數(shù)，在子類中必須進(jìn)行重定義， 但不一定要實(shí)現(xiàn)，可根據(jù)需要選擇實(shí)現(xiàn)。
顯示結(jié)果


mainwindow.h
#ifndef MAINWINDOW_H #define MAINWINDOW_H #include <QMainWindow> #include <QStandardItemModel> #include <QTableView> #include <QMenuBar> #include <QMenu> #include <QAction> #include <QSplitter> #include "histogramview.h" class MainWindow : public QMainWindow { Q_OBJECT public: MainWindow(QWidget *parent = 0); ~MainWindow(); void createAction(); void createMenu(); void setupModel(); void setupView(); void openFile(QString); private: QMenu *fileMenu; QAction *openAct; QStandardItemModel *model; QTableView *table; QSplitter *splitter; HistogramView *histogram; public slots: void slotOpen(); }; #endif // MAINWINDOW_H
mainwindow.cpp
#include "mainwindow.h" #include <QFileDialog> #include <QFile> #include <QTextStream> #include <QStringList> MainWindow::MainWindow(QWidget *parent) : QMainWindow(parent) { createAction (); createMenu (); setupModel (); setupView (); setWindowTitle (tr("View Example")); resize(600, 660); } MainWindow::~MainWindow() { } void MainWindow::createAction () { openAct = new QAction(tr("打開"), this); connect (openAct, SIGNAL(triggered(bool)), this, SLOT(slotOpen())); } /* * 創(chuàng)建一個(gè)文件菜單欄 * 將openAct動(dòng)作插入到這個(gè)菜單欄里 */ void MainWindow::createMenu () { fileMenu = new QMenu(tr("文件"), this); fileMenu->addAction(openAct); menuBar ()->addMenu (fileMenu); } void MainWindow::setupModel () { model = new QStandardItemModel(4, 4, this); model->setHeaderData (0, Qt::Horizontal, tr("部門")); model->setHeaderData (1, Qt::Horizontal, tr("男")); model->setHeaderData (2, Qt::Horizontal, tr("女")); model->setHeaderData (3, Qt::Horizontal, tr("退休")); } void MainWindow::setupView () { splitter = new QSplitter; splitter->setOrientation (Qt::Vertical); histogram = new HistogramView(splitter); histogram->setModel (model); table = new QTableView; //新建一個(gè)QTableView對(duì)象 table->setModel (model); //為QTableView對(duì)象設(shè)置相同的Model /*新建一個(gè)QItemSelectModel對(duì)象作為QTableView對(duì)象使用的選擇模型*/ QItemSelectionModel *selectionModel = new QItemSelectionModel(model); table->setSelectionModel (selectionModel); histogram->setSelectionModel (selectionModel); splitter->addWidget (table); splitter->addWidget (histogram); setCentralWidget (splitter); connect (selectionModel, SIGNAL(selectionChanged(QItemSelection,QItemSelection)), table, SLOT(selectionChanged(QItemSelection,QItemSelection))); connect (selectionModel, SIGNAL(selectionChanged(QItemSelection,QItemSelection)), histogram, SLOT(selectionChanged(QItemSelection,QItemSelection))); } /* * 打開一個(gè)*.txt文件 * 如果文件非空讀取文件信息 */ void MainWindow::slotOpen () { QString name; name = QFileDialog::getOpenFileName (this, "打開", ".", "histogram files(*.txt)"); if(!name.isEmpty ()) { openFile (name); } } /* * 一行行讀取*.txt文件內(nèi)容，當(dāng)遇到“,”分割數(shù)據(jù) * QFile類提供了一個(gè)接口，用于讀取或?qū)懭胛募?/span> * QTextStream類可以方便地讀取單詞、行和數(shù)字。 * 在循環(huán)中一次讀取文件中的一行數(shù)據(jù)，然后插入到表格對(duì)應(yīng)的一行數(shù)據(jù)中 */ void MainWindow::openFile (QString path) { if(!path.isEmpty ()) { QFile file(path); if(file.open (QFile::ReadOnly | QFile::Text)) { QTextStream stream(&file); QString line; /*從文本中移除一行的數(shù)據(jù)*/ model->removeRows (0, model->rowCount (QModelIndex()), QModelIndex()); int row = 0; do { line = stream.readLine (); if(!line.isEmpty ()) { /*設(shè)置一行插入多個(gè)數(shù)據(jù)，一次插入一個(gè)數(shù)據(jù)*/ model->insertRows (row, 1, QModelIndex()); QStringList pieces = line.split (",", QString::SkipEmptyParts); /*將數(shù)據(jù)設(shè)置到row行、0、1、2、3列*/ model->setData (model->index (row, 0, QModelIndex()), pieces.value (0)); model->setData (model->index (row, 1, QModelIndex()), pieces.value (1)); model->setData (model->index (row, 2, QModelIndex()), pieces.value (2)); model->setData (model->index (row, 3, QModelIndex()), pieces.value (3)); row++; } }while(!line.isEmpty ()); file.close (); } } }
histogramview.h
#ifndef HISTOGRAMVIEW_H #define HISTOGRAMVIEW_H #include <QAbstractItemView> #include <QItemSelection> #include <QRegion> #include <QMouseEvent> /* * visualRect (),scrollTo (),indexAt (),moveCursor (),horizontalOffset (),verticalOffset () * isIndexHidden (),setSelection ()和visualRegionForSelection ()：QAbstractItemView類中的純虛函數(shù) * 這些純虛函數(shù)不一定要實(shí)現(xiàn)，可以根據(jù)需要選擇性地實(shí)現(xiàn)，但一定要聲明。 * * QModelIndex indexAt(const QPoint &point) const：當(dāng)鼠標(biāo)在視圖中單擊或位置發(fā)生改變時(shí)被觸動(dòng)，它返回鼠標(biāo)所 * 在點(diǎn)的QModelIndex值。當(dāng)鼠標(biāo)處在某一個(gè)數(shù)據(jù)項(xiàng)的區(qū)域中，則返回此數(shù)據(jù)項(xiàng)的Index值，否則返回一個(gè)空的Index。 * * void mousePressEvent (QMouseEvent *event)：柱狀統(tǒng)計(jì)圖可以被鼠標(biāo)單擊選擇，選中后以不同的方式顯示。 * * selectionChanged (const QItemSelection &selected, const QItemSelection &deselected)：當(dāng)數(shù)據(jù)項(xiàng) * 選擇發(fā)生變化時(shí)，此槽函數(shù)將響應(yīng)。 * * void dataChanged (const QModelIndex &topLeft, const QModelIndex &bottomRight)：當(dāng)模型中的數(shù)據(jù)發(fā)生 * 變更時(shí)，此槽函數(shù)將響應(yīng)。 * * void setSelection (const QRect &rect, QItemSelectionModel::SelectionFlags flags)：將位于QRect內(nèi) * 的數(shù)據(jù)項(xiàng)按照SelectionFlags（描述被選擇的數(shù)據(jù)項(xiàng)以何種方式進(jìn)行更新）指定的方式進(jìn)行更新。QItemSelectModel類提供 * 多種可用的SelecttionFlags,常用的有QItemSelectModel::Select、QItemSelectModel::Current類。 * * QItemSelectionModel *selections：用于保存與視圖選擇項(xiàng)相關(guān)的內(nèi)容。 * * QList <QRegion> MRegionList：用于保存其中某一類型柱狀圖的區(qū)域范圍，而每個(gè)區(qū)域是QList中的一個(gè)值。 */ class HistogramView : public QAbstractItemView { public: HistogramView(QWidget *parent = 0); QRect visualRect (const QModelIndex &index) const; void scrollTo (const QModelIndex &index, ScrollHint hint=EnsureVisible); QModelIndex indexAt(const QPoint &point) const; //為selecttions賦初值 void setSelectionModel (QItemSelectionModel *selectionModel); QRegion itemRegion(QModelIndex index); void paintEvent (QPaintEvent *); void mousePressEvent (QMouseEvent *event); protected slots: void selectionChanged (const QItemSelection &selected, const QItemSelection &deselected); void dataChanged (const QModelIndex &topLeft, const QModelIndex &bottomRight); protected: QModelIndex moveCursor(QAbstractItemView::CursorAction cursorAction,Qt::KeyboardModifiers modifiers); int horizontalOffset () const; int verticalOffset () const; bool isIndexHidden (const QModelIndex &index) const; void setSelection (const QRect &rect, QItemSelectionModel::SelectionFlags flags); QRegion visualRegionForSelection (const QItemSelection &selection) const; private: QItemSelectionModel *selections; QList <QRegion> MRegionList; QList <QRegion> FRegionList; QList <QRegion> SRegionList; }; #endif // HISTOGRAMVIEW_H

