Qt5模型/视图结构-视图(View)

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实现自定义的View，可继承自QAbstractItemView类，对所需的纯虚函数进行重定义与实现，对于QAbstractItemView类中的纯虚函数，在子类中必须进行重定义，但不一定要实现，可根据需要选择实现。

DEMO

mainwindow.h

#ifndef MAINWINDOW_H #define MAINWINDOW_H#include <QMainWindow> #include <QStandardItem> #include <QTableView> #include <QMenuBar> #include <QMenu> #include <QAction> #include <QSplitter> #include "histogramview.h"class MainWindow : public QMainWindow { Q_OBJECTpublic: MainWindow(QWidget *parent = 0); ~MainWindow(); void creatAction(); void creatMenu(); void setupModel(); void setupView(); void openFile(QString); public slots: void slotOpen(); private: QMenu *fileMenu; QAction *openAct; QStandardItemModel *model; QTableView *table; QSplitter *splitter; HistogramView *histogram; };#endif // MAINWINDOW_H

histogramview.h

#ifndef HISTOGRAMVIEW_H #define HISTOGRAMVIEW_H#include <QAbstractItemView> #include <QItemSelectionModel> #include <QRegion> #include <QMouseEvent> #include <QList>//自定义HistogramView类继承自QAbstractItemView类，用于对表格数据进行柱状图显示 class HistogramView:public QAbstractItemView { Q_OBJECT public: HistogramView(QWidget *parent=0); //虚函数的声明 //QAbstractItemView类中的纯虚函数，这些纯虚函数不一定要实现，可以根据 //需要选择性的实现，但一定要声明 QRect visualRect(const QModelIndex &index) const; void scrollTo(const QModelIndex &index,ScrollHint hint=EnsureVisible); //当鼠标在视图中单击或位置发生改变时触发，它返回鼠标所在点的QModelIndex值，若鼠标 //处在某个数据项的区域中，则返回此数据的Index值，否则返回一个空的Index QModelIndex indexAt(const QPoint &point) const; //为selections赋初值 void setSelectionModel(QItemSelectionModel *selectionModel); QRegion itemRegion(QModelIndex index); void paintEvent(QPaintEvent *); //柱状统计图可以被鼠标单击选择，选中后以不同的方式显现 void mousePressEvent(QMouseEvent *event); protected slots: //当数据项发生改变时,此槽函数将响应 void selectionChanged(const QItemSelection &selected,const QItemSelection &deselected); //当模型中的数据发生变更时，此槽函数响应 void dataChanged(const QModelIndex &topLeft, const QModelIndex &bottomRight); protected: //虚函数声明 QModelIndex moveCursor(QAbstractItemView::CursorAction cursorAction, Qt::KeyboardModifiers modifiers); int horizontalOffset() const; int verticalOffset() const; bool isIndexHidden(const QModelIndex &index) const; //将位于QRect内的数据项按照SelectionFlags(描述被选择的数据项以何种方式进行更新) //指定的方式进行更新。 void setSelection(const QRect &rect,QItemSelectionModel::SelectionFlags flags); QRegion visualRegionForSelection(const QItemSelection &selection) const; private: QItemSelectionModel *selections; //用于保存与视图选择项相关的内容 QList<QRegion> MRegionList; //用于保存其中某一类型柱状图的区域范围，而每个区域是QList中的一个值 QList<QRegion> FRegionList; QList<QRegion> SRegionList; };#endif // HISTOGRAMVIEW_H

mainwindow.cpp

#include "mainwindow.h" #include <QFileDialog> #include <QFile> #include <QTextStream> #include <QStringList>MainWindow::MainWindow(QWidget *parent) : QMainWindow(parent) { creatAction(); creatMenu(); setupModel(); setupView(); setWindowTitle(tr("View Example")); resize(600,600); }MainWindow::~MainWindow() {}void MainWindow::creatAction() { openAct=new QAction(tr("打开"),this); connect(openAct,SIGNAL(triggered(bool)), this,SLOT(slotOpen())); }void MainWindow::creatMenu() { fileMenu=new QMenu(tr("文件"),this); fileMenu->addAction(openAct); menuBar()->addMenu(fileMenu); } //新建一个model,并设置表头数据 void MainWindow::setupModel() { model=new QStandardItemModel(4,4,this); model->setHeaderData(0,Qt::Horizontal,tr("部门")); 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() { /* table=new QTableView; //新建一个QTableView table->setModel(model); //为QTableView对象设置相同的Model QItemSelectionModel *selectionModel=new QItemSelectionModel(model); table->setSelectionModel(selectionModel); //连接选择模型的selectionModel()信号与QTabelView对象的selectionChanged()槽函数 //以便使自定义的HistogramView对象中的选择变化能够反映到QTabelView对象的显示中 connect(selectionModel,SIGNAL(selectionChanged(QItemSelection, QItemSelection)), table,SLOT(selectionChanged(QItemSelection, QItemSelection))); splitter=new QSplitter; splitter->setOrientation(Qt::Vertical); splitter->addWidget(table); setCentralWidget(splitter); */ splitter=new QSplitter; splitter->setOrientation(Qt::Vertical); histogram=new HistogramView(splitter); //新建一个Histogram对象 histogram->setModel(model); //为HistogramView对象设置相同的Model table=new QTableView; table->setModel(model); QItemSelectionModel *selectionModel=new QItemSelectionModel (model); table->setSelectionModel(selectionModel); histogram->setSelectionModel(selectionModel); //新建的QItemSelectionModel //对象作为QTableView对象和HistogramView //对象使用的选择模型 splitter->addWidget(table); splitter->addWidget(histogram); setCentralWidget(splitter); //连接槽函数，以便使QTableView对象中的选择变化能够反映到自定义的HistogramView对象的显示中 connect(selectionModel,SIGNAL(selectionChanged(QItemSelection,QItemSelection)), table,SLOT(selectionChanged(QItemSelection,QItemSelection))); connect(selectionModel,SIGNAL(selectionChanged(QItemSelection,QItemSelection)), histogram,SLOT(selectionChanged(QItemSelection,QItemSelection)));} //slotOpne()槽函数完成打开标准文件对话框 void MainWindow::slotOpen() { QString name; name=QFileDialog::getOpenFileName(this,"打开",".","histogram files(*.txt)"); if(!name.isEmpty()) { openFile(name); } } //openFile()函数完成打开所选的文件的内容 void MainWindow::openFile(QString path) { if(!path.isEmpty()) { QFile file(path); 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()) { model->insertRows(row,1,QModelIndex()); 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(); } } //end if(!path.isEmpty()) }