histogramview.cpp
#include "histogramview.h" #include <QPainter> HistogramView::HistogramView(QWidget *parent) :QAbstractItemView(parent) { } //paintEvent()函數(shù)具體完成柱狀統(tǒng)計(jì)圖繪制的工作 void HistogramView::paintEvent (QPaintEvent *) { QPainter painter(viewport ()); //將viewport()作為繪圖設(shè)備新建一個(gè)QPainter對(duì)象 painter.setPen (Qt::black); int x0 = 40; int y0 = 280; //繪制y軸坐標(biāo) painter.drawLine (x0, y0, 40, 18); painter.drawLine (36, 22, 40, 18); painter.drawLine (44, 22, 40, 18); painter.drawText (27, 15, tr("人數(shù)")); for(int i = 0; i <= 5; i++) { painter.drawLine (40, 280 - (5 - i) * 50, 42, 280 - (5 - i) * 50); painter.drawText (25, 285 - (5 - i) * 50, tr("%1").arg ((5 - i) * 5)); } //繪制x軸坐標(biāo) painter.drawLine (x0, y0, 562, 280); painter.drawLine (558, 276, 562, 280); painter.drawLine (558, 284, 562, 280); painter.drawText (567, 285, tr("部門")); // for(int i = 0; i <= 9; i++) // { // painter.drawLine (490 - (8 - i) * 50, 280, 490 - (8 - i) * 50, 278); // painter.drawText (487 - (8 - i) * 50, 295, tr("%1").arg (i + 1)); // } int posD = x0 + 20; int row; //讀取文件中每一行的第一例數(shù)據(jù) for(row = 0; row < model()->rowCount (rootIndex ()); ++row) { QModelIndex index = model()->index (row, 0, rootIndex ()); QString dep = model ()->data (index).toString (); painter.drawText (posD, y0 + 15, dep); posD += 50; } /*完成了表格第1列數(shù)據(jù)的柱狀統(tǒng)計(jì)圖的繪制*/ //男 int posM = x0 + 20; for(row = 0; row < model()->rowCount (rootIndex ()); row++) { QModelIndex index=model()->index(row,1,rootIndex()); int male=model()->data(index).toDouble(); int width = 10; //使用不同畫刷顏色區(qū)別選中與未選中的數(shù)據(jù)項(xiàng) if(selections->isSelected(index)) painter.setBrush(QBrush(Qt::blue,Qt::Dense3Pattern)); else painter.setBrush(Qt::blue); //繪制長(zhǎng)方形條x，y，w，h painter.drawRect(QRect(posM, y0 - male * 10, width, male * 10)); QRegion regionM(posM, y0 - male * 10, width, male * 10); //將此數(shù)據(jù)所占據(jù)的區(qū)域保存到MRegionList列表中，為后面的數(shù)據(jù)項(xiàng)選擇做準(zhǔn)備。 MRegionList << regionM; posM += 50; } /*完成了表格第2列數(shù)據(jù)的柱狀統(tǒng)計(jì)圖的繪制*/ //女條目框 int posF = x0 + 30; for(row = 0; row < model()->rowCount (rootIndex ()); ++row) { QModelIndex index = model()->index (row, 2, rootIndex ()); int female = model()->data (index).toDouble (); int width = 10; if(selections->isSelected (index)) painter.setBrush (QBrush(Qt::red, Qt::Dense3Pattern)); else painter.setBrush (Qt::red); //繪制長(zhǎng)方形x，y，w，h painter.drawRect (QRect(posF, y0 - female * 10, width, female * 10)); QRegion regionF(posF, y0 - female * 10, width, female * 10); //將此數(shù)據(jù)所占據(jù)的區(qū)域保存到FRegionList列表中，為后面的數(shù)據(jù)項(xiàng)選擇做準(zhǔn)備。 FRegionList << regionF; posF += 50; } /*完成了表格第3列數(shù)據(jù)的柱狀統(tǒng)計(jì)圖的繪制*/ //退休條目框 int posS = x0 + 40; for(row = 0; row < model()->rowCount (rootIndex ()); ++row) { QModelIndex index = model ()->index (row, 3, rootIndex ()); int retire = model()->data (index).toDouble (); int width = 10; if(selections->isSelected (index)) painter.setBrush (QBrush(Qt::green, Qt::Dense3Pattern)); else painter.setBrush (Qt::green); //繪制長(zhǎng)方形x，y，w，h painter.drawRect (QRect(posS, y0 - retire * 10, width, retire * 10)); QRegion regionS(posS, y0 - retire * 10, width, retire * 10); SRegionList << regionS; posS += 50; } } /* * dataChanged()函數(shù)實(shí)現(xiàn)當(dāng)Model中的數(shù)據(jù)改變時(shí)，調(diào)用繪圖設(shè)備的update()函數(shù)進(jìn)行更新，反應(yīng)數(shù)據(jù)的變化 */ void HistogramView::dataChanged (const QModelIndex &topLeft, const QModelIndex &bottomRight) { QAbstractItemView::dataChanged (topLeft, bottomRight); viewport ()->update (); } /* * 設(shè)置選擇模式，至此View已經(jīng)能正確顯示表格的統(tǒng)計(jì)數(shù)據(jù)，而且對(duì)表格中的某個(gè)數(shù)據(jù)項(xiàng)進(jìn)行修改時(shí)能夠及時(shí)顯示將變化反應(yīng)在柱狀統(tǒng)計(jì)圖中 */ void HistogramView::setSelectionModel (QItemSelectionModel *selectionModel) { selections = selectionModel; } /* * 完成當(dāng)數(shù)據(jù)項(xiàng)發(fā)生變化時(shí)調(diào)用update()函數(shù)，重繪繪圖設(shè)備即可工作。此函數(shù)是將其他View中的操作引起的數(shù)據(jù)項(xiàng)選擇變化放映到自身 * View的顯示中。 */ void HistogramView::selectionChanged (const QItemSelection &selected, const QItemSelection &deselected) { viewport ()->update (); } /* * 在調(diào)用setSelection()函數(shù)確定鼠標(biāo)單擊點(diǎn)是否在某個(gè)數(shù)據(jù)項(xiàng)的區(qū)域內(nèi)，并設(shè)置選擇項(xiàng) */ void HistogramView::mousePressEvent (QMouseEvent *event) { QAbstractItemView::mousePressEvent (event); setSelection (QRect(event->pos().x (), event->pos().y (), 1, 1), QItemSelectionModel::SelectCurrent); } /* * QModelIndex selectIndex:用于保存被選中的數(shù)據(jù)項(xiàng)的Index值。此處只實(shí)現(xiàn)用鼠標(biāo)單擊選擇，而沒有實(shí)現(xiàn)鼠標(biāo)拖曳框選，因此，鼠標(biāo) * 動(dòng)作只可能選中一個(gè)數(shù)據(jù)項(xiàng)。 * * for循環(huán)里面:確定在rect中是否含有數(shù)據(jù)項(xiàng)。此處采用遍歷的方式將每個(gè)數(shù)據(jù)項(xiàng)的區(qū)域與rect區(qū)域進(jìn)行intersected操作，獲得兩者之間的 * 交集。若此交集不為空則說明此數(shù)據(jù)項(xiàng)被選中，將它的Index值賦給selectIndex。 * * QRegion region = itemRegion (index):返回指定index的數(shù)據(jù)項(xiàng)所占用的區(qū)域 * * 完成select()函數(shù)的調(diào)用，即完成最后對(duì)選擇項(xiàng)的設(shè)置工作。select()函數(shù)時(shí)在實(shí)現(xiàn)setSelection()函數(shù)的調(diào)用，即完成最后對(duì)選擇項(xiàng)的 * 設(shè)置。select()函數(shù)是在實(shí)現(xiàn)setSelection()函數(shù)時(shí)必須調(diào)用的。 */ void HistogramView::setSelection (const QRect &rect, QItemSelectionModel::SelectionFlags flags) { int rows = model()->rowCount (rootIndex ()); //獲得總行數(shù) int columns = model()->columnCount (rootIndex()); //獲得總列數(shù) QModelIndex selectedIndex; for(int row = 0; row < rows; ++row) { for(int column = 1; column < columns; ++column) { QModelIndex index = model()->index (row, column, rootIndex ()); QRegion region = itemRegion (index); if(!region.intersected (rect).isEmpty ()) selectedIndex = index; } } if(selectedIndex.isValid ()) selections->select (selectedIndex, flags); else { QModelIndex noIndex; selections->select (noIndex, flags); } } QModelIndex HistogramView::indexAt (const QPoint &point) const { QPoint newPoint(point.x (), point.y ()); QRegion region; //男列 foreach(region, MRegionList) { if(region.contains (newPoint)) { int row = MRegionList.indexOf (region); QModelIndex index = model()->index (row, 1, rootIndex ()); return index; } } //女列 foreach (region, FRegionList) { if(region.contains (newPoint)) { int row = FRegionList.indexOf (region); QModelIndex index = model ()->index (row, 2, rootIndex ()); return