histogramview.cpp

#include "histogramview.h" #include <QPainter>HistogramView::HistogramView(QWidget *parent):QAbstractItemView(parent) {} //paintEvent()函数完成柱状统计图绘制的工作 void HistogramView::paintEvent(QPaintEvent *) { //以viewport()作为绘图设备新建一个QPainter对象 QPainter painter(viewport()); painter.setPen(Qt::black); int x0=40; int y0=250; /*完成了x,y坐标轴的绘制,并标注坐标轴的变量*/ //y坐标轴 painter.drawLine(x0,y0,40,30); painter.drawLine(38,32,40,30); painter.drawLine(40,30,42,32); painter.drawText(20,30,tr("人数")); for(int i=0;i<5;i++) { painter.drawLine(-1,-i*50,1,-i*50); painter.drawText(-20,-i*50,tr("%1").arg(i*5)); } //x轴 painter.drawLine(x0,y0,540,250); painter.drawLine(538,248,540,250); painter.drawLine(540,250,538,252); painter.drawText(545,250,tr("部门")); int posD=x0+20; int row; 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+20,dep); posD+=50; } /*完成了表格第1列数据的柱状统计图的绘制*/ //男 int posM=x0+20; MRegionList.clear(); for(row=0;row<model()->rowCount(rootIndex());row++) { QModelIndex index=model()->index(row,1,rootIndex()); int male=model()->data(index).toDouble(); int width=10; //使用不同画刷颜色区别选中与未被选中的数据项 if(selections->isSelected(index)) { //Qt::Dense3Pattern是QBrush style //如果被选中，则画刷的style改变 painter.setBrush(QBrush(QColor(91,75,0,255),Qt::Dense3Pattern)); } else { painter.setBrush(Qt::blue); } //根据当前数据项的值按照比例绘制一个方形表示此项数据 painter.drawRect(QRect(posM,y0-male*10,width,male*10)); QRegion regionM(posM,y0-male*10,width,male*10); //将此数据所占据的区域保存到MRegionList列表中，为后面的数据项做准备 MRegionList.insert(row,regionM); posM+=50; } //end for(row=0;row<model()->rowCount(rootIndex());row++) /*完成了表格第2列数据的柱状统计图绘制*/ //女 int posF=x0+30; FRegionList.clear(); 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); } painter.drawRect(QRect(posF,y0-female*10,width,female*10)); QRegion regionF(posF,y0-female*10,width,female*10); FRegionList.insert(row,regionF); posF+=50; } //end for(row=0;row<=model()->rowCount(rootIndex());row++) /*完成了表格第3列数据的柱状统计图的绘制*/ //退休 int posS=x0+40; SRegionList.clear(); 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); } painter.drawRect(QRect(posS,y0-retire*10,width,retire*10)); QRegion regionS(posS,y0-retire*10,width,retire*10); SRegionList.insert(row,regionS); posS+=50; } //end for(row=0;row<=model()->rowCount(rootIndex());row++) } //dataChanged函数实现当model中的数据更改时，调用绘图设备的update()函数 //进行更新，反映数据的变化 void HistogramView::dataChanged(const QModelIndex &topLeft, const QModelIndex &bottomRight) { QAbstractItemView::dataChanged(topLeft,bottomRight); viewport()->update(); } //setSelectionModel()函数为selections赋初值 void HistogramView::setSelectionModel(QItemSelectionModel *selectionModel) { selections=selectionModel; } //selectionChanged()函数中完成当数据项发生变化时调用update()函数 //重绘绘图设备即可工作 void HistogramView::selectionChanged(const QItemSelection &selected, const QItemSelection &deselected) { viewport()->update(); } //鼠标按下事件函数mousePressEvent(),在调用setSelection()函数时确定鼠标单击 //点是否在某个数据项的区域内，并设置选择项 void HistogramView::mousePressEvent(QMouseEvent *event) { QAbstractItemView::mousePressEvent(event); setSelection(QRect(event->pos().x(),event->pos().y(),1,1), QItemSelectionModel::SelectCurrent); } void HistogramView::setSelection(const QRect &rect, QItemSelectionModel::SelectionFlags flags) { int rows=model()->rowCount(rootIndex()); //获取总行数 int columns=model()->columnCount(rootIndex()); //获取总列数 //用于保存被选中的数据项的Index值,此处只实现了用鼠标单击选择，而没有实现 //鼠标拖曳框选，因此，鼠标动作只可能选中一个数据项。若实现框选，则可使用 //QModelIndexList来保存所有被选中的数据项的Index值 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); //返回指定index的数据项所占用的区域 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) //检查当前点是否处于第一列(男)数据的区域中 { 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; } } //合计列 foreach(region,FRegionList) { if(region.contains(newPoint)) { int row=FRegionList.indexOf(region); QModelIndex index=model()->index(row,2,rootIndex()); return index; } } return QModelIndex(); } 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{} 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)//退休 region = SRegionList[index.row()]; return region; }

main.cpp

#include "mainwindow.h" #include <QApplication>int main(int argc, char *argv[]) { QApplication a(argc, argv); MainWindow w; w.show(); return a.exec(); }

注意.pro文件如下

#------------------------------------------------- # # Project created by QtCreator 2018-09-05T19:29:45 # #-------------------------------------------------QT += core guigreaterThan(QT_MAJOR_VERSION, 4): QT += widgetsTARGET = CH803 TEMPLATE = appDEFINES += QT_DEPRECATED_WARNINGS #新增加的SOURCES += main.cpp\ mainwindow.cpp \ histogramview.cppHEADERS += mainwindow.h \ histogramview.h

在该目录下新建文件histogram.txt

E:\QT\CH803\build-CH803-Desktop_Qt_5_6_2_MinGW_32bit-Debug

内容如下

一部,12,3,5 二部,16,4,0 三部,18,4,2 四部,10,3,1 五部,11,4,3 六部,12,2,4 七部,14,3,5 八部,9,1,1

运行效果如下

备注

这个程序里有几个函数我还是没搞懂，不太清楚其中的逻辑