index; } } //合計(jì)列 foreach(region, SRegionList) { if(region.contains (newPoint)) { int row = SRegionList.indexOf (region); QModelIndex index = model()->index (row, 3, rootIndex ()); return index; } } return QModelIndex(); } QRegion HistogramView::itemRegion (QModelIndex index) { QRegion region; if(index.column () == 1) //男 region = MRegionList[index.row ()]; if(index.column () == 2) //女 region = FRegionList[index.row ()]; if(index.column () == 3) region = SRegionList[index.row ()]; return region; } QRect HistogramView::visualRect(const QModelIndex &index)const{} void HistogramView::scrollTo(const QModelIndex &index,ScrollHint){} QModelIndex HistogramView::moveCursor(QAbstractItemView::CursorAction cursorAction, Qt::KeyboardModifiers modifiers){} int HistogramView::horizontalOffset()const{} int HistogramView::verticalOffset()const{} bool HistogramView::isIndexHidden(const QModelIndex &index)const{} QRegion HistogramView::visualRegionForSelection(const QItemSelection &selection)const{}
8.4代理(Dlegate) 在表格中嵌入各種不同控件，通過表格中的控件對(duì)編輯的內(nèi)容進(jìn)行限定。通常情況下，這種在表格中插入空間的方式，空間始終顯示。在表格中控件數(shù)目較多時(shí)，將 影響表格的美觀。此時(shí)，可利用Delegate的方式實(shí)現(xiàn)同樣的效果，控件只有在需要編輯數(shù)據(jù)項(xiàng)時(shí)才會(huì)顯示，從而解決了上述所遇到的問題。 運(yùn)行效果如下：

main.cpp
#include "mainwindow.h" #include <QApplication> #include <QStandardItemModel> #include <QFile> #include <QTextStream> #include <QTableView> #include "datedelegate.h" #include "combodelegate.h" #include "spindelegate.h" int main(int argc, char *argv[]) { QApplication a(argc, argv); /*定義一個(gè)4*4的表格對(duì)象*/ QStandardItemModel model(4, 4); QTableView tableView; tableView.setModel (&model); DateDelegate dateDelegate; tableView.setItemDelegateForColumn (1, &dateDelegate); ComboDelegate comboDelegate; tableView.setItemDelegateForColumn (2, &comboDelegate); SpinDelegate spinDelegate; tableView.setItemDelegateForColumn (3, &spinDelegate); model.setHeaderData (0, Qt::Horizontal, QObject::tr("姓名")); model.setHeaderData (1, Qt::Horizontal, QObject::tr ("生日")); model.setHeaderData (2, Qt::Horizontal, QObject::tr("職業(yè)")); model.setHeaderData (3, Qt::Horizontal, QObject::tr("收入")); QFile file("test.txt"); if(file.open (QFile::ReadOnly | QFile::Text)) { QTextStream stream(&file); QString line; model.removeRows (0, model.rowCount (QModelIndex()), QModelIndex()); int row = 0; do{ line = stream.readLine (); if(!line.isEmpty ()) { /*一次插入一行數(shù)據(jù)，每次插入一個(gè)數(shù)據(jù)*/ model.insertRows (row, 1, QModelIndex()); /*當(dāng)遇到”,“跳過該項(xiàng)，將數(shù)據(jù)插入pieces鏈表中*/ QStringList pieces = line.split (",", QString::SkipEmptyParts); model.setData (model.index (row, 0, QModelIndex()), pieces.value(0)); model.setData (model.index (row, 1, QModelIndex()), pieces.value (1)); model.setData (model.index (row, 2, QModelIndex()), pieces.value (2)); model.setData (model.index (row, 3, QModelIndex()), pieces.value (3)); row++; } }while(!line.isEmpty ()); file.close (); } tableView.setWindowTitle (QObject::tr ("Delegate")); tableView.resize (450, 250); tableView.show(); return a.exec(); }
combodelegate.h
#ifndef COMBODELEGATE_H #define COMBODELEGATE_H #include <QItemDelegate> #include <QWidget> class ComboDelegate : public QItemDelegate { public: ComboDelegate(QObject *parent = 0); QWidget *createEditor (QWidget *parent, const QStyleOptionViewItem &option, const QModelIndex &index) const; void setEditorData (QWidget *editor, const QModelIndex &index) const; void setModelData (QWidget *editor, QAbstractItemModel *model, const QModelIndex &index) const; void updateEditorGeometry (QWidget *editor, const QStyleOptionViewItem &option, const QModelIndex &index) const; }; #endif // COMBODELEGATE_H

combodelegate.cpp
#include "combodelegate.h" #include <QComboBox> ComboDelegate::ComboDelegate(QObject *parent) : QItemDelegate(parent) { } /* * createEditor()函數(shù)中創(chuàng)建了一個(gè)QComboBox控件，并插入可現(xiàn)實(shí)的條目，安裝事件過濾器。 */ QWidget *ComboDelegate::createEditor (QWidget *parent, const QStyleOptionViewItem &option, const QModelIndex &index) const { QComboBox *editor = new QComboBox(parent); editor->addItem (tr("工人")); editor->addItem (tr("農(nóng)民")); editor->addItem (tr("醫(yī)生")); editor->addItem (tr("律師")); editor->addItem (tr("軍人")); editor->installEventFilter (const_cast<ComboDelegate*>(this)); return editor; } /* * 更新代理控件中的數(shù)據(jù)顯示 */ void ComboDelegate::setEditorData (QWidget *editor, const QModelIndex &index) const { QString str = index.model ()->data (index).toString (); QComboBox *box = static_cast<QComboBox*>(editor); int i = box->findText (str); box->setCurrentIndex (i); } /* * 更新model中的數(shù)據(jù) */ void ComboDelegate::setModelData (QWidget *editor, QAbstractItemModel *model, const QModelIndex &index) const { QComboBox *box = static_cast<QComboBox*>(editor); QString str = box->currentText (); model->setData (index, str); } void ComboDelegate::updateEditorGeometry (QWidget *editor, const QStyleOptionViewItem &option, const QModelIndex &index) const { editor->setGeometry (option.rect); }
datedelegate.h
#ifndef DATEDELEGATE_H #define DATEDELEGATE_H #include <QItemDelegate> #include <QWidget> class DateDelegate : public QItemDelegate { public: DateDelegate(QObject *parent = 0); QWidget *createEditor (QWidget *parent, const QStyleOptionViewItem &option, const QModelIndex &index) const; void setEditorData (QWidget *editor, const QModelIndex &index) const; void setModelData (QWidget *editor, QAbstractItemModel *model, const QModelIndex &index) const; void updateEditorGeometry (QWidget *editor, const QStyleOptionViewItem &option, const QModelIndex &index) const; }; #endif // DATEDELEGATE_H

datedelegate.cpp
#include "datedelegate.h" #include <QDateTimeEdit> DateDelegate::DateDelegate(QObject *parent) : QItemDelegate(parent) { } /* * 完成創(chuàng)建控件的工作，創(chuàng)建由參數(shù)中的QModelIndex對(duì)象指定的表項(xiàng)數(shù)據(jù)的編輯控件，并對(duì)控件的內(nèi)容進(jìn)行設(shè)定 * * 新建一個(gè)QDateTimeEdit對(duì)象作為編輯時(shí)的輸入控件 * 設(shè)置此QDateTimeEdit對(duì)象的顯示格式為yyyy-MM-dd，此為ISO標(biāo)準(zhǔn)顯示方式 * 設(shè)置日歷選擇的顯示以Popup的方式，即下拉菜單的方式顯示 * 調(diào)用QObject類的installEventFilter()函數(shù)安裝事件過濾器，使DateDelegate能夠捕獲QDateTimeEdit對(duì)象的事件 */ QWidget *DateDelegate::createEditor (QWidget *parent, const QStyleOptionViewItem &option, const QModelIndex &index) const { QDateTimeEdit *editor = new QDateTimeEdit(parent); editor->setDisplayFormat ("yyyy-MM-dd"); editor->setCalendarPopup (true); editor->installEventFilter (const_cast<DateDelegate*>(this)); return editor; } /* * QString dataStr = index.model ()->data (index).toString (): 獲取指定index數(shù)據(jù)項(xiàng)的數(shù)據(jù)，調(diào)用QModelIndex的 * model()函數(shù)可獲得提供index的Model對(duì)象，data()函數(shù)返回的是一個(gè)QVariant對(duì)象，toString()函數(shù)將它轉(zhuǎn)換為一個(gè)QString類型數(shù)據(jù) * * 通過QDate的fromString()函數(shù)將以QString類型表示的日期數(shù)據(jù)轉(zhuǎn)換為QDate類型。Qt::ISODate表示QDate類型的日期是以ISO格式 * 保存的，這樣最終轉(zhuǎn)換得的QDate數(shù)據(jù)也是ISO格式，使控件顯示與表格顯示保持一致。 * * QDateTimeEdit *edit = static_cast<QDateTimeEdit*>(editor):將editor裝換為QDateTimeEdit對(duì)象，以獲得編輯控件的 * 對(duì)象指針。 */ void DateDelegate::setEditorData (QWidget *editor, const QModelIndex &index) const { QString dataStr = index.model ()->data (index).toString (); QDate date = QDate::fromString (dataStr, Qt::ISODate); QDateTimeEdit *edit = static_cast<QDateTimeEdit*>(editor); edit->setDate (date); } /* * static_cast<QDateTimeEdit*>(editor):通過緊縮轉(zhuǎn)換獲得編輯控件的對(duì)象指針 * QDate date = edit->date ():獲得編輯控件中的數(shù)據(jù)更新 * model->setData (index, QVariant(date.toString (Qt::ISODate))): 調(diào)用setData()函數(shù) * 將數(shù)據(jù)修改更新到Model中。 * */ void DateDelegate::setModelData (QWidget *editor, QAbstractItemModel *model, const QModelIndex &index) const { QDateTimeEdit *edit = static_cast<QDateTimeEdit*>(editor); QDate date = edit->date (); model->setData (index, QVariant(date.toString (Qt::ISODate))); } void DateDelegate::updateEditorGeometry (QWidget *editor, const QStyleOptionViewItem &option, const QModelIndex &index) const { editor->setGeometry (option.rect); }
spindelegate.h
#ifndef SPINDELEGATE_H #define SPINDELEGATE_H #include <QItemDelegate> class SpinDelegate : public QItemDelegate { public: SpinDelegate(QObject *parent = 0); QWidget *createEditor (QWidget *parent, const QStyleOptionViewItem &option, const QModelIndex &index) const; void setEditorData (QWidget *editor, const QModelIndex &index) const; void setModelData (QWidget *editor, QAbstractItemModel *model, const QModelIndex &index) const; void updateEditorGeometry (QWidget *editor, const QStyleOptionViewItem &option, const QModelIndex &index) const; }; #endif // SPINDELEGATE_H

spindelegate.cpp
#include "spindelegate.h" #include <QSpinBox> SpinDelegate::SpinDelegate(QObject *parent) : QItemDelegate(parent) { } QWidget *SpinDelegate::createEditor (QWidget *parent, const QStyleOptionViewItem &option, const QModelIndex &index) const { QSpinBox *editor = new QSpinBox(parent); editor->setRange (0, 10000); editor->installEventFilter (const_cast<SpinDelegate*>(this)); return editor; } void SpinDelegate::setEditorData (QWidget *editor, const QModelIndex &index) const { int value = index.model ()->data (index).toInt (); QSpinBox *box = static_cast<QSpinBox*>(editor); box->setValue (value); } void SpinDelegate::setModelData (QWidget *editor, QAbstractItemModel *model, const QModelIndex &index) const { QSpinBox *box = static_cast<QSpinBox*>(editor); int value = box->value (); model->setData (index, value); } void SpinDelegate::updateEditorGeometry (QWidget *editor, const QStyleOptionViewItem &option, const QModelIndex &index) const { editor->setGeometry (option.rect); }